Protocol


ZegoApiCalledEventHandler	ZegoAudioDataHandler
ZegoAudioEffectPlayerEventHandler	ZegoAudioMixingHandler
ZegoCustomAudioProcessHandler	ZegoCustomVideoCaptureHandler
ZegoCustomVideoProcessHandler	ZegoCustomVideoRenderHandler
ZegoDataRecordEventHandler	ZegoEventHandler
ZegoMediaPlayerAudioHandler	ZegoMediaPlayerEventHandler
ZegoMediaPlayerVideoHandler	ZegoRangeAudioEventHandler

ZegoApiCalledEventHandler

Declared in ZegoExpressEventHandler.h

Methods

onApiCalledResult:funcName:info:

- (void)onApiCalledResult:(int) errorCode funcName:(NSString *) funcName info:(NSString *) info;

Method execution result callback

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
funcName	NSString *	Function name.
info	NSString *	Detailed error information.

Details

When the monitoring is turned on through [setApiCalledCallback], the results of the execution of all methods will be called back through this callback.

Trigger: When the developer calls the SDK method, the execution result of the method is called back.
Caution: It is recommended to monitor and process this callback in the development and testing phases, and turn off the monitoring of this callback after going online.

Available since: 2.3.0
Restrictions: None.

ZegoAudioDataHandler

Declared in ZegoExpressEventHandler.h

Methods

onCapturedAudioData:dataLength:param:

- (void)onCapturedAudioData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param;

The callback for obtaining the audio data captured by the local microphone.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.

Details

In non-custom audio capture mode, the SDK capture the microphone's sound, but the developer may also need to get a copy of the audio data captured by the SDK is available through this callback. When to trigger: On the premise of calling [setAudioDataHandler] to set the listener callback, after calling [startAudioDataObserver] to set the mask 0b01 that means 1 << 0, this callback will be triggered only when it is in the publishing stream state.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: None.

onPlaybackAudioData:dataLength:param:

- (void)onPlaybackAudioData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param;

The callback for obtaining the audio data of all the streams playback by SDK.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.

Details

This function will callback all the mixed audio data to be playback. This callback can be used for that you needs to fetch all the mixed audio data to be playback to proccess. When to trigger: On the premise of calling [setAudioDataHandler] to set the listener callback, after calling [startAudioDataObserver] to set the mask 0b10 that means 1 << 1, this callback will be triggered only when it is in the SDK inner audio and video engine started(called the [startPreview] or [startPlayingStream] or [startPublishingStream]).

Caution: This callback is a high-frequency callback. Please do not perform time-consuming operations in this callback. When the engine is not in the stream publishing state and the media player is not used to play media files, the audio data in the callback is muted audio data.

Restrictions: When playing copyrighted music, this callback will be disabled by default. If necessary, please contact ZEGO technical support.

onMixedAudioData:dataLength:param:

- (void)onMixedAudioData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param;

Callback to get the audio data played by the SDK and the audio data captured by the local microphone. The audio data is the data mixed by the SDK.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.

Details

The audio data played by the SDK is mixed with the data captured by the local microphone before being sent to the speaker, and is called back through this function. When to trigger: On the premise of calling [setAudioDataHandler] to set the listener callback, after calling [startAudioDataObserver] to set the mask 0x04, this callback will be triggered only when it is in the publishing stream state or playing stream state.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: When playing copyrighted music, this callback will be disabled by default. If necessary, please contact ZEGO technical support.

onPlayerAudioData:dataLength:param:streamID:

- (void)onPlayerAudioData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param streamID:(NSString *) streamID;

The callback for obtaining the audio data of each stream.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.
streamID	NSString *	Corresponding stream ID.

Details

This function will call back the data corresponding to each playing stream. Different from [onPlaybackAudioData], the latter is the mixed data of all playing streams. If developers need to process a piece of data separately, they can use this callback. When to trigger: On the premise of calling [setAudioDataHandler] to set up listening for this callback, calling [startAudioDataObserver] to set the mask 0x08 that is 1 << 3, and this callback will be triggered when the SDK audio and video engine starts to play the stream.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: None.

ZegoAudioEffectPlayerEventHandler

Declared in ZegoExpressEventHandler.h

Methods

audioEffectPlayer:audioEffectID:playStateUpdate:errorCode

- (void)audioEffectPlayer:(ZegoAudioEffectPlayer *)audioEffectPlayer audioEffectID:(unsigned int)audioEffectID playStateUpdate:(ZegoAudioEffectPlayState)state errorCode:(int)errorCode;

Audio effect playback state callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
audioEffectPlayer	ZegoAudioEffectPlayer *	Audio effect player instance that triggers this callback.
audioEffectID	unsigned int	The ID of the audio effect resource that triggered this callback.
state	ZegoAudioEffectPlayState	The playback state of the audio effect.
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.

Details

This callback is triggered when the playback state of a audio effect of the audio effect player changes.

Trigger: This callback is triggered when the playback status of the audio effect changes.

Available since: 1.16.0
Restrictions: None.

ZegoAudioMixingHandler

Declared in ZegoExpressEventHandler.h

Methods

onAudioMixingCopyData:

- (ZegoAudioMixingData *)onAudioMixingCopyData:(unsigned int) expectedDataLength;

Audio mixing callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
expectedDataLength	unsigned int	Expected length of incoming audio mixing data.

Details

The callback for copying audio data to the SDK for audio mixing. This function should be used together with [enableAudioMixing].

Use cases: Developers can use this function when they need to mix their own songs, sound effects or other audio data into the publishing stream. When to trigger: It will triggered after [createEngine], and call [enableAudioMixing] turn on audio mixing, and call [setAudioMixingHandler] set audio mixing callback handler.
Caution: This callback is a high frequency callback. To ensure the quality of the mixing data, please do not handle time-consuming operations in this callback.

Available since: 1.9.0
Restrictions: Supports 16k 32k 44.1k 48k sample rate, mono or dual channel, 16-bit deep PCM audio data.

Return

The audio data provided by the developer that is expected to be mixed into the publishing stream.

ZegoCustomAudioProcessHandler

Declared in ZegoExpressEventHandler.h

Methods

onProcessCapturedAudioData:dataLength:param:timestamp:

- (void)onProcessCapturedAudioData:(unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param timestamp:(double) timestamp;

Custom audio processing local captured PCM audio frame callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.
timestamp	double	The audio frame timestamp, starting from 0 when capture is started, the unit is milliseconds.

Details

In this callback, you can receive the PCM audio frames captured locally after used headphone monitor. Developers can modify the audio frame data, as well as the audio channels and sample rate. The timestamp can be used for data synchronization, such as lyrics, etc. If you need the data after used headphone monitor, please use the [onProcessCapturedAudioDataAfterUsedHeadphoneMonitor] callback. When to trigger: You need to call [enableCustomAudioCaptureProcessing] to enable the function first, and call [startPreview] or [startPublishingStream] to trigger this callback function.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: None.

onProcessCapturedAudioDataAfterUsedHeadphoneMonitor:dataLength:param:timestamp:

- (void)onProcessCapturedAudioDataAfterUsedHeadphoneMonitor:(unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param timestamp:(double) timestamp;

Custom audio processing local captured PCM audio frame callback after used headphone monitor.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull	Audio data in PCM format
dataLength	unsigned int	Length of the data
param	ZegoAudioFrameParam *	Parameters of the audio frame
timestamp	double	The audio frame timestamp, starting from 0 when capture is started, the unit is milliseconds.

Details

In this callback, you can receive the PCM audio frames captured locally after used headphone monitor. Developers can modify the audio frame data, as well as the audio channels and sample rate. The timestamp can be used for data synchronization, such as lyrics, etc. When to trigger: You need to call [enableCustomAudioCaptureProcessingAfterHeadphoneMonitor] to enable the function first, and call [startPreview] or [startPublishingStream] to trigger this callback function.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

onAlignedAudioAuxData:dataLength:param:

- (void)onAlignedAudioAuxData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param;

Aligned audio aux frames callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.

Details

In this callback, you can receive the audio aux frames which aligned with accompany. Developers can record locally. When to trigger: This callback function will not be triggered until [enableAlignedAudioAuxData] is called to turn on the function and [startpublishingstream] or [startrecordingcaptureddata] is called.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback, and the data in this callback cannot be modified.

Restrictions: To obtain audio aux data of the media player from this callback, developers need to call [enableAux] and [start] of MediaPlayer.

onBeforeAudioPrepAudioData:dataLength:param:

- (void)onBeforeAudioPrepAudioData:(const unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param;

Audio data callback before SDK internal audio preprocessing.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	const unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.

Details

In this callback, you can receive the audio data before SDK internal audio preprocessing. When to trigger: This callback function will not be triggered until [enableBeforeAudioPrepAudioData] is called to turn on the function and [startpublishingstream] is called.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback, and the data in this callback cannot be modified.

Restrictions: None.

onProcessRemoteAudioData:dataLength:param:streamID:timestamp:

- (void)onProcessRemoteAudioData:(unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param streamID:(NSString *) streamID timestamp:(double) timestamp;

Custom audio processing remote playing stream PCM audio frame callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.
streamID	NSString *	Corresponding stream ID.
timestamp	double	The audio frame timestamp, starting from 0 when capture is started, the unit is milliseconds.

Details

In this callback, you can receive the PCM audio frames of remote playing stream. Developers can modify the audio frame data, as well as the audio channels and sample rate. The timestamp can be used for data synchronization, such as lyrics, etc. When to trigger: You need to call [enableCustomAudioRemoteProcessing] to enable the function first, and call [startPlayingStream] to trigger this callback function.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: None.

onProcessPlaybackAudioData:dataLength:param:timestamp:

- (void)onProcessPlaybackAudioData:(unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoAudioFrameParam *) param timestamp:(double) timestamp;

Custom audio processing SDK playback PCM audio frame callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull	Audio data in PCM format.
dataLength	unsigned int	Length of the data.
param	ZegoAudioFrameParam *	Parameters of the audio frame.
timestamp	double	The audio frame timestamp, starting from 0 when capture is started, the unit is milliseconds (It is effective when there is one and only one stream).

Details

In this callback, you can receive the SDK playback PCM audio frame. Developers can modify the audio frame data, as well as the audio channels and sample rate. The timestamp can be used for data synchronization, such as lyrics, etc. When to trigger: You need to call [enableCustomAudioPlaybackProcessing] to enable the function first, and call [startPublishingStream], [startPlayingStream], [startPreview], [createMediaPlayer] or [createAudioEffectPlayer] to trigger this callback function.

Caution: This callback is a high-frequency callback, please do not perform time-consuming operations in this callback.

Restrictions: None.

ZegoCustomVideoCaptureHandler

Declared in ZegoExpressEventHandler.h

Methods

onStart:

- (void)onStart:(ZegoPublishChannel) channel;

Customize the notification of the start of video capture.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.

Details

The SDK informs that the video frame is about to be collected, and the video frame data sent to the SDK is valid after receiving the callback.

Use cases: Live data collected by non-cameras. For example, local video file playback, screen sharing, game live broadcast, etc. When to
Trigger: After calling [startPreview] or [startPublishingStream] successfully.
Caution: The video frame data sent to the SDK after receiving the callback is valid.
Related callbacks: Customize the end of capture notification [onCaptureStop].
Related APIs: Call [setCustomVideoCaptureHandler] to set custom video capture callback.

Available since: 1.1.0

onStop:

- (void)onStop:(ZegoPublishChannel) channel;

Customize the notification of the end of the collection.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.

Details

The SDK informs that it is about to end the video frame capture.

Use cases: Live data collected by non-cameras. For example, local video file playback, screen sharing, game live broadcast, etc. When to
Trigger: After calling [stopPreview] or [stopPublishingStream] successfully.
Caution: If you call [startPreview] and [startPublishingStream] to start preview and push stream at the same time after you start custom capture, you should call [stopPreview] and [stopPublishingStream] to stop the preview and push stream before triggering the callback.
Related callbacks: Custom video capture start notification [onCaptureStart].
Related APIs: Call [setCustomVideoCaptureHandler] to set custom video capture callback.

Available since: 1.1.0

onEncodedDataTrafficControl:channel:

- (void)onEncodedDataTrafficControl:(ZegoTrafficControlInfo *) trafficControlInfo channel:(ZegoPublishChannel) channel;

When network changes are detected during custom video capture, the developer is notified that traffic control is required, and the encoding configuration is adjusted according to the recommended parameters of the SDK.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
trafficControlInfo	ZegoTrafficControlInfo *	traffic control info.
channel	ZegoPublishChannel	Publishing stream channel.

