Pre-call Detection

Function Overview

To ensure a real-time call experience, devices can be detected before the call to identify and troubleshoot problems in advance.

Device detection mainly detects whether the local microphone, camera, and speaker can work normally.

This article will introduce how to use ZEGO SDK interfaces to implement device detection.

Prerequisites

Before implementing pre-call device detection functionality, please ensure:

• You have created a project in ZEGOCLOUD Console and applied for valid AppID and AppSign. For details, please refer to Console - Project Information.
• You have integrated ZEGO Express SDK in the project and implemented basic audio and video streaming functions. For details, please refer to Quick Start - Integration and Quick Start - Implementation.

Device Detection

Microphone Detection

Detection Logic

The microphone device detection flow is shown in the following figure:

Corresponding Interfaces

1. Start Microphone

Call the StartPreview interface to start audio capture without publishing stream.

engine.StartPreview();

engine.StartPreview();

2. Detect Microphone Permission

ZEGO SDK will automatically check microphone permissions. If the user has not authorized, it will request user consent; if the user refuses, the user needs to manually enable permissions in system settings.

3. Detect Whether Microphone is Available

Detect whether the device is abnormal through the following callback. If no abnormal feedback is detected (you can synchronously start "4. Detect Microphone Audio Data"), and the microphone audio data detection is normal, then the microphone device is available.

• Version 2.15.0 and later: Listen to the OnLocalDeviceExceptionOccurred callback to detect whether the device is abnormal.
• Versions before 2.15.0: Listen to the OnDeviceError callback to detect whether the device is abnormal.

/**
 * Local device exception notification.
 *
 * Supported versions: 2.15.0 and later.
 * Description: Local device exception.
 * Trigger timing: This callback is triggered when local audio or video device function is abnormal.
 *
 * @param exceptionType Device exception type.
 * @param deviceType Device type that is abnormal.
 * @param deviceID Device ID. Currently only supports desktop devices, used to identify specific devices; for mobile devices, this parameter will return an empty string.
 */
public delegate void OnLocalDeviceExceptionOccurred(ZegoDeviceExceptionType exceptionType,ZegoDeviceType deviceType,string deviceID);

/**
 * Local device exception notification.
 *
 * Supported versions: 2.15.0 and later.
 * Description: Local device exception.
 * Trigger timing: This callback is triggered when local audio or video device function is abnormal.
 *
 * @param exceptionType Device exception type.
 * @param deviceType Device type that is abnormal.
 * @param deviceID Device ID. Currently only supports desktop devices, used to identify specific devices; for mobile devices, this parameter will return an empty string.
 */
public delegate void OnLocalDeviceExceptionOccurred(ZegoDeviceExceptionType exceptionType,ZegoDeviceType deviceType,string deviceID);

4. Detect Microphone Audio Data

Call the StartSoundLevelMonitor interface to get the energy value of the sound collected by the microphone. If the data is normal, the microphone is working properly and can be used for calls.

engine.StartSoundLevelMonitor();

engine.StartSoundLevelMonitor();

Camera Detection

Detection Logic

The camera device detection flow is shown in the following figure:

Corresponding Interfaces

1. Start Camera

Call the StartPreview interface to bind the view of the camera preview (for details, please refer to Enable Local Preview), and start video capture and preview without publishing stream.

engine.StartPreview();

engine.StartPreview();

2. Detect Camera Permission

ZEGO SDK will automatically check camera permissions. If the user has not authorized, it will request user consent; if the user refuses, the user needs to manually enable permissions in system settings.

3. Detect Whether Camera is Available

Detect whether the device is abnormal through the following callback. If no abnormal feedback is detected (you can synchronously start "4. Detect Whether Video is Normal"), and the video display is normal, then the device is available.

• Version 2.15.0 and later: Listen to the OnLocalDeviceExceptionOccurred callback to detect whether the device is abnormal.
• Versions before 2.15.0: Listen to the OnDeviceError callback to detect whether the device is abnormal.

