WebRTC Android 回声消除

前言

WebRTC源代码中设计了两个回声消除模块，AEC(Acoustic Echo Canceller)和AECM(Acoustic Echo Canceller Mobile)，AEC是在电脑端使用的回声消除器，而AECM是在移动端使用。由于电脑与移动设备的差别比较明显，在处理速度上，编解码器的性能上和内存方面都有着较大的差异。

主体

AudioManager 设置为通话模式，如下:

audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);audioManager.setSpeakerphoneOn(false);

创建 PeerConnect的时候设置如下：

WebRtcAudioUtils.setWebRtcBasedAcousticEchoCanceler(true);WebRtcAudioUtils.useWebRtcBasedAcousticEchoCanceler();WebRtcAudioUtils.setWebRtcBasedAutomaticGainControl(true);WebRtcAudioUtils.useWebRtcBasedAutomaticGainControl();WebRtcAudioUtils.setWebRtcBasedNoiseSuppressor(true);WebRtcAudioUtils.useWebRtcBasedNoiseSuppressor();WebRtcAudioManager.setBlacklistDeviceForOpenSLESUsage(true);

或者进行如下设置：

audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googEchoCancellation", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googEchoCancellation2", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googDAEchoCancellation", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googTypingNoiseDetection", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googAutoGainControl", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googAutoGainControl2", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googNoiseSuppression", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googNoiseSuppression2", "true"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googAudioMirroring", "false"));audioConstraints.mandatory.add(new MediaConstraints.KeyValuePair("googHighpassFilter", "true"));

JavaAudioDeviceModule 创建时进行如下设置：

private JavaAudioDeviceModule audioDeviceModule;private JavaAudioDeviceModule.Builder audioDeviceModuleBuilder;audioDeviceModuleBuilder = JavaAudioDeviceModule.builder(ContextUtils.getApplicationContext());this.audioDeviceModule = audioDeviceModuleBuilder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER).setUseHardwareAcousticEchoCanceler(false).setUseHardwareNoiseSuppressor(false).createAudioDeviceModule();