Details

When using custom video capture, the SDK detects a network change, informs the developer that it needs to do flow control, and adjust the encoding configuration according to the recommended parameters of the SDK. In the case of custom collection and transmission of encoded data, the SDK cannot know the external encoding configuration, so the flow control operation needs to be completed by the developer. The SDK will notify the developer of the recommended value of the video configuration according to the current network situation, and the developer needs to modify the encoder configuration by himself to ensure the smoothness of video transmission.

Use cases: Live data collected by non-cameras. For example, local video file playback, screen sharing, game live broadcast, etc. When to
Trigger: When network status changes during the process of custom video capture and flow control is required.
Caution: Please do not perform time-consuming operations in this callback, such as reading and writing large files. If you need to perform time-consuming operations, please switch threads.
Related APIs: Call [setCustomVideoCaptureHandler] to set custom video capture callback.

Available since: 1.14.0

ZegoCustomVideoProcessHandler

Declared in ZegoExpressEventHandler.h

Methods

onStart:

- (void)onStart:(ZegoPublishChannel) channel;

The SDK informs the developer that it is about to start custom video processing.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.

Details

When the custom video pre-processing is turned on, the SDK informs the developer that the video pre-processing is about to start, and it is recommended to initialize other resources(E.g. Beauty SDK) in this callback.

Use cases: After the developer collects the video data by himself or obtains the video data collected by the SDK, if the basic beauty and watermark functions of the SDK cannot meet the needs of the developer (for example, the beauty effect cannot meet the expectations), the ZegoEffects SDK can be used to perform the video Some special processing, such as beautifying, adding pendants, etc., this process is the pre-processing of custom video. When to
Trigger: Open custom video pre-processing, after calling [startPreview] or [startPublishingStream] successfully.
Related callbacks: Custom video pre-processing end notification [onStop].
Related APIs: Call [setCustomVideoProcessHandler] function to set custom video pre-processing callback.

Available since: 2.2.0

onStop:

- (void)onStop:(ZegoPublishChannel) channel;

The SDK informs the developer to stop custom video processing.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.

Details

When the custom video pre-processing is turned on, the SDK informs the developer that the video pre-processing is about to end, and it is recommended to destroy other resources(E.g. Beauty SDK) in this callback.

Use cases: After the developer collects the video data by himself or obtains the video data collected by the SDK, if the basic beauty and watermark functions of the SDK cannot meet the needs of the developer (for example, the beauty effect cannot meet the expectations), the ZegoEffects SDK can be used to perform the video Some special processing, such as beautifying, adding pendants, etc., this process is the pre-processing of custom video. When to
Trigger: If you call [startPreview] to start the preview and [startPublishingStream] to start the push stream at the same time after you start the custom capture, you should call [stopPreview] to stop the preview and [stopPublishingStream] to stop the push stream before the callback will be triggered.
Related callbacks: Custom video pre-processing start notification [onStart].
Related APIs: Call [setCustomVideoProcessHandler] function to set custom video pre-processing callback.

Available since: 2.2.0

onCapturedUnprocessedCVPixelBuffer:timestamp:channel:

- (void)onCapturedUnprocessedCVPixelBuffer:(CVPixelBufferRef) buffer timestamp:(CMTime) timestamp channel:(ZegoPublishChannel) channel;

Call back when the original video data of type [CVPixelBuffer] is obtained.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
buffer	CVPixelBufferRef	CVPixelBuffer type video frame data to be sent to the SDK.
timestamp	CMTime	Timestamp of this video frame.
channel	ZegoPublishChannel	Publishing stream channel.

Details

When the custom video pre-processing is turned on, after calling [setCustomVideoProcessHandler] to set the callback, the SDK receives the original video data and calls back to the developer. After the developer has processed the original image, he must call [sendCustomVideoProcessedCVPixelbuffer] to send the processed data back to the SDK, otherwise it will cause frame loss.

Use cases: After the developer collects the video data by himself or obtains the video data collected by the SDK, if the basic beauty and watermark functions of the SDK cannot meet the needs of the developer (for example, the beauty effect cannot meet the expectations), the ZegoEffects SDK can be used to perform the video Some special processing, such as beautifying, adding pendants, etc., this process is the pre-processing of custom video. When to
Trigger: When the custom video pre-processing is enabled, the SDK collects the original video data.
Platform differences: It only takes effect on the iOS/macOS platform.

Available since: 2.2.0
Restrictions: This interface takes effect when [enableCustomVideoProcessing] is called to enable custom video pre-processing and the bufferType of config is passed in [ZegoVideoBufferTypeCVPixelBuffer] or [ZegoVideoBufferTypeNV12CVPixelBuffer].

ZegoCustomVideoRenderHandler

Declared in ZegoExpressEventHandler.h

Methods

onCapturedVideoFrameRawData:dataLength:param:flipMode:channel:

- (void)onCapturedVideoFrameRawData:(unsigned char * _Nonnull * _Nonnull) data dataLength:(unsigned int *) dataLength param:(ZegoVideoFrameParam *) param flipMode:(ZegoVideoFlipMode) flipMode channel:(ZegoPublishChannel) channel;

When custom video rendering is enabled, the original video frame data collected by the local preview is called back.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull * _Nonnull	Raw video frame data (eg: RGBA only needs to consider data[0], I420 needs to consider data[0,1,2]).
dataLength	unsigned int *	Data length (eg: RGBA only needs to consider dataLength[0], I420 needs to consider dataLength[0,1,2]).
param	ZegoVideoFrameParam *	Video frame parameters.
flipMode	ZegoVideoFlipMode	video flip mode.
channel	ZegoPublishChannel	Publishing stream channel.

Details

When using custom video rendering, the SDK callbacks the original video frame data collected by the local preview, which is rendered by the developer.

Use cases: Use a cross-platform interface framework or game engine; need to obtain the video frame data collected or streamed by the SDK for special processing. When to
Trigger: When the local preview is turned on, when the SDK collects the local preview video frame data.
Related APIs: Call [setCustomVideoRenderHandler] to set custom video rendering callback.

Available since: 1.1.0

onRemoteVideoFrameRawData:dataLength:param:streamID:

- (void)onRemoteVideoFrameRawData:(unsigned char * _Nonnull * _Nonnull) data dataLength:(unsigned int *) dataLength param:(ZegoVideoFrameParam *) param streamID:(NSString *) streamID;

When custom video rendering is enabled, the remote end pulls the original video frame data to call back, and distinguishes different streams by streamID.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull * _Nonnull	Raw video frame data (eg: RGBA only needs to consider data[0], I420 needs to consider data[0,1,2]).
dataLength	unsigned int *	Data length (eg: RGBA only needs to consider dataLength[0], I420 needs to consider dataLength[0,1,2]).
param	ZegoVideoFrameParam *	Video frame parameters.
streamID	NSString *	Stream ID.

Details

When custom video rendering is enabled, the SDK calls back the remote end to pull the original video frame data, distinguishes different streams by streamID, and renders them by the developer.

Use cases: Use a cross-platform interface framework or game engine; need to obtain the video frame data collected or streamed by the SDK for special processing. When to
Trigger: After starting to stream, when the SDK receives the video frame data of the remote stream.
Related APIs: Call [setCustomVideoRenderHandler] to set custom video rendering callback.

Available since: 1.1.0

onCapturedVideoFrameCVPixelBuffer:param:flipMode:channel:

- (void)onCapturedVideoFrameCVPixelBuffer:(CVPixelBufferRef) buffer param:(ZegoVideoFrameParam *) param flipMode:(ZegoVideoFlipMode) flipMode channel:(ZegoPublishChannel) channel;

Custom video rendering local preview video frame CVPixelBuffer data callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
buffer	CVPixelBufferRef	Video frame data in CVPixelBufferRef
param	ZegoVideoFrameParam *	Video frame param.
flipMode	ZegoVideoFlipMode	video flip mode.
channel	ZegoPublishChannel	Publishing stream channel.

Details

When [enableCustomVideoRender] is called to enable custom video rendering and the specified data type is [CVPixelBuffer], this function will be called back with the local preview video frame CVPixelBufferRef data.

Use cases: Scenes that need to obtain video frame data captured by the SDK for special processing, such as cross-platform UI frameworks, game engines, etc.. When to
Trigger: After calling [startPreview], the SDK will call back when the local preview video frame data is captured.
Related APIs: Call [setCustomVideoRenderHandler] to set custom video rendering callback.
Platform differences: Only for iOS and macOS.

Available since: 1.1.0

onRemoteVideoFrameCVPixelBuffer:param:streamID:

- (void)onRemoteVideoFrameCVPixelBuffer:(CVPixelBufferRef) buffer param:(ZegoVideoFrameParam *) param streamID:(NSString *) streamID;

Custom video rendering remote playing stream video frame CVPixelBuffer data callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
buffer	CVPixelBufferRef	Video frame data in CVPixelBufferRef
param	ZegoVideoFrameParam *	Video frame param.
streamID	NSString *	Stream ID.

Details

When [enableCustomVideoRender] is called to enable custom video rendering and the specified data type is [CVPixelBuffer], this function will be called back with the remote playing stream video frame CVPixelBufferRef data.

Use cases: Scenes that need to obtain the video frame data of the SDK remote playing stream for special processing, such as using a cross-platform UI framework, game engine, etc. When to
Trigger: After calling [startPlayingStream], the SDK will call back when the remote streaming video frame data is received.
Related APIs: Call [setCustomVideoRenderHandler] to set custom video rendering callback.
Platform differences: Only for iOS and macOS.

Available since: 1.1.0

onRemoteVideoFrameEncodedData:dataLength:param:referenceTimeMillisecond:streamID:

- (void)onRemoteVideoFrameEncodedData:(unsigned char * _Nonnull) data dataLength:(unsigned int) dataLength param:(ZegoVideoEncodedFrameParam *) param referenceTimeMillisecond:(unsigned long long) referenceTimeMillisecond streamID:(NSString *) streamID;

Custom video rendering remote playing stream video frame undecoded data callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	unsigned char * _Nonnull	Encoded data of video frames.
dataLength	unsigned int	Data length.
param	ZegoVideoEncodedFrameParam *	Video frame parameters.
referenceTimeMillisecond	unsigned long long	video frame reference time, UNIX timestamp, in milliseconds.
streamID	NSString *	Stream ID.

Details

When [enableCustomVideoRender] is called to enable custom video rendering and the specified data type is [EncodedData], this function will be called back with the remote playing stream undecoded video frame data. When to

Trigger: After calling [startPlayingStream], the SDK will call back when the remote streaming video frame data is received.
Related APIs: Call [setCustomVideoRenderHandler] to set custom video rendering callback.

Available since: 1.10.0

ZegoDataRecordEventHandler

Declared in ZegoExpressEventHandler.h

Methods

onCapturedDataRecordStateUpdate:errorCode:config:channel:

- (void)onCapturedDataRecordStateUpdate:(ZegoDataRecordState) state errorCode:(int) errorCode config:(ZegoDataRecordConfig *) config channel:(ZegoPublishChannel) channel;

The callback triggered when the state of data recording (to a file) changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoDataRecordState	File recording status.
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
config	ZegoDataRecordConfig *	Record config.
channel	ZegoPublishChannel	Publishing stream channel.

Details

The callback triggered when the state of data recording (to a file) changes.

Use cases: The developer should use this callback to determine the status of the file recording or for UI prompting. When to trigger: After [startRecordingCapturedData] is called, if the state of the recording process changes, this callback will be triggered.

Available since: 1.10.0
Restrictions: None.

onCapturedDataRecordProgressUpdate:config:channel:

- (void)onCapturedDataRecordProgressUpdate:(ZegoDataRecordProgress *) progress config:(ZegoDataRecordConfig *) config channel:(ZegoPublishChannel) channel;

The callback to report the current recording progress.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
progress	ZegoDataRecordProgress *	File recording progress, which allows developers to hint at the UI, etc.
config	ZegoDataRecordConfig *	Record config.
channel	ZegoPublishChannel	Publishing stream channel.

Details

Recording progress update callback, triggered at regular intervals during recording.

Use cases: Developers can do UI hints for the user interface. When to trigger: After [startRecordingCapturedData] is called, If configured to require a callback, timed trigger during recording.

Available since: 1.10.0
Restrictions: None.

ZegoEventHandler

Declared in ZegoExpressEventHandler.h

Methods

onDebugError:funcName:info:

- (void)onDebugError:(int) errorCode funcName:(NSString *) funcName info:(NSString *) info;

The callback for obtaining debugging error information.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
funcName	NSString *	Function name.
info	NSString *	Detailed error information.

Details

When the SDK functions are not used correctly, the callback prompts for detailed error information.

Trigger: Notify the developer when an exception occurs in the SDK.
Caution: None.