/**
 * Local device exception notification.
 *
 * Supported versions: 2.15.0 and later.
 * Description: Local device exception.
 * Trigger timing: This callback is triggered when local audio or video device function is abnormal.
 *
 * @param exceptionType Device exception type.
 * @param deviceType Device type that is abnormal.
 * @param deviceID Device ID. Currently only supports desktop devices, used to identify specific devices; for mobile devices, this parameter will return an empty string.
 */
public delegate void OnLocalDeviceExceptionOccurred(ZegoDeviceExceptionType exceptionType,ZegoDeviceType deviceType,string deviceID);

/**
 * Local device exception notification.
 *
 * Supported versions: 2.15.0 and later.
 * Description: Local device exception.
 * Trigger timing: This callback is triggered when local audio or video device function is abnormal.
 *
 * @param exceptionType Device exception type.
 * @param deviceType Device type that is abnormal.
 * @param deviceID Device ID. Currently only supports desktop devices, used to identify specific devices; for mobile devices, this parameter will return an empty string.
 */
public delegate void OnLocalDeviceExceptionOccurred(ZegoDeviceExceptionType exceptionType,ZegoDeviceType deviceType,string deviceID);

4. Detect Whether Video is Normal

If the video display is normal at this time, the camera is working properly and can be used for calls.

Speaker Detection

Detection Logic

The playback device detection flow is shown in the following figure:

Corresponding Interfaces

1. Use Audio Effect Player to Play Audio File

Call the ZegoAudioEffectPlayer interface to play your audio file used for testing.

// 1. Create audio effect player
ZegoAudioEffectPlayer audioEffectPlayer= engine.CreateAudioEffectPlayer();
// 2. Load resource
string currentSelectPath = "xxx";
audioEffectPlayer.LoadResource(1, currentSelectPath, (errorCode) =>
{
    Debug.Log("LoadResource errorCode:" + errorCode);
});
// 3. Play resource
audioEffectPlayer.Start(1, currentSelectPath, null);

// 1. Create audio effect player
ZegoAudioEffectPlayer audioEffectPlayer= engine.CreateAudioEffectPlayer();
// 2. Load resource
string currentSelectPath = "xxx";
audioEffectPlayer.LoadResource(1, currentSelectPath, (errorCode) =>
{
    Debug.Log("LoadResource errorCode:" + errorCode);
});
// 3. Play resource
audioEffectPlayer.Start(1, currentSelectPath, null);

2. Detect Whether Sound is Heard

If you can hear the corresponding audio, the playback device is working properly and can be used for calls. Call the OnAudioEffectPlayStateUpdate callback to view the audio effect player status:

/**
 * Audio effect playback state callback.
 *
 * Supported versions: 1.16.0 and later.
 * Description: This callback is triggered when the playback state of an audio effect in the audio effect player changes.
 * Trigger timing: This callback is triggered when the playback state of an audio effect changes.
 * Usage restrictions: None.
 *
 * @param audioEffectPlayer The audio effect player instance that triggered this callback.
 * @param audioEffectID The ID of the audio effect resource that triggered this callback.
 * @param state The playback state of the audio effect.
 * @param errorCode Error code, for details please refer to common error code document https://www.zegocloud.com/docs/real-time-video-android-java/client-sdk/error-code.html .
 */
public delegate void OnAudioEffectPlayStateUpdate(ZegoAudioEffectPlayer audioEffectPlayer, uint audioEffectID, ZegoAudioEffectPlayState state, int errorCode);

/**
 * Audio effect playback state callback.
 *
 * Supported versions: 1.16.0 and later.
 * Description: This callback is triggered when the playback state of an audio effect in the audio effect player changes.
 * Trigger timing: This callback is triggered when the playback state of an audio effect changes.
 * Usage restrictions: None.
 *
 * @param audioEffectPlayer The audio effect player instance that triggered this callback.
 * @param audioEffectID The ID of the audio effect resource that triggered this callback.
 * @param state The playback state of the audio effect.
 * @param errorCode Error code, for details please refer to common error code document https://www.zegocloud.com/docs/real-time-video-android-java/client-sdk/error-code.html .
 */
public delegate void OnAudioEffectPlayStateUpdate(ZegoAudioEffectPlayer audioEffectPlayer, uint audioEffectID, ZegoAudioEffectPlayState state, int errorCode);