Get the Raw Audio Data
Feature Overview
The SDK provides developers with the function of obtaining raw audio data. The format of the obtained raw audio data is PCM. Developers can write this data to local devices to implement audio recording.
Usage Steps
The usage flow for Get the Raw Audio Data is as follows.
1 Initialize SDK
Please refer to "Create Engine" in Quick Start - Implementation Flow.
2 Enable Raw Audio Data Function
Developers can call the startAudioDataObserver interface to enable audio data callback monitoring. The audio data type of the callback is ZegoAudioDataCallbackBitMask, including ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_CAPTURED, ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_PLAYBACK, ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_MIXED, ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_PLAYER. All four callback types need to be enabled.
// Enable Get the Raw Audio Data function
ZegoAudioFrameParam param;
param.channel = ZEGO_AUDIO_CHANNEL_STEREO;
param.sampleRate = ZEGO_AUDIO_SAMPLE_RATE_8K;
unsigned int bitmask = ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_CAPTURED | ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_PLAYBACK | ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_MIXED | ZEGO_AUDIO_DATA_CALLBACK_BIT_MASK_PLAYER;
engine->startAudioDataObserver(bitmask, param);If needed, please contact ZEGOCLOUD Technical Support.
3 Set Callback to Receive Raw Audio Data and Process
Developers can call the setAudioDataHandler interface to set an additional callback for receiving audio data. According to needs, implement callbacks onCapturedAudioData, onPlaybackAudioData, onMixedAudioData, onPlayerAudioData, corresponding to the four audio data types in ZegoAudioDataCallbackBitMask above.
// Set raw audio data callback
// Please note, do not call any SDK interfaces in the SDK callback thread, you need to manually switch to another thread, otherwise a deadlock will occur
class MyAudioDataHandler: public IZegoAudioDataHandler
{
public:
// Local captured audio data, callback can be received after publishing stream
virtual void onCapturedAudioData(const unsigned char* /*data*/, unsigned int /*dataLength*/, ZegoAudioFrameParam /*param*/) {
}
// Remote playing stream audio data, callback can be received after starting playing stream
virtual void onPlaybackAudioData(const unsigned char* /*data*/, unsigned int /*dataLength*/, ZegoAudioFrameParam /*param*/) {
}
// Audio data callback after mixing local captured and remote playing stream sounds
virtual void onMixedAudioData(const unsigned char* /*data*/, unsigned int /*dataLength*/, ZegoAudioFrameParam /*param*/) {
}
// Remote playing stream audio data, callback for each playing stream data after starting playing stream
virtual void onPlayerAudioData(const unsigned char* /*data*/, unsigned int /*dataLength*/, ZegoAudioFrameParam /*param*/, const std::string& /*streamID*/) {
}
};
engine->setAudioDataHandler(std::make_shared<MyAudioDataHandler>());4 Stop Audio Data Callback Monitoring
If you want to stop audio data callback monitoring, you can call the stopAudioDataObserver interface.
[[ZegoExpressEngine sharedEngine] stopAudioDataObserver];