Available since: 1.1.0
Restrictions: None.

onEngineStateUpdate:

- (void)onEngineStateUpdate:(ZegoEngineState) state;

The callback triggered when the audio/video engine state changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoEngineState	The audio/video engine state.

Details

Callback notification of audio/video engine status update. When audio/video functions are enabled, such as preview, push streaming, local media player, audio data observering, etc., the audio/video engine will enter the start state. When you exit the room or disable all audio/video functions , The audio/video engine will enter the stop state.

Trigger: The developer called the relevant function to change the state of the audio and video engine. For example: 1. Called ZegoExpressEngine's [startPreview], [stopPreview], [startPublishingStream], [stopPublishingStream], [startPlayingStream], [stopPlayingStream], [startAudioDataObserver], [stopAudioDataObserver] and other functions. 2. The related functions of MediaPlayer are called. 3. The [LogoutRoom] function was called. 4. The related functions of RealTimeSequentialDataManager are called.
Caution: 1. When the developer calls [destroyEngine], this notification will not be triggered because the resources of the SDK are completely released. 2. If there is no special need, the developer does not need to pay attention to this callback.

Available since: 1.1.0
Restrictions: None.

onRecvExperimentalAPI:

- (void)onRecvExperimentalAPI:(NSString *) content;

Experimental API callback

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
content	NSString *	Callback content in JSON string format.

Details

Receive experimental API callbacks in JSON string format.

Caution: Please use this feature with the help of ZEGO Technical Support.

Available since: 2.7.0

onFatalError:

- (void)onFatalError:(int) errorCode;

The callback that triggered a fatal error, causing the SDK to malfunction and unable to function properly.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code.

Details

The callback that triggered a fatal error.

Trigger: The APP has enabled the restriction of access from foreign IP addresses, and the current client is outside of the domain.
Caution: None.

Available since: 3.6.0
Restrictions: None.

onRoomStateUpdate:errorCode:extendedData:roomID:

- (void)onRoomStateUpdate:(ZegoRoomState) state errorCode:(int) errorCode extendedData:(nullable NSDictionary *) extendedData roomID:(NSString *) roomID;

Notification of the room connection state changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoRoomState	Changed room state.
errorCode	int	Error code, For details, please refer to Common Error Codes.
extendedData	nullable NSDictionary *	Extended Information with state updates. When the room login is successful, the key "room_session_id" can be used to obtain the unique RoomSessionID of each audio and video communication, which identifies the continuous communication from the first user in the room to the end of the audio and video communication. It can be used in scenarios such as call quality scoring and call problem diagnosis.
roomID	NSString *	Room ID, a string of up to 128 bytes in length.

Details

This callback is triggered when the connection status of the room changes, and the reason for the change is notified.For versions 2.18.0 and above, it is recommended to use the onRoomStateChanged callback instead of the onRoomStateUpdate callback to monitor room state changes.

Use cases: Developers can use this callback to determine the status of the current user in the room. When to trigger:

The developer will receive this notification when calling the [loginRoom], [logoutRoom], [switchRoom] functions.
This notification may also be received when the network condition of the user's device changes (SDK will automatically log in to the room when disconnected, please refer to [Does ZEGO SDK support a fast reconnection for temporary disconnection] for details](https://docs.zegocloud.com/faq/reconnect?product=ExpressVideo&platform=all).

Caution: If the connection is being requested for a long time, the general probability is that the user's network is unstable.
Related APIs: [loginRoom]、[logoutRoom]、[switchRoom]

Available since: 1.1.0
Restrictions: None.

onRoomStateChanged:errorCode:extendedData:roomID:

- (void)onRoomStateChanged:(ZegoRoomStateChangedReason) reason errorCode:(int) errorCode extendedData:(NSDictionary *) extendedData roomID:(NSString *) roomID;

Notification of the room connection state changes, including specific reasons for state change.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
reason	ZegoRoomStateChangedReason	Room state change reason.
errorCode	int	Error code, please refer to the error codes document https://doc-en.zego.im/en/5548.html for details.
extendedData	NSDictionary *	Extended Information with state updates. When the room login is successful, the key "room_session_id" can be used to obtain the unique RoomSessionID of each audio and video communication, which identifies the continuous communication from the first user in the room to the end of the audio and video communication. It can be used in scenarios such as call quality scoring and call problem diagnosis.
roomID	NSString *	Room ID, a string of up to 128 bytes in length.

Details

Use cases: Developers can use this callback to determine the status of the current user in the room. When to trigger: Users will receive this notification when they call room functions (refer to [Related APIs]). 2. This notification may also be received when the user device's network conditions change (SDK will automatically log in to the room again when the connection is disconnected, refer to https://doc-zh.zego.im/faq/reconnect ).
Caution: If the connection is being requested for a long time, the general probability is that the user's network is unstable.
Related APIs: [loginRoom], [logoutRoom], [switchRoom]

Available since: 2.18.0
Restrictions: None.

onRoomUserUpdate:userList:roomID:

- (void)onRoomUserUpdate:(ZegoUpdateType) updateType userList:(NSArray<ZegoUser *> *) userList roomID:(NSString *) roomID;

The callback triggered when the number of other users in the room increases or decreases.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
updateType	ZegoUpdateType	Update type (add/delete).
userList	NSArray<ZegoUser >	List of users changed in the current room.
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

When other users in the room are online or offline, which causes the user list in the room to change, the developer will be notified through this callback.

Use cases: Developers can use this callback to update the user list display in the room in real time. When to trigger:
1. When the user logs in to the room for the first time, if there are other users in the room, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeAdd], and userList is the other users in the room at this time.
2. The user is already in the room. If another user logs in to the room through the [loginRoom] or [switchRoom] functions, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeAdd].
3. If other users log out of this room through the [logoutRoom] or [switchRoom] functions, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeDelete].
4. The user is already in the room. If another user is kicked out of the room from the server, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeDelete].
Related APIs: [loginRoom]、[logoutRoom]、[switchRoom]

Available since: 1.1.0
Restrictions: If developers need to use ZEGO room users notifications, please ensure that the [ZegoRoomConfig] sent by each user when logging in to the room has the [isUserStatusNotify] property set to true, otherwise the callback notification will not be received.

onRoomOnlineUserCountUpdate:roomID:

- (void)onRoomOnlineUserCountUpdate:(int) count roomID:(NSString *) roomID;

The callback triggered every 30 seconds to report the current number of online users.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
count	int	Count of online users.
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

This method will notify the user of the current number of online users in the room.

Use cases: Developers can use this callback to show the number of user online in the current room.
When to call /Trigger: After successfully logging in to the room.
Caution: 1. This function is called back every 30 seconds. 2. Because of this design, when the number of users in the room exceeds 500, there will be some errors in the statistics of the number of online people in the room.

Available since: 1.7.0
Restrictions: None.

onRoomStreamUpdate:streamList:extendedData:roomID:

- (void)onRoomStreamUpdate:(ZegoUpdateType) updateType streamList:(NSArray<ZegoStream *> *) streamList extendedData:(nullable NSDictionary *) extendedData roomID:(NSString *) roomID;

The callback triggered when the number of streams published by the other users in the same room increases or decreases.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
updateType	ZegoUpdateType	Update type (add/delete).
streamList	NSArray<ZegoStream >	Updated stream list.
extendedData	nullable NSDictionary *	Extended information with stream updates.When receiving a stream deletion notification, the developer can convert the string into a json object to get the stream_delete_reason field, which is an array of stream deletion reasons, and the stream_delete_reason[].code field may have the following values: 1 (the user actively stops publishing stream) ; 2 (user heartbeat timeout); 3 (user repeated login); 4 (user kicked out); 5 (user disconnected); 6 (removed by the server).
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

When other users in the room start publishing stream or stop publishing stream, the streaming list in the room changes, and the developer will be notified through this callback.

Use cases: This callback is used to monitor stream addition or stream deletion notifications of other users in the room. Developers can use this callback to determine whether other users in the same room start or stop publishing stream, so as to achieve active playing stream [startPlayingStream] or take the initiative to stop the playing stream [stopPlayingStream], and use it to change the UI controls at the same time. When to trigger:
1. When the user logs in to the room for the first time, if there are other users publishing streams in the room, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeAdd], and streamList is an existing stream list.
2. The user is already in the room. if another user adds a new push, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeAdd].
3. The user is already in the room. If other users stop streaming, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeDelete].
4. The user is already in the room. If other users leave the room, the SDK will trigger a callback notification with updateType being [ZegoUpdateTypeDelete].

Available since: 1.1.0
Restrictions: None.

onRoomStreamExtraInfoUpdate:roomID:

- (void)onRoomStreamExtraInfoUpdate:(NSArray<ZegoStream *> *) streamList roomID:(NSString *) roomID;

The callback triggered when there is an update on the extra information of the streams published by other users in the same room.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamList	NSArray<ZegoStream >	List of streams that the extra info was updated.
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

All users in the room will be notified by this callback when the extra information of the stream in the room is updated.

Use cases: Users can realize some business functions through the characteristics of stream extra information consistent with stream life cycle.
When to call /Trigger: When a user publishing the stream update the extra information of the stream in the same room, other users in the same room will receive the callback.
Caution: Unlike the stream ID, which cannot be modified during the publishing process, the stream extra information can be updated during the life cycle of the corresponding stream ID.
Related APIs: Users who publish stream can set extra stream information through [setStreamExtraInfo].

Available since: 1.1.0
Restrictions: None.

onRoomExtraInfoUpdate:roomID:

- (void)onRoomExtraInfoUpdate:(NSArray<ZegoRoomExtraInfo *> *) roomExtraInfoList roomID:(NSString *) roomID;

The callback triggered when there is an update on the extra information of the room.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
roomExtraInfoList	NSArray<ZegoRoomExtraInfo >	List of the extra info updated.
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

After the room extra information is updated, all users in the room will be notified except update the room extra information user.

Use cases: Extra information for the room.
When to call /Trigger: When a user update the room extra information, other users in the same room will receive the callback.
Related APIs: Users can update room extra information through [setRoomExtraInfo] function.

Available since: 1.1.0
Restrictions: None.

onRoomTokenWillExpire:roomID:

- (void)onRoomTokenWillExpire:(int) remainTimeInSecond roomID:(NSString *) roomID;

Callback notification that room Token authentication is about to expire.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
remainTimeInSecond	int	The remaining time before the token expires.
roomID	NSString *	Room ID where the user is logged in, a string of up to 128 bytes in length.

Details

The callback notification that the room Token authentication is about to expire, please use [renewToken] to update the room Token authentication.

Use cases: In order to prevent illegal entry into the room, it is necessary to perform authentication control on login room, push streaming, etc., to improve security.
When to call /Trigger: 30 seconds before the Token expires, the SDK will call [onRoomTokenWillExpire] to notify developer.
Caution: The token contains important information such as the user's room permissions, publish stream permissions, and effective time, please refer to https://docs.zegocloud.com/article/11649.
Related APIs: When the developer receives this callback, he can use [renewToken] to update the token authentication information.

Available since: 2.8.0
Restrictions: None.

onPublisherStateUpdate:errorCode:extendedData:streamID:

- (void)onPublisherStateUpdate:(ZegoPublisherState) state errorCode:(int) errorCode extendedData:(nullable NSDictionary *) extendedData streamID:(NSString *) streamID;

The callback triggered when the state of stream publishing changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoPublisherState	State of publishing stream.
errorCode	int	The error code corresponding to the status change of the publish stream, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
extendedData	nullable NSDictionary *	Extended information with state updates, include playing stream CDN address.
streamID	NSString *	Stream ID.

Details

After calling the [startPublishingStream] successfully, the notification of the publish stream state change can be obtained through the callback function. You can roughly judge the user's uplink network status based on whether the state parameter is in [PUBLISH_REQUESTING].

Caution: The parameter [extendedData] is extended information with state updates. If you use ZEGO's CDN content distribution network, after the stream is successfully published, the keys of the content of this parameter are [flv_url_list], [rtmp_url_list], [hls_url_list], these correspond to the publishing stream URLs of the flv, rtmp, and hls protocols.
Related callbacks: After calling the [startPlayingStream] successfully, the notification of the play stream state change can be obtained through the callback function [onPlayerStateUpdate]. You can roughly judge the user's downlink network status based on whether the state parameter is in [PLAY_REQUESTING].

Available since: 1.1.0

onPublisherQualityUpdate:streamID:

- (void)onPublisherQualityUpdate:(ZegoPublishStreamQuality *) quality streamID:(NSString *) streamID;

Callback for current stream publishing quality.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
quality	ZegoPublishStreamQuality *	Publishing stream quality, including audio and video framerate, bitrate, RTT, etc.
streamID	NSString *	Stream ID.

Details

After calling the [startPublishingStream] successfully, the callback will be received every 3 seconds default(If you need to change the time, please contact the instant technical support to configure). Through the callback, the collection frame rate, bit rate, RTT, packet loss rate and other quality data of the published audio and video stream can be obtained, and the health of the publish stream can be monitored in real time.You can monitor the health of the published audio and video streams in real time according to the quality parameters of the callback function, in order to show the uplink network status in real time on the device UI.

Caution: If you does not know how to use the parameters of this callback function, you can only pay attention to the [level] field of the [quality] parameter, which is a comprehensive value describing the uplink network calculated by SDK based on the quality parameters.
Related callbacks: After calling the [startPlayingStream] successfully, the callback [onPlayerQualityUpdate] will be received every 3 seconds. You can monitor the health of play streams in real time based on quality data such as frame rate, code rate, RTT, packet loss rate, etc.

Available since: 1.1.0

onPublisherCapturedAudioFirstFrame

- (void)onPublisherCapturedAudioFirstFrame;

The callback triggered when the first audio frame is captured.

Declared in ZegoExpressEventHandler.h

This callback will be received when the SDK starts the microphone to capture the first frame of audio data. If this callback is not received, the audio capture device is occupied or abnormal.

Trigger: When the engine of the audio/video module inside the SDK starts, the SDK will go and collect the audio data from the local device and will receive the callback at that time.
Related callbacks: Determine if the SDK actually collected video data by the callback function [onPublisherCapturedVideoFirstFrame], determine if the SDK has rendered the first frame of video data collected by calling back [onPublisherRenderVideoFirstFrame].

Available since: 1.1.0

onPublisherCapturedVideoFirstFrame:

- (void)onPublisherCapturedVideoFirstFrame:(ZegoPublishChannel) channel;

The callback triggered when the first video frame is captured.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

The SDK will receive this callback when the first frame of video data is captured. If this callback is not received, the video capture device is occupied or abnormal.

Trigger: When the SDK's internal audio/video module's engine starts, the SDK will collect video data from the local device and will receive this callback.
Related callbacks: Determine if the SDK actually collected audio data by the callback function [onPublisherCapturedAudioFirstFrame], determine if the SDK has rendered the first frame of video data collected by calling back [onPublisherRenderVideoFirstFrame].

Available since: 1.1.0

onPublisherSendAudioFirstFrame:

- (void)onPublisherSendAudioFirstFrame:(ZegoPublishChannel) channel;

The callback triggered when the first audio frame is sent.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio stream, you can ignore this parameter.

Details

After the [startPublishingStream] function is called successfully, this callback will be called when SDK received the first frame of audio data. Developers can use this callback to determine whether SDK has actually collected audio data. If the callback is not received, the audio capture device is occupied or abnormal.

Trigger: In the case of no startPublishingStream audio stream, the first startPublishingStream audio stream, it will receive this callback.
Related callbacks: After the [startPublishingStream] function is called successfully, determine if the SDK actually collected video data by the callback function [onPublisherCapturedVideoFirstFrame], determine if the SDK has rendered the first frame of video data collected by calling back [onPublisherRenderVideoFirstFrame].

Available since: 3.5.0

onPublisherSendVideoFirstFrame:

- (void)onPublisherSendVideoFirstFrame:(ZegoPublishChannel) channel;

The callback triggered when the first video frame is sent.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one video stream, you can ignore this parameter.

Details

After the [startPublishingStream] function is called successfully, this callback will be called when SDK received the first frame of video data. Developers can use this callback to determine whether SDK has actually collected video data. If the callback is not received, the video capture device is occupied or abnormal.

Trigger: In the case of no startPublishingStream video stream, the first startPublishingStream video stream, it will receive this callback.
Related callbacks: After the [startPublishingStream] function is called successfully, determine if the SDK actually collected audio data by the callback function [onPublisherCapturedAudioFirstFrame], determine if the SDK has rendered the first frame of video data collected by calling back [onPublisherRenderVideoFirstFrame].

Available since: 3.5.0

onPublisherRenderVideoFirstFrame:

- (void)onPublisherRenderVideoFirstFrame:(ZegoPublishChannel) channel;

The callback triggered when the first video frame is rendered.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

this callback will be called after SDK rendered the first frame of video data captured. This interface is for preview rendering. The first frame callback is only available for external collection and internal preview. If it is not for SDK rendering, there is no such callback.

Related callbacks: After the [startPublishingStream] function is called successfully, determine if the SDK actually collected audio data by the callback function [onPublisherCapturedAudioFirstFrame], determine if the SDK actually collected video data by the callback function [onPublisherCapturedVideoFirstFrame].

Available since: 2.4.0

onPublisherVideoSizeChanged:channel:

- (void)onPublisherVideoSizeChanged:(CGSize) size channel:(ZegoPublishChannel) channel;

The callback triggered when the video capture resolution changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
size	CGSize	Video capture resolution
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

When the audio and video stream is not published [startPublishingStream] or previewed [startPreview] for the first time, the publishing stream or preview first time, that is, the engine of the audio and video module inside the SDK is started, the video data of the local device will be collected, and the collection resolution will change at this time.

Trigger: After the successful publish [startPublishingStream], the callback will be received if there is a change in the video capture resolution in the process of publishing the stream.
Use cases: You can use this callback to remove the cover of the local preview UI and similar operations.You can also dynamically adjust the scale of the preview view based on the resolution of the callback.
Caution: What is notified during external collection is the change in encoding resolution, which will be affected by flow control.

Available since: 1.1.0

onPublisherRelayCDNStateUpdate:streamID:

- (void)onPublisherRelayCDNStateUpdate:(NSArray<ZegoStreamRelayCDNInfo *> *) infoList streamID:(NSString *) streamID;

The callback triggered when the state of relayed streaming to CDN changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
infoList	NSArray<ZegoStreamRelayCDNInfo >	List of information that the current CDN is relaying.
streamID	NSString *	Stream ID.

Details

Developers can use this callback to determine whether the audio and video streams of the relay CDN are normal. If they are abnormal, further locate the cause of the abnormal audio and video streams of the relay CDN and make corresponding disaster recovery strategies.

Trigger: After the ZEGO RTC server relays the audio and video streams to the CDN, this callback will be received if the CDN relay status changes, such as a stop or a retry.
Caution: If you do not understand the cause of the abnormality, you can contact ZEGO technicians to analyze the specific cause of the abnormality.

Available since: 1.1.0

onPublisherVideoEncoderChanged:toCodecID:channel:

- (void)onPublisherVideoEncoderChanged:(ZegoVideoCodecID) fromCodecID toCodecID:(ZegoVideoCodecID) toCodecID channel:(ZegoPublishChannel) channel;

The callback triggered when the video encoder changes in publishing stream.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
fromCodecID	ZegoVideoCodecID	Video codec ID before the change.
toCodecID	ZegoVideoCodecID	Video codec ID after the change.
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

After the H.265 automatic downgrade policy is enabled, if H.265 encoding is not supported or the encoding fails during the streaming process with H.265 encoding, the SDK will actively downgrade to the specified encoding (H.264), and this callback will be triggered at this time. When to trigger: In the process of streaming with H.265 encoding, if H.265 encoding is not supported or encoding fails, the SDK will actively downgrade to the specified encoding (H.264), and this callback will be triggered at this time.

Caution: When this callback is triggered, if local video recording or cloud recording is in progress, multiple recording files will be generated. Developers need to collect all the recording files for processing after the recording ends. When this callback is triggered, because the streaming code has changed, the developer can evaluate whether to notify the streaming end, so that the streaming end can deal with it accordingly.

Available since: 2.12.0

onPublisherStreamEvent:streamID:extraInfo:

- (void)onPublisherStreamEvent:(ZegoStreamEvent) eventID streamID:(NSString *) streamID extraInfo:(NSString *) extraInfo;

The callback triggered when publishing stream.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
eventID	ZegoStreamEvent	Publish stream event ID
streamID	NSString *	Stream ID.
extraInfo	NSString *	extra info. it is in JSON format. Included information includes "url" for address, "streamProtocol" for stream protocol, including rtmp, flv, avertp, hls, webrtc, etc. "netProtocol" for network protocol, including tcp, udp, quic, "resourceType" for resource type , including cdn, rtc, l3.

Details

After start publishing stream, this callback will return the current stream address, resource type and protocol-related information. When to trigger: Publish and retry publish events.

Caution: None.

Available since: 2.18.0

onVideoObjectSegmentationStateChanged:channel:errorCode:

- (void)onVideoObjectSegmentationStateChanged:(ZegoObjectSegmentationState) state channel:(ZegoPublishChannel) channel errorCode:(int) errorCode;

The video object segmentation state changed.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoObjectSegmentationState	Object segmentation state.
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.
errorCode	int	The error code corresponding to the status change of the object segmentation, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.

Details

The object segmentation state of the stream publishing end changes. When to trigger: When [enableVideoObjectSegmentation] enables or disables object segmentation, notify the developer whether to enable object segmentation according to the actual state.

Caution: This callback depends on enabling preview or stream publishing.

Available since: 3.4.0

onPublisherLowFpsWarning:channel:

- (void)onPublisherLowFpsWarning:(ZegoVideoCodecID) codecID channel:(ZegoPublishChannel) channel;

Video encoding low frame rate warning.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
codecID	ZegoVideoCodecID	Video codec ID.
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

Video encoding low frame rate warning. When to trigger: This callback triggered by low frame rate in video encoding.

Caution: This callback is disabled by default, if necessary, please contact ZEGO technical support.

Available since: 3.8.0

onPublisherDummyCaptureImagePathError:path:channel:

- (void)onPublisherDummyCaptureImagePathError:(int) errorCode path:(NSString *) path channel:(ZegoPublishChannel) channel;

The notification for setting the path of the static image displayed when the camera is turned off is incorrect.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	error code.
path	NSString *	Image path.
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

The notification for setting the path of the static image displayed when the camera is turned off is incorrect. When to trigger: If the path for the image is set using [setDummyCaptureImagePath], but the image cannot be obtained during streaming, this callback will be triggered.

Caution: Please make sure that the image path is correct and has read permission before setting it.

Available since: 3.9.0

onPublisherFaceDetectInfo:channel:

- (void)onPublisherFaceDetectInfo:(ZegoFaceDetectionInfo *) info channel:(ZegoPublishChannel) channel;

Face detection information update notification.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
info	ZegoFaceDetectionInfo *	Face detection information.
channel	ZegoPublishChannel	Publishing stream channel.If you only publish one audio and video stream, you can ignore this parameter.

Details

The notification for face detection. When to trigger: Turn on face detection through the [enableFaceDetection] interface, and this callback will be triggered when the camera is started or the number of faces changes.

Caution: The callback is low-frequency and cannot be used with the custom video pre-processing function.

Available since: 3.20.0

onPlayerStateUpdate:errorCode:extendedData:streamID:

- (void)onPlayerStateUpdate:(ZegoPlayerState) state errorCode:(int) errorCode extendedData:(nullable NSDictionary *) extendedData streamID:(NSString *) streamID;

The callback triggered when the state of stream playing changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoPlayerState	State of playing stream.
errorCode	int	The error code corresponding to the status change of the playing stream, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
extendedData	nullable NSDictionary *	Extended Information with state updates. As the standby, only an empty json table is currently returned.
streamID	NSString *	stream ID.

Details

After calling the [startPlayingStream] successfully, the notification of the playing stream state change can be obtained through the callback function. You can roughly judge the user's downlink network status based on whether the state parameter is in [PLAY_REQUESTING]. When to trigger: After calling the [startPublishingStream], this callback is triggered when a playing stream's state changed.

Related callbacks: After calling the [startPublishingStream] successfully, the notification of the publish stream state change can be obtained through the callback function [onPublisherStateUpdate]. You can roughly judge the user's uplink network status based on whether the state parameter is in [PUBLISH_REQUESTING].

Available since: 1.1.0

onPlayerSwitched:streamID:

- (void)onPlayerSwitched:(int) errorCode streamID:(NSString *) streamID;

Switch playing stream callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	The error code corresponding to the result of the switch stream, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.
streamID	NSString *	The stream ID currently playing.

Details

After calling the [switchPlayingStream] successfully, the result of switching streams can be obtained through this callback function. When to trigger: After calling the [switchPlayingStream], this callback is triggered when a switch stream request ultimately succeeds or fails.

Related callbacks: After the stream switching is successful or failed, you can obtain the current streaming status through the callback function [onPlayerStateUpdate].

Available since: 3.16.0

onPlayerQualityUpdate:streamID:

- (void)onPlayerQualityUpdate:(ZegoPlayStreamQuality *) quality streamID:(NSString *) streamID;

Callback for current stream playing quality.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
quality	ZegoPlayStreamQuality *	Playing stream quality, including audio and video framerate, bitrate, RTT, etc.
streamID	NSString *	Stream ID.

Details

After calling the [startPlayingStream] successfully, the callback will be received every 3 seconds default(If you need to change the time, please contact the instant technical support to configure). Through the callback, the collection frame rate, bit rate, RTT, packet loss rate and other quality data can be obtained, and the health of the played audio and video streams can be monitored in real time.

Use cases: You can monitor the health of the played audio and video streams in real time according to the quality parameters of the callback function, in order to show the downlink network status on the device UI in real time.
Caution: If you does not know how to use the various parameters of the callback function, you can only focus on the level field of the quality parameter, which is a comprehensive value describing the downlink network calculated by SDK based on the quality parameters.
Related callbacks: After calling the [startPublishingStream] successfully, a callback [onPublisherQualityUpdate] will be received every 3 seconds. You can monitor the health of publish streams in real time based on quality data such as frame rate, code rate, RTT, packet loss rate, etc.

Available since: 1.1.0

onPlayerMediaEvent:streamID:

- (void)onPlayerMediaEvent:(ZegoPlayerMediaEvent) event streamID:(NSString *) streamID;

The callback triggered when a media event occurs during streaming playing.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
event	ZegoPlayerMediaEvent	Specific events received when playing the stream.
streamID	NSString *	Stream ID.

Details

This callback is used to receive pull streaming events.

Use cases: You can use this callback to make statistics on stutters or to make friendly displays in the UI of the app. When to trigger: After calling the [startPublishingStream], this callback is triggered when an event such as audio and video jamming and recovery occurs in the playing stream.

Available since: 1.1.0

onPlayerRecvAudioFirstFrame:

- (void)onPlayerRecvAudioFirstFrame:(NSString *) streamID;

The callback triggered when the first audio frame is received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK received the first frame of audio data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: This callback is triggered when SDK receives the first frame of audio data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerRecvVideoFirstFrame] determines whether the SDK has received the video data, and the callback [onPlayerRenderVideoFirstFrame] determines whether the SDK has rendered the first frame of the received video data.

Available since: 1.1.0

onPlayerSyncRecvAudioFirstFrame:

- (void)onPlayerSyncRecvAudioFirstFrame:(NSString *) streamID;

The callback triggered when the first audio frame is received. Please do not call the SDK interface in the callback thread.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK received the first frame of audio data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: This callback is triggered when SDK receives the first frame of audio data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerSyncRecvVideoFirstFrame] determines whether the SDK has received the video data, and the callback [onPlayerSyncRecvRenderVideoFirstFrame] determines whether the SDK has rendered the first frame of the received video data.

Available since: 3.22.0

onPlayerRecvVideoFirstFrame:

- (void)onPlayerRecvVideoFirstFrame:(NSString *) streamID;

The callback triggered when the first video frame is received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK received the first frame of video data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: This callback is triggered when SDK receives the first frame of video data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerRecvAudioFirstFrame] determines whether the SDK has received the audio data, and the callback [onPlayerRenderVideoFirstFrame] determines whether the SDK has rendered the first frame of the received video data.

Available since: 1.1.0

onPlayerSyncRecvVideoFirstFrame:

- (void)onPlayerSyncRecvVideoFirstFrame:(NSString *) streamID;

The callback triggered when the first video frame is received. Please do not call the SDK interface in the callback thread.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK received the first frame of video data.

Use cases: Developer can use this callback to count time consuming that take the first frame time.
Trigger: This callback is triggered when SDK receives the first frame of video data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerSyncRecvAudioFirstFrame] determines whether the SDK has received the audio data, and the callback [onPlayerSyncRecvRenderVideoFirstFrame] determines whether the SDK has rendered the first frame of the received video data.

Available since: 3.8.0

onPlayerRenderVideoFirstFrame:

- (void)onPlayerRenderVideoFirstFrame:(NSString *) streamID;

The callback triggered when the first video frame is rendered.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK rendered the first frame of video data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: This callback is triggered when SDK rendered the first frame of video data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerRecvAudioFirstFrame] determines whether the SDK has received the audio data, and the callback [onPlayerRecvVideoFirstFrame] determines whether the SDK has received the video data.

Available since: 1.1.0

onPlayerSyncRecvRenderVideoFirstFrame:

- (void)onPlayerSyncRecvRenderVideoFirstFrame:(NSString *) streamID;

The callback triggered when the first video frame is rendered. Please do not call the SDK interface in the callback thread.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, this callback will be called when SDK rendered the first frame of video data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: This callback is triggered when SDK rendered the first frame of video data from the network.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerSyncRecvAudioFirstFrame] determines whether the SDK has received the audio data, and the callback [onPlayerSyncRecvVideoFirstFrame] determines whether the SDK has received the video data.

Available since: 3.22.0

onPlayerRenderCameraVideoFirstFrame:

- (void)onPlayerRenderCameraVideoFirstFrame:(NSString *) streamID;

Calls back when the stream playing end renders the first frame of the video from the remote camera.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.

Details

After calling the [startPlayingStream] function to pull the stream successfully, the SDK will receive this callback after pulling the stream and rendering the first frame of remote camera video data.

Use cases: Developer can use this callback to count time consuming that take the first frame time or update the UI for playing stream.
Trigger: After the remote [enableCamera] enables the camera, or after [mutePublishStreamVideo] is true and starts to send video data, the SDK will receive this callback after playing the stream and rendering the first frame of the remote camera video data.
Caution: It is only applicable when the remote end uses the camera to push the stream. Only applicable to RTC publishing and playing streaming scenarios.
Related callbacks: After a successful call to [startPlayingStream], the callback [onPlayerRecvVideoFirstFrame] determines whether the SDK has received the video data.

Available since: 3.0.0

onPlayerRenderMultiViewFirstFrame:viewContext:

- (void)onPlayerRenderMultiViewFirstFrame:(NSString *) streamID viewContext:(NSString *) viewContext;

When multiple playing canvas are set, the callback will be triggered after one view renders the first frame of the video.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.
viewContext	NSString *	Context of view.

Details

Call [startPlayingStream] to play stream and call [setPlayingCanvas] to add multiple views, this callback will be called when SDK rendered the first frame of video data.

Use cases: Developer can use this callback to update the UI for playing stream.
Trigger: The user playing the mixed stream, adds multiple views through [setPlayingCanvas], and sets the correct viewContext parameters, which will trigger this callback after the corresponding view has rendered the first frame of video data.
Related callbacks: After a successful call to [startPlayingStream], the callback function [onPlayerRecvAudioFirstFrame] determines whether the SDK has received the audio data, and the callback [onPlayerRecvVideoFirstFrame] determines whether the SDK has received the video data.

Available since: 3.21.0

onPlayerVideoSizeChanged:streamID:

- (void)onPlayerVideoSizeChanged:(CGSize) size streamID:(NSString *) streamID;

The callback triggered when the stream playback resolution changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
size	CGSize	Video decoding resolution
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, the play resolution will change when the first frame of video data is received, or when the publisher changes the encoding resolution by calling [setVideoConfig], or when the network traffic control strategies work.

Use cases: Developers can update or switch the UI components that actually play the stream based on the final resolution of the stream.
Trigger: After the [startPlayingStream] function is called successfully, this callback is triggered when the video resolution changes while playing the stream.
Caution:

If the stream is only audio data, the callback will not be triggered.
If the user enables custom video rendering of the ZegoVideoBufferTypeEncodedData type, the SDK is not responsible for video decoding and will not trigger this callback.

Available since: 1.1.0

onPlayerRecvSEI:streamID:

deprecated

- (void)onPlayerRecvSEI:(NSData *) data streamID:(NSString *) streamID;

The callback triggered when Supplemental Enhancement Information is received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	NSData *	SEI content.
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, when the remote stream sends SEI (such as directly calling [sendSEI], audio mixing with SEI data, and sending custom video capture encoded data with SEI, etc.), the local end will receive this callback.

Trigger: After the [startPlayingStream] function is called successfully, when the remote stream sends SEI, the local end will receive this callback.
Caution: 1.The customer can directly operate the UI control in this callback function.

Since the video encoder itself generates an SEI with a payload type of 5, or when a video file is used for publishing, such SEI may also exist in the video file. Therefore, if the developer needs to filter out this type of SEI, it can be before [createEngine] Call [ZegoEngineConfig.advancedConfig("unregister_sei_filter", "XXXXX")]. Among them, unregister_sei_filter is the key, and XXXXX is the uuid filter string to be set.
When [mutePlayStreamVideo] or [muteAllPlayStreamVideo] is called to set only the audio stream to be pulled, the SEI will not be received.

Available since: 1.1.0

Deprecated

It will be deprecated in version 3.4.0 and above. Please use the [onPlayerSyncRecvSEI] function instead.

onPlayerSyncRecvSEI:streamID:

- (void)onPlayerSyncRecvSEI:(NSData *) data streamID:(NSString *) streamID;

The callback triggered when Supplemental Enhancement Information is received synchronously.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	NSData *	SEI content.
streamID	NSString *	Stream ID.

Details

Trigger: After the [startPlayingStream] function is called successfully, when the remote stream sends SEI, the local end will receive this callback.
Caution:

Since the video encoder itself generates an SEI with a payload type of 5, or when a video file is used for publishing, such SEI may also exist in the video file. Therefore, if the developer needs to filter out this type of SEI, it can be before [createEngine] Call [ZegoEngineConfig.advancedConfig("unregister_sei_filter", "XXXXX")]. Among them, unregister_sei_filter is the key, and XXXXX is the uuid filter string to be set.
When [mutePlayStreamVideo] or [muteAllPlayStreamVideo] is called to set only the audio stream to be pulled, the SEI will not be received.

Available since: 3.4.0

onPlayerRecvMediaSideInfo:

- (void)onPlayerRecvMediaSideInfo:(ZegoMediaSideInfo *) info;

The callback triggered when Supplemental Enhancement Information is received synchronously.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
info	ZegoMediaSideInfo *	SEI Callback info.

Details

Trigger: After the [startPlayingStream] function is called successfully, when the remote stream sends SEI, the local end will receive this callback.
Caution: 1. Since the video encoder itself generates an SEI with a payload type of 5, or when a video file is used for publishing, such SEI may also exist in the video file. Therefore, if the developer needs to filter out this type of SEI, it can be before [createEngine] Call [ZegoEngineConfig.advancedConfig("unregister_sei_filter", "XXXXX")]. Among them, unregister_sei_filter is the key, and XXXXX is the uuid filter string to be set. 2. When [mutePlayStreamVideo] or [muteAllPlayStreamVideo] is called to set only the audio stream to be pulled, the SEI will not be received.

Available since: 3.9.0

onPlayerRecvAudioSideInfo:streamID:

- (void)onPlayerRecvAudioSideInfo:(NSData *) data streamID:(NSString *) streamID;

Receive the audio side information content of the remote stream.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
data	NSData *	Audio side information content.
streamID	NSString *	Stream ID.

Details

After the [startPlayingStream] function is called successfully, when the remote stream sends audio side information, the local end will receive this callback.

Trigger: After the [startPlayingStream] function is called successfully, when the remote stream sends audio side information, the local end will receive this callback.
Caution: 1. When [mutePlayStreamAudio] or [muteAllPlayStreamAudio] is called to set only the video stream to be pulled, the audio side information not be received. 2. Due to factors such as the network, the received data may be missing, but the order is guaranteed.
Related APIs: Send audio side information by the [sendAudioSideInfo] function.

Available since: 2.19.0

onPlayerLowFpsWarning:streamID:

- (void)onPlayerLowFpsWarning:(ZegoVideoCodecID) codecID streamID:(NSString *) streamID;

Playing stream low frame rate warning.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
codecID	ZegoVideoCodecID	Video codec ID.
streamID	NSString *	Stream ID.

Details

This callback triggered by low frame rate when playing stream. When to trigger: This callback triggered by low frame rate when playing stream.

Caution: If the callback is triggered when the user playing the h.265 stream, you can stop playing the h.265 stream and switch to play the H.264 stream.

Available since: 2.14.0

onPlayerStreamEvent:streamID:extraInfo:

- (void)onPlayerStreamEvent:(ZegoStreamEvent) eventID streamID:(NSString *) streamID extraInfo:(NSString *) extraInfo;

The callback triggered when playing stream.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
eventID	ZegoStreamEvent	Play stream event ID
streamID	NSString *	Stream ID.
extraInfo	NSString *	extra info. it is in JSON format. Included information includes "url" for address, "streamProtocol" for stream protocol, including rtmp, flv, avertp, hls, webrtc, etc. "netProtocol" for network protocol, including tcp, udp, quic, "resourceType" for resource type , including cdn, rtc, l3.

Details

After start playing stream, this callback will return the current stream address, resource type and protocol-related information. When to trigger: Play and retry play events.

Caution: None.

Available since: 2.18.0

onPlayerVideoSuperResolutionUpdate:state:errorCode:

- (void)onPlayerVideoSuperResolutionUpdate:(NSString *) streamID state:(ZegoSuperResolutionState) state errorCode:(int) errorCode;

Playing stream video super resolution enabled state changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
streamID	NSString *	Stream ID.
state	ZegoSuperResolutionState	Video super resolution state.
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.

Details

Playing stream video super resolution enabled state changes. When to trigger: When [enableVideoSuperResolution] enables or disables video super resolution, the developer will be notified whether to enable video super resolution according to the actual situation when playing stream video rendering.

Caution: None.

Available since: 3.0.0

onMixerRelayCDNStateUpdate:taskID:

- (void)onMixerRelayCDNStateUpdate:(NSArray<ZegoStreamRelayCDNInfo *> *) infoList taskID:(NSString *) taskID;

The callback triggered when the state of relayed streaming of the mixed stream to CDN changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
infoList	NSArray<ZegoStreamRelayCDNInfo >	List of information that the current CDN is being mixed.
taskID	NSString *	The mixing task ID. Value range: the length does not exceed 256. Caution: This parameter is in string format and cannot contain URL keywords, such as 'http' and '?' etc., otherwise the push and pull flow will fail. Only supports numbers, English characters and'~','!','@','$','%','^','&','*','(',')','_' ,'+','=','-','`',';',''',',','.','<','>',''.

Details

The general situation of the mixing task on the ZEGO RTC server will push the output stream to the CDN using the RTMP protocol, and the state change during the push process will be notified from the callback function.

Use cases: It is often used when multiple video images are required to synthesize a video using mixed streaming, such as education, live teacher and student images. When to trigger: After the developer calls the [startMixerTask] function to start mixing, when the ZEGO RTC server pushes the output stream to the CDN, there is a state change.
Related callbacks: Develop can get the sound update notification of each single stream in the mixed stream through [OnMixerSoundLevelUpdate].
Related APIs: Develop can start a mixed flow task through [startMixerTask].

Available since: 1.2.1
Restrictions: None.

onMixerSoundLevelUpdate:

- (void)onMixerSoundLevelUpdate:(NSDictionary<NSNumber *, NSNumber *> *) soundLevels;

The callback triggered when the sound level of any input stream changes in the stream mixing process.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevels	NSDictionary<NSNumber , NSNumber > *	The sound key-value pair of each single stream in the mixed stream, the key is the soundLevelID of each single stream, and the value is the sound value of the corresponding single stream. Value range: The value range of value is 0.0 ~ 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

Developers can use this callback to display the effect of which stream’s anchor is talking on the UI interface of the mixed stream of the audience.

Use cases: It is often used when multiple video images are required to synthesize a video using mixed streaming, such as education, live teacher and student images. When to trigger: After the developer calls the [startPlayingStream] function to start playing the mixed stream. Callback notification period is 100 ms.
Related callbacks: [OnMixerRelayCDNStateUpdate] can be used to get update notification of mixing stream repost CDN status.
Related APIs: Develop can start a mixed flow task through [startMixerTask].

Available since: 1.2.1
Restrictions: The callback is triggered every 100 ms, and the trigger frequency cannot be set.Due to the high frequency of this callback, please do not perform time-consuming tasks or UI operations in this callback to avoid stalling.

onAutoMixerSoundLevelUpdate:

- (void)onAutoMixerSoundLevelUpdate:(NSDictionary<NSString *, NSNumber *> *) soundLevels;

The callback triggered when the sound level of any input stream changes in the auto stream mixing process.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevels	NSDictionary<NSString , NSNumber > *	Sound level hash map, key is the streamID of every single stream in this mixer stream, value is the sound level value of that single stream, value ranging from 0.0 to 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

According to this callback, user can obtain the sound level information of each stream pulled during auto stream mixing.

Use cases: Often used in voice chat room scenarios.Users can use this callback to show which streamer is speaking when an audience pulls a mixed stream.
Trigger: Call [startPlayingStream] function to pull the stream.
Related APIs: Users can call [startAutoMixerTask] function to start an auto stream mixing task.Users can call [stopAutoMixerTask] function to stop an auto stream mixing task.

Available since: 2.10.0

onAudioDeviceStateChanged:updateType:deviceType:

- (void)onAudioDeviceStateChanged:(ZegoDeviceInfo *) deviceInfo updateType:(ZegoUpdateType) updateType deviceType:(ZegoAudioDeviceType) deviceType;

The callback triggered when there is a change to audio devices (i.e. new device added or existing device deleted).

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
deviceInfo	ZegoDeviceInfo *	Audio device information
updateType	ZegoUpdateType	Update type (add/delete)
deviceType	ZegoAudioDeviceType	Audio device type

Details

only for macOS; This callback is triggered when an audio device is added or removed from the system. By listening to this callback, users can update the sound collection or output using a specific device when necessary.

onAudioDeviceVolumeChanged:deviceType:deviceID:

- (void)onAudioDeviceVolumeChanged:(int) volume deviceType:(ZegoAudioDeviceType) deviceType deviceID:(NSString *) deviceID;

The callback triggered when there is a change of the volume for the audio devices.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
volume	int	audio device volume
deviceType	ZegoAudioDeviceType	Audio device type
deviceID	NSString *	Audio device ID

Details

Audio device volume change event callback. When to trigger: After calling the [startAudioDeviceVolumeMonitor] function to start the device volume monitor, and the volume of the monitored audio device changes.

Platform differences: Only supports Windows and macOS.

Available since: 1.1.0

onVideoDeviceStateChanged:updateType:

- (void)onVideoDeviceStateChanged:(ZegoDeviceInfo *) deviceInfo updateType:(ZegoUpdateType) updateType;

The callback triggered when there is a change to video devices (i.e. new device added or existing device deleted).

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
deviceInfo	ZegoDeviceInfo *	Audio device information
updateType	ZegoUpdateType	Update type (add/delete)

Details

only for macOS; This callback is triggered when a video device is added or removed from the system. By listening to this callback, users can update the video capture using a specific device when necessary.

onCapturedSoundLevelUpdate:

- (void)onCapturedSoundLevelUpdate:(NSNumber *) soundLevel;

The local captured audio sound level callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevel	NSNumber *	Locally captured sound level value, ranging from 0.0 to 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.) .

Details

The local captured audio sound level callback.

Trigger: After you start the sound level monitor by calling [startSoundLevelMonitor].
Caution: 1. The callback notification period is the parameter value set when the [startSoundLevelMonitor] is called. The callback value is the default value of 0 When you have not called the interface [startPublishingStream] and [startPreview]. 2. This callback is a high-frequency callback, and it is recommended not to do complex logic processing inside the callback.
Related APIs: Start sound level monitoring via [startSoundLevelMonitor]. Monitoring remote played audio sound level by callback [onRemoteSoundLevelUpdate]

Available since: 1.1.0

onCapturedSoundLevelInfoUpdate:

- (void)onCapturedSoundLevelInfoUpdate:(ZegoSoundLevelInfo *) soundLevelInfo;

The local captured audio sound level callback, supported vad.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevelInfo	ZegoSoundLevelInfo *	Locally captured sound level value, ranging from 0.0 to 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

The local captured audio sound level callback.

Trigger: After you start the sound level monitor by calling [startSoundLevelMonitor].
Caution: 1. The callback notification period is the parameter value set when the [startSoundLevelMonitor] is called. 2. This callback is a high-frequency callback, and it is recommended not to do complex logic processing inside the callback.
Related APIs: Start sound level monitoring via [startSoundLevelMonitor]. Monitoring remote played audio sound level by callback [onRemoteSoundLevelUpdate] or [onRemoteSoundLevelInfoUpdate].

Available since: 2.10.0

onRemoteSoundLevelUpdate:

- (void)onRemoteSoundLevelUpdate:(NSDictionary<NSString *, NSNumber *> *) soundLevels;

The remote playing streams audio sound level callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevels	NSDictionary<NSString , NSNumber > *	Remote sound level hash map, key is the streamID, value is the sound level value of the corresponding streamID, value ranging from 0.0 to 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

The remote playing streams audio sound level callback.

Trigger: After you start the sound level monitor by calling [startSoundLevelMonitor], you are in the state of playing the stream [startPlayingStream].
Caution: The callback notification period is the parameter value set when the [startSoundLevelMonitor] is called.
Related APIs: Start sound level monitoring via [startSoundLevelMonitor]. Monitoring local captured audio sound by callback [onCapturedSoundLevelUpdate] or [onCapturedSoundLevelInfoUpdate].

Available since: 1.1.0

onRemoteSoundLevelInfoUpdate:

- (void)onRemoteSoundLevelInfoUpdate:(NSDictionary<NSString *, ZegoSoundLevelInfo *> *) soundLevelInfos;

The remote playing streams audio sound level callback, supported vad.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
soundLevelInfos	NSDictionary<NSString , ZegoSoundLevelInfo > *	Remote sound level hash map, key is the streamID, value is the sound level value of the corresponding streamID, value ranging from 0.0 to 100.0 (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

The remote playing streams audio sound level callback.

Trigger: After you start the sound level monitor by calling [startSoundLevelMonitor], you are in the state of playing the stream [startPlayingStream].
Caution: The callback notification period is the parameter value set when the [startSoundLevelMonitor] is called.
Related APIs: Start sound level monitoring via [startSoundLevelMonitor]. Monitoring local captured audio sound by callback [onCapturedSoundLevelUpdate] or [onCapturedSoundLevelInfoUpdate].

Available since: 2.10.0

onCapturedAudioSpectrumUpdate:

- (void)onCapturedAudioSpectrumUpdate:(NSArray<NSNumber *> *) audioSpectrum;

The local captured audio spectrum callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
audioSpectrum	NSArray<NSNumber >	Locally captured audio spectrum value list. Spectrum value range is [0-2^30].

Details

The local captured audio spectrum callback.

Trigger: After you start the audio spectrum monitor by calling [startAudioSpectrumMonitor].
Caution: The callback notification period is the parameter value set when the [startAudioSpectrumMonitor] is called. The callback value is the default value of 0 When you have not called the interface [startPublishingStream] and [startPreview].
Related APIs: Start audio spectrum monitoring via [startAudioSpectrumMonitor]. Monitoring remote played audio spectrum by callback [onRemoteAudioSpectrumUpdate]

Available since: 1.1.0

onRemoteAudioSpectrumUpdate:

- (void)onRemoteAudioSpectrumUpdate:(NSDictionary<NSString *, NSArray<NSNumber *> *> *) audioSpectrums;

The remote playing streams audio spectrum callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
audioSpectrums	NSDictionary<NSString , NSArray<NSNumber > >	Remote audio spectrum hash map, key is the streamID, value is the audio spectrum list of the corresponding streamID. Spectrum value range is [0-2^30]

Details

The remote playing streams audio spectrum callback.

Trigger: After you start the audio spectrum monitor by calling [startAudioSpectrumMonitor], you are in the state of playing the stream [startPlayingStream].
Caution: The callback notification period is the parameter value set when the [startAudioSpectrumMonitor] is called.
Related APIs: Start audio spectrum monitoring via [startAudioSpectrumMonitor]. Monitoring local played audio spectrum by callback [onCapturedAudioSpectrumUpdate].

Available since: 1.1.0

onLocalDeviceExceptionOccurred:deviceType:deviceID:

- (void)onLocalDeviceExceptionOccurred:(ZegoDeviceExceptionType) exceptionType deviceType:(ZegoDeviceType) deviceType deviceID:(NSString *) deviceID;

The callback triggered when a local device exception occurred.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
exceptionType	ZegoDeviceExceptionType	The type of the device exception.
deviceType	ZegoDeviceType	The type of device where the exception occurred.
deviceID	NSString *	Device ID. Currently, only desktop devices are supported to distinguish different devices; for mobile devices, this parameter will return an empty string.

Details

The callback triggered when a local device exception occurs.

Trigger: This callback is triggered when the function of the local audio or video device is abnormal.

Available since: 2.15.0

onRemoteCameraStateUpdate:streamID:

- (void)onRemoteCameraStateUpdate:(ZegoRemoteDeviceState) state streamID:(NSString *) streamID;

The callback triggered when the state of the remote camera changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoRemoteDeviceState	Remote camera status.
streamID	NSString *	Stream ID.

Details

The callback triggered when the state of the remote camera changes.

Use cases: Developers of 1v1 education scenarios or education small class scenarios and similar scenarios can use this callback notification to determine whether the camera device of the remote publishing stream device is working normally, and preliminary understand the cause of the device problem according to the corresponding state.
Trigger: When the state of the remote camera device changes, such as switching the camera, by monitoring this callback, it is possible to obtain an event related to the far-end camera, which can be used to prompt the user that the video may be abnormal.
Caution: This callback will not be called back when the remote stream is play from the CDN, or when custom video acquisition is used at the peer.

Available since: 1.1.0

onRemoteMicStateUpdate:streamID:

- (void)onRemoteMicStateUpdate:(ZegoRemoteDeviceState) state streamID:(NSString *) streamID;

The callback triggered when the state of the remote microphone changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoRemoteDeviceState	Remote microphone status.
streamID	NSString *	Stream ID.

Details

The callback triggered when the state of the remote microphone changes.

Use cases: Developers of 1v1 education scenarios or education small class scenarios and similar scenarios can use this callback notification to determine whether the microphone device of the remote publishing stream device is working normally, and preliminary understand the cause of the device problem according to the corresponding state.
Trigger: When the state of the remote microphone device is changed, such as switching a microphone, etc., by listening to the callback, it is possible to obtain an event related to the remote microphone, which can be used to prompt the user that the audio may be abnormal.
Caution: This callback will not be called back when the remote stream is play from the CDN, or when custom audio acquisition is used at the peer (But the stream is not published to the ZEGO RTC server.).

Available since: 1.1.0

onRemoteSpeakerStateUpdate:streamID:

- (void)onRemoteSpeakerStateUpdate:(ZegoRemoteDeviceState) state streamID:(NSString *) streamID;

The callback triggered when the state of the remote speaker changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
state	ZegoRemoteDeviceState	Remote speaker status.
streamID	NSString *	Stream ID.

Details

The callback triggered when the state of the remote microphone changes.

Use cases: Developers of 1v1 education scenarios or education small class scenarios and similar scenarios can use this callback notification to determine whether the speaker device of the remote publishing stream device is working normally, and preliminary understand the cause of the device problem according to the corresponding state.
Trigger: When the state of the remote speaker device changes, such as switching the speaker, by monitoring this callback, you can get events related to the remote speaker.
Caution: This callback will not be called back when the remote stream is play from the CDN.

Available since: 1.1.0

onAudioRouteChange:

- (void)onAudioRouteChange:(ZegoAudioRoute) audioRoute;

Callback for device's audio route changed.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
audioRoute	ZegoAudioRoute	Current audio route.

Details

Callback for device's audio route changed.

Trigger: This callback will be called when there are changes in audio routing such as earphone plugging, speaker and receiver switching, etc.
Platform differences: Only supports iOS and Android.

Available since: 1.20.0

onAudioVADStateUpdate:monitorType

- (void)onAudioVADStateUpdate:(ZegoAudioVADType)state monitorType:(ZegoAudioVADStableStateMonitorType)type;

Callback for audio VAD stable state update.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
type	ZegoAudioVADStableStateMonitorType	audio VAD monitor type
state	ZegoAudioVADType	VAD result

Details

Callback for audio VAD stable state update. When to trigger: the [startAudioVADStableStateMonitor] function must be called to start the audio VAD monitor and you must be in a state where it is publishing the audio and video stream or be in [startPreview] state.

Related APIs: [startAudioVADStableStateMonitor], [stopAudioVADStableStateMonitor].

Available since: 2.14.0
Restrictions: The callback notification period is 3 seconds.

onRecvRoomTransparentMessage:roomID:

- (void)onRecvRoomTransparentMessage:(ZegoRoomRecvTransparentMessage*) message roomID:(NSString *) roomID;

The callback triggered when Barrage Messages are received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
message	ZegoRoomRecvTransparentMessage*	recv message.
roomID	NSString *	Room ID. Value range: The maximum length is 128 bytes.

Details

This callback is used to receive room passthrough messages sent by other users in the same room. When to trigger: After calling [loginRoom] to login to the room, this callback is triggered if there is a user in the room who sends a message received by the specified client through the [sendTransparentMessage] function.

Caution: Barrage messages sent by users themselves will not be notified through this callback. When there are a large number of barrage messages in the room, the notification may be delayed, and some barrage messages may be lost.
Related callbacks: A bullet-screen message sent by the user himself is not notified by this callback. [sendTransparentMessage] specifies that only a server callback is used. This callback is not triggered.

Available since: 1.5.0
Restrictions: None

onIMRecvBroadcastMessage:roomID:

- (void)onIMRecvBroadcastMessage:(NSArray<ZegoBroadcastMessageInfo *> *) messageList roomID:(NSString *) roomID;

The callback triggered when Broadcast Messages are received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
messageList	NSArray<ZegoBroadcastMessageInfo >	List of received messages. Value range: Up to 50 messages can be received each time.
roomID	NSString *	Room ID. Value range: The maximum length is 128 bytes.

Details

This callback is used to receive broadcast messages sent by other users in the same room.

Use cases: Generally used in the live room. When to trigger: After calling [loginRoom] to log in to the room, if a user in the room sends a broadcast message via [sendBroadcastMessage] function, this callback will be triggered.
Caution: The broadcast message sent by the user will not be notified through this callback.
Related callbacks: You can receive room barrage messages through [onIMRecvBarrageMessage], and you can receive room custom signaling through [onIMRecvCustomCommand].

Available since: 1.2.1
Restrictions: None

onIMRecvBarrageMessage:roomID:

- (void)onIMRecvBarrageMessage:(NSArray<ZegoBarrageMessageInfo *> *) messageList roomID:(NSString *) roomID;

The callback triggered when Barrage Messages are received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
messageList	NSArray<ZegoBarrageMessageInfo >	List of received messages. Value range: Up to 50 messages can be received each time.
roomID	NSString *	Room ID. Value range: The maximum length is 128 bytes.

Details

This callback is used to receive barrage messages sent by other users in the same room.

Use cases: Generally used in scenarios where there is a large number of messages sent and received in the room and the reliability of the messages is not required, such as live barrage. When to trigger: After calling [loginRoom] to log in to the room, if a user in the room sends a barrage message through the [sendBarrageMessage] function, this callback will be triggered.
Caution: Barrage messages sent by users themselves will not be notified through this callback. When there are a large number of barrage messages in the room, the notification may be delayed, and some barrage messages may be lost.
Related callbacks: Develop can receive room broadcast messages through [onIMRecvBroadcastMessage], and can receive room custom signaling through [onIMRecvCustomCommand].

Available since: 1.5.0
Restrictions: None

onIMRecvCustomCommand:fromUser:roomID:

- (void)onIMRecvCustomCommand:(NSString *) command fromUser:(ZegoUser *) fromUser roomID:(NSString *) roomID;

The callback triggered when a Custom Command is received.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
command	NSString *	Command content received.Value range: The maximum length is 1024 bytes.
fromUser	ZegoUser *	Sender of the command.
roomID	NSString *	Room ID. Value range: The maximum length is 128 bytes.

Details

This callback is used to receive custom command sent by other users in the same room.

Use cases: Generally used in the live room. When to trigger: After calling [loginRoom] to log in to the room, if other users in the room send custom signaling to the developer through the [sendCustomCommand] function, this callback will be triggered.
Caution: The custom command sent by the user himself will not be notified through this callback.
Related callbacks: You can receive room broadcast messages through [onIMRecvBroadcastMessage], and you can receive room barrage message through [onIMRecvBarrageMessage].

Available since: 1.2.1
Restrictions: None

onPerformanceStatusUpdate:

- (void)onPerformanceStatusUpdate:(ZegoPerformanceStatus *) status;

System performance monitoring callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
status	ZegoPerformanceStatus *	System performance monitoring status.

Details

System performance monitoring callback. The callback notification period is the value of millisecond parameter set by call [startPerformanceMonitor].

Use cases: Monitor system performance can help user quickly locate and solve performance problems and improve user experience. When to trigger: It will triggered after [createEngine], and call [startPerformanceMonitor] to start system performance monitoring.

Available since: 1.19.0
Restrictions: None.

onNetworkModeChanged:

- (void)onNetworkModeChanged:(ZegoNetworkMode) mode;

Network mode changed callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mode	ZegoNetworkMode	Current network mode.

Details

Network mode changed callback. When to trigger: This callback will be triggered when the device's network mode changed, such as switched from WiFi to 5G, or when network is disconnected.

Available since: 1.20.0
Restrictions: None.

onNetworkSpeedTestError:type:

- (void)onNetworkSpeedTestError:(int) errorCode type:(ZegoNetworkSpeedTestType) type;

Network speed test error callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Network speed test error code. Please refer to error codes document https://docs.zegocloud.com/en/5548.html for details.
type	ZegoNetworkSpeedTestType	Uplink or downlink.

Details

Network speed test error callback.

Use cases: This function can be used to detect whether the network environment is suitable for pushing/pulling streams with specified bitrates. When to
Trigger: If an error occurs during the speed test, such as: can not connect to speed test server, this callback will be triggered.

Available since: 1.20.0
Restrictions: None.

onNetworkSpeedTestQualityUpdate:type:

- (void)onNetworkSpeedTestQualityUpdate:(ZegoNetworkSpeedTestQuality *) quality type:(ZegoNetworkSpeedTestType) type;

Network speed test quality callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
quality	ZegoNetworkSpeedTestQuality *	Network speed test quality.
type	ZegoNetworkSpeedTestType	Uplink or downlink.

Details

Network speed test quality callback when the network can be connected.

Use cases: This function can be used to detect whether the network environment is suitable for pushing/pulling streams with specified bitrates. When to
Trigger: After call [startNetworkSpeedTest] start network speed test, this callback will be triggered. The trigger period is determined by the parameter value specified by call [startNetworkSpeedTest], default value is 3 seconds
Caution: When error occurred during network speed test or [stopNetworkSpeedTest] called, this callback will not be triggered.

Available since: 1.20.0
Restrictions: None.

onNetworkQuality:upstreamQuality:downstreamQuality:

- (void)onNetworkQuality:(NSString *) userID upstreamQuality:(ZegoStreamQualityLevel) upstreamQuality downstreamQuality:(ZegoStreamQualityLevel) downstreamQuality;

The network quality callback of users who are publishing in the room.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
userID	NSString *	User ID, empty means local user
upstreamQuality	ZegoStreamQualityLevel	Upstream network quality
downstreamQuality	ZegoStreamQualityLevel	Downstream network quality

Details

The uplink and downlink network callbacks of the local and remote users, that would be called by default every two seconds for the local and each playing remote user's network quality. Versions 2.10.0 to 2.13.1:

Developer must both publish and play streams before you receive your own network quality callback.
When playing a stream, the publish end has a play stream and the publish end is in the room where it is located, then the user's network quality will be received. Versions 2.14.0 to 2.21.1:
As long as you publish or play a stream, you will receive your own network quality callback.
When you play a stream, the publish end is in the room where you are, and you will receive the user's network quality. Version 2.22.0 and above:
As long as you publish or play a stream, you will receive your own network quality callback.
When you play a stream, the publish end is in the room where you are, and you will receive the user's network quality.
Estimate the network conditions of the remote stream publishing user. If the remote stream publishing user loses one heartbeat, the network quality will be called back as unknown; if the remote stream publishing user's heartbeat loss reaches 3 Second, call back its network quality to die. Use case: When the developer wants to analyze the network condition on the link, or wants to know the network condition of local and remote users. When to

Trigger: After publishing a stream by called [startPublishingStream] or playing a stream by called [startPlayingStream].

Available since: 2.10.0

onRtcStats:

- (void)onRtcStats:(ZegoRtcStatsInfo *) info;

RTC network statistics callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
info	ZegoRtcStatsInfo *	statistical information.

Details

RTC network statistics callback.

Use cases: When a developer wants to analyze the local network situation. When to
Trigger: After calling [startPublishingStream] to start pushing the RTC stream, it will call back the upstream statistics. After calling [startPlayingStream] to start playing the RTC or L3 stream, it will call back the downlink statistics. The default callback period is 3 seconds.
Caution: None.

Available since: 3.20.0
Restrictions: None.

onNetworkTimeSynchronized

- (void)onNetworkTimeSynchronized;

Successful callback of network time synchronization.

Declared in ZegoExpressEventHandler.h

Available since: 2.12.0 This callback is triggered when internal network time synchronization completes after a developer calls [createEngine].

onRequestDumpData

- (void)onRequestDumpData;

Request to dump data.

Declared in ZegoExpressEventHandler.h

Trigger: When the customer reports back the problem, ZEGO expects the user to dump the data to analyze the audio / video processing problem, which will trigger this callback.

Available since: 3.10.0 When to

onRequestUploadDumpData:takePhoto:

- (void)onRequestUploadDumpData:(NSString *) dumpDir takePhoto:(BOOL) takePhoto;

Request to dump data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
dumpDir	NSString *	Dump data dir.
takePhoto	BOOL	Need to take photo when uploading dump data

Trigger: When the customer reports back the problem, ZEGO expects the user to dump the data to analyze the audio / video processing problem, which will trigger this callback.

Available since: 3.11.0 When to

onStartDumpData:

- (void)onStartDumpData:(int) errorCode;

Callback when starting to dump data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code.

Trigger: This callback is triggered when [startDumpData] is called.

Available since: 3.10.0 When to

onStopDumpData:dumpDir:

- (void)onStopDumpData:(int) errorCode dumpDir:(NSString *) dumpDir;

Callback when stopping to dump data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code.
dumpDir	NSString *	Dump data dir.

Trigger: This callback is triggered when [stopDumpData] is called.

Available since: 3.10.0 When to

onUploadDumpData:

- (void)onUploadDumpData:(int) errorCode;

Callback after uploading the dump data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
errorCode	int	Error code.

Trigger: When [uploadDumpData] is called, this callback will be triggered after SDK executes the upload task.

Available since: 3.10.0 When to

onMobileScreenCaptureExceptionOccurred:

- (void)onMobileScreenCaptureExceptionOccurred:(ZegoScreenCaptureExceptionType)exceptionType API_AVAILABLE(ios (12.0));

The callback triggered when a screen capture source exception occurred.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
exceptionType	ZegoScreenCaptureExceptionType	Screen capture exception type.

Details

The callback triggered when the mobile screen capture source exception occurred.

Trigger: This callback is triggered when an exception occurs after the mobile screen capture started.
Caution: The callback does not actually take effect until call [setEventHandler] to set.

Available since: 3.6.0
Restrictions: Only available on Android and iOS.

onMobileScreenCaptureStart

- (void)onMobileScreenCaptureStart API_AVAILABLE(ios (12.0));

The callback triggered when start screen capture.

Declared in ZegoExpressEventHandler.h

The callback triggered when calling the start mobile screen capture.

Trigger: After calling [startScreenCapture], this callback will be triggered when starting screen capture successfully, and [onScreenCaptureExceptionOccurred] will be triggered when failing.
Caution: The callback does not actually take effect until call [setEventHandler] to set.

Available since: 3.16.0
Restrictions: Only available on Android and iOS.

ZegoMediaPlayerAudioHandler

Declared in ZegoExpressEventHandler.h

Methods

mediaPlayer:audioFrameData:dataLength:param

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer audioFrameData:(unsigned char *)data dataLength:(unsigned int)dataLength param:(ZegoAudioFrameParam *)param;

The callback triggered when the media player throws out audio frame data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
data	unsigned char *	Raw data of audio frames.
dataLength	unsigned int	Data length.
param	ZegoAudioFrameParam *	audio frame flip mode.

Details

The callback triggered when the media player throws out audio frame data.

Trigger: The callback is generated when the media player starts playing.
Caution: The callback does not actually take effect until call [setAudioHandler] to set.

Available since: 1.3.4
Restrictions: When playing copyrighted music, this callback will be disabled by default. If necessary, please contact ZEGO technical support.

ZegoMediaPlayerEventHandler

Declared in ZegoExpressEventHandler.h

Methods

mediaPlayer:stateUpdate:errorCode

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer stateUpdate:(ZegoMediaPlayerState)state errorCode:(int)errorCode;

MediaPlayer playback status callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
state	ZegoMediaPlayerState	Media player status.
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.

Details

MediaPlayer playback status callback.

Trigger: The callback triggered when the state of the media player changes.

Available since: 1.3.4
Restrictions: None.

mediaPlayer:networkEvent

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer networkEvent:(ZegoMediaPlayerNetworkEvent)networkEvent;

The callback triggered when the network status of the media player changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
networkEvent	ZegoMediaPlayerNetworkEvent	Network status event.

Details

The callback triggered when the network status of the media player changes.

Trigger: When the media player is playing network resources, this callback will be triggered when the status change of the cached data.
Related APIs: [setNetWorkBufferThreshold].

Available since: 1.3.4
Restrictions: The callback will only be triggered when the network resource is played.

mediaPlayer:playingProgress

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer playingProgress:(unsigned long long)millisecond;

The callback to report the current playback progress of the media player.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
millisecond	unsigned long long	Progress in milliseconds.

Details

The callback triggered when the network status of the media player changes. Set the callback interval by calling [setProgressInterval]. When the callback interval is set to 0, the callback is stopped. The default callback interval is 1 second.

Trigger: When the media player is playing network resources, this callback will be triggered when the status change of the cached data.
Related APIs: [setProgressInterval].

Available since: 1.3.4
Restrictions: None.

mediaPlayer:renderingProgress

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer renderingProgress:(unsigned long long)millisecond;

The callback to report the current rendering progress of the media player.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
millisecond	unsigned long long	Progress in milliseconds.

Details

The callback to report the current rendering progress of the media player. Set the callback interval by calling [setProgressInterval]. When the callback interval is set to 0, the callback is stopped. The default callback interval is 1 second.

Trigger: This callback will be triggered when the media player starts playing resources.
Related APIs: [setProgressInterval].

Available since: 3.8.0
Restrictions: None.

mediaPlayer:videoSizeChanged

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer videoSizeChanged:(CGSize)size;

The callback triggered when when the resolution of the playback video changes.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
size	CGSize	Resolution.

Details

The callback triggered when when the resolution of the playback video changes.

Trigger: When the media player is playing a video resource, This callback will be triggered when playback starts and the resolution of the video changes.

Available since: 3.11.0

mediaPlayer:recvSEI

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer recvSEI:(NSData *)data;

The callback triggered when the media player got media side info.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
data		SEI content.

Details

The callback triggered when the media player got media side info.

Trigger: When the media player starts playing media files, the callback is triggered if the SEI is resolved to the media file.
Caution: The callback does not actually take effect until call [setEventHandler] to set.

Available since: 2.2.0

mediaPlayer:soundLevelUpdate

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer soundLevelUpdate:(float)soundLevel;

The callback of sound level update.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
soundLevel	float	Sound level value, value range: [0.0, 100.0] (This value only represents the range of the sound level value returned by the callback, not the precision.).

Details

The callback of sound level update.

Trigger: The callback frequency is specified by [EnableSoundLevelMonitor].
Caution: The callback does not actually take effect until call [setEventHandler] to set.
Related APIs: To monitor this callback, you need to enable it through [EnableSoundLevelMonitor].

Available since: 2.15.0

mediaPlayer:frequencySpectrumUpdate

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer frequencySpectrumUpdate:(NSArray<NSNumber *> *)spectrumList;

The callback of frequency spectrum update.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
spectrumList	NSArray<NSNumber >	Locally captured frequency spectrum value list. Spectrum value range is [0-2^30].

Details

The callback of frequency spectrum update.

Trigger: The callback frequency is specified by [EnableFrequencySpectrumMonitor].
Caution: The callback does not actually take effect until call [setEventHandler] to set.
Related APIs: To monitor this callback, you need to enable it through [EnableFrequencySpectrumMonitor].

Available since: 2.15.0

mediaPlayer:firstFrameEvent

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer firstFrameEvent:(ZegoMediaPlayerFirstFrameEvent)event;

The callback triggered when the media player plays the first frame.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
event	ZegoMediaPlayerFirstFrameEvent	The first frame callback event type.

Details

The callback triggered when the media player plays the first frame.

Trigger: This callback is generated when the media player starts playing.
Caution: The callback does not actually take effect until call [setEventHandler] to set.
Related APIs: You need to call the [setPlayerCanvas] interface to set the view for the media player in order to receive the video first frame event callback.

Available since: 3.5.0

mediaPlayer:localCacheError:resource:cachedFile

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer localCacheError:(int)errorCode resource:(NSString *)resource cachedFile:(NSString *)cachedFile;

The callback triggered when the media player caches http/https network resource locally.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
errorCode	int	Error code.
resource	NSString *	Played resource
cachedFile	NSString *	Cached file

Details

The callback triggered when the media player caches http/https network resource locally.

Trigger: This callback occurs after the media player caches http/https network resources.
Caution: This callback will not take effect until the [enableLocalCache] API is called and the http/https network resources are played.
Related APIs: Need to call the [enableLocalCache] interface.

Available since: 3.12.0

ZegoMediaPlayerVideoHandler

Declared in ZegoExpressEventHandler.h

Methods

mediaPlayer:videoFrameRawData:dataLength:param

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer videoFrameRawData:(const unsigned char * _Nonnull * _Nonnull)data dataLength:(unsigned int *)dataLength param:(ZegoVideoFrameParam *)param;

The callback triggered when the media player throws out video frame data.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
data	const unsigned char * _Nonnull * _Nonnull	Raw data of video frames (eg: RGBA only needs to consider data[0], I420 needs to consider data[0,1,2]).
dataLength	unsigned int *	Data length (eg: RGBA only needs to consider dataLength[0], I420 needs to consider dataLength[0,1,2]).
param	ZegoVideoFrameParam *	Video frame flip mode.

Details

The callback triggered when the media player throws out video frame data.

Trigger: The callback is generated when the media player starts playing.
Caution: The callback does not actually take effect until call [setVideoHandler] to set.

Available since: 1.3.4
Restrictions: When playing copyrighted music, this callback will be disabled by default. If necessary, please contact ZEGO technical support.

mediaPlayer:videoFrameRawData:dataLength:param:extraInfo

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer videoFrameRawData:(const unsigned char * _Nonnull * _Nonnull)data dataLength:(unsigned int *)dataLength param:(ZegoVideoFrameParam *)param extraInfo:(NSDictionary *)extraInfo;

The callback triggered when the media player throws out video frame data, with additional information for the video frame.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object.
data	const unsigned char * _Nonnull * _Nonnull	Raw data of video frames (eg: RGBA only needs to consider data[0], I420 needs to consider data[0,1,2]).
dataLength	unsigned int *	Data length (eg: RGBA only needs to consider dataLength[0], I420 needs to consider dataLength[0,1,2]).
param	ZegoVideoFrameParam *	Video frame flip mode.
extraInfo	nullable NSDictionary *	Video frame extra info.

Details

The callback triggered when the media player throws out video frame data.

Trigger: The callback is generated when the media player starts playing.
Caution: The callback does not actually take effect until call [setVideoHandler] to set.

Available since: 2.16.0
Restrictions: When playing copyrighted music, this callback will be disabled by default. If necessary, please contact ZEGO technical support.

mediaPlayer:videoFramePixelBuffer:param

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer videoFramePixelBuffer:(CVPixelBufferRef)buffer param:(ZegoVideoFrameParam *)param;

The callback triggered when the media player throws out video frame data (in CVPixelBuffer format).

Declared in ZegoExpressEventHandler.h

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object
buffer	CVPixelBufferRef	video data of CVPixelBuffer format
param	ZegoVideoFrameParam *	video data frame param

mediaPlayer:videoFramePixelBuffer:param:extraInfo

- (void)mediaPlayer:(ZegoMediaPlayer *)mediaPlayer videoFramePixelBuffer:(CVPixelBufferRef)buffer param:(ZegoVideoFrameParam *)param extraInfo:(NSDictionary *)extraInfo;

The callback triggered when the media player throws out video frame data (in CVPixelBuffer format).

Declared in ZegoExpressEventHandler.h

Name	Type	Description
mediaPlayer	ZegoMediaPlayer *	Callback player object
buffer	CVPixelBufferRef	video data of CVPixelBuffer format
param	ZegoVideoFrameParam *	video data frame param
extraInfo	nullable NSDictionary *	video data frame extra info.

ZegoRangeAudioEventHandler

Declared in ZegoExpressEventHandler.h

Methods

rangeAudio:microphoneStateUpdate:errorCode

- (void)rangeAudio:(ZegoRangeAudio *)rangeAudio microphoneStateUpdate:(ZegoRangeAudioMicrophoneState)state errorCode:(int)errorCode;

Range audio microphone state callback.

Declared in ZegoExpressEventHandler.h

Parameters

Name	Type	Description
rangeAudio	ZegoRangeAudio *	Range audio instance that triggers this callback.
state	ZegoRangeAudioMicrophoneState	The use state of the range audio.
errorCode	int	Error code, please refer to the error codes document https://docs.zegocloud.com/en/5548.html for details.

Details

The status change notification of the microphone, starting to send audio is an asynchronous process, and the state switching in the middle is called back through this function. When to

Trigger: After the [enableMicrophone] function.
Caution: 1. It must be monitored before the [enableMicrophone] function is called. 2. The callback is not triggered when the [enableMicrophone] is stopped normally, and the Off state is triggered only when the [enableMicrophone] is stopped abnormally.

Available since: 2.11.0