在基于AWS KVS开发音视频建立双向直播流的过程中碰到一个问题，APP端不需要发送手机端的音视频，只需要接收设备端的音视频，但是在APP中播放远端音频（Remote Audio Track）的时候，音频一直占用通话声道，而不是音乐通道，那如何解决这个问题？
有二种方式，第一种方式是修改源码，第二种方式则是不使用默认的JavaAudioDeviceModule自定义创建。这里主要讲第二种方式。
一、创建自定义JavaAudioDeviceModule
主要是修改audioAttributes, 代码如下：
import android.content.Context
import android.media.*
import android.util.Log
import org.webrtc.audio.JavaAudioDeviceModule
/**
* @description 用于将 WebRTC 的音频输出切换到媒体声道（STREAM_MUSIC）,而不是默认的通话声道（STREAM_VOICE_CALL）
*/
class MediaAudioManager(private val context: Context) {
/**
* 创建 JavaAudioDeviceModule，并强制使用媒体通道输出
*/
fun createJavaAudioDeviceModule(): JavaAudioDeviceModule {
val audioAttributes = AudioAttributes.Builder()
.setUsage(AudioAttributes.USAGE_MEDIA)
.setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
.build()
val audioRecordErrorCallback = object : JavaAudioDeviceModule.AudioRecordErrorCallback {
override fun onWebRtcAudioRecordInitError(errorMessage: String?) {
Log.e("MediaAudioManager", "onWebRtcAudioRecordInitError: $errorMessage")
}
override fun onWebRtcAudioRecordStartError(
errorCode: JavaAudioDeviceModule.AudioRecordStartErrorCode?,
errorMessage: String?
) {
Log.e("MediaAudioManager", "onWebRtcAudioRecordStartError: $errorMessage")
}
override fun onWebRtcAudioRecordError(errorMessage: String?) {
Log.e("MediaAudioManager", "onWebRtcAudioRecordError: $errorMessage")
}
}
val audioTrackErrorCallback = object : JavaAudioDeviceModule.AudioTrackErrorCallback {
override fun onWebRtcAudioTrackInitError(errorMessage: String?) {
Log.e("MediaAudioManager", "onWebRtcAudioTrackInitError: $errorMessage")
}
override fun onWebRtcAudioTrackStartError(
errorCode: JavaAudioDeviceModule.AudioTrackStartErrorCode?,
errorMessage: String?
) {
Log.e("MediaAudioManager", "onWebRtcAudioTrackStartError: $errorMessage")
}
override fun onWebRtcAudioTrackError(errorMessage: String?) {
Log.e("MediaAudioManager", "onWebRtcAudioTrackError: $errorMessage")
}
}
// 创建 JavaAudioDeviceModule 并使用 MEDIA 声道
return JavaAudioDeviceModule.builder(context)
.setAudioAttributes(audioAttributes)
.setUseHardwareAcousticEchoCanceler(true)
.setUseHardwareNoiseSuppressor(true)
.setAudioRecordErrorCallback(audioRecordErrorCallback)
.setAudioTrackErrorCallback(audioTrackErrorCallback)
.createAudioDeviceModule()
}
}
在构建PeerConnectionFactory时使用：
PeerConnectionFactory.builder().apply {
//解决声音播放占用通话通道的问题
val mediaAudioManager = MediaAudioManager(mContext)
val audioModule = mediaAudioManager.createJavaAudioDeviceModule()
setAudioDeviceModule(audioModule)
...其他配置略...
}.createPeerConnectionFactory()
二、声音通道的控制以及占用的问题
一般情况下都会有一个按钮控制静音，静音或开启的控制逻辑需要区分用户是否佩戴耳机，佩戴耳机的情况下不能开启扬声器避免暴露隐私，具体代码如下：
/**
* 开启或关闭声音
*/
fun enableAudio(enable: Boolean) {
if (enable) {
//请求声道焦点，占用声道
requestAudioFocus()
audioManager?.mode = AudioManager.MODE_NORMAL
//判断是否佩戴耳机来开启或关闭扬声器
setSpeakerphoneOn(!isHeadphonesPlugged())
} else {
//释放声道焦点
abandonAudioFocus()
originalAudioMode?.let { audioManager?.mode = it }
originalSpeakerphoneOn?.let { audioManager?.isSpeakerphoneOn = it }
}
try {
remoteAudioTrack?.setEnabled(enable)
} catch (ex: Exception) {
Log.d(TAG,"enable Audio but remote Audio Track has been disposed")
}
}
检测是否佩戴有线或蓝牙耳机：
/**
* 判断是否佩戴耳机,佩戴耳机音频不外放
*/
private fun isHeadphonesPlugged(): Boolean {
val audioDevices = audioManager?.getDevices(AudioManager.GET_DEVICES_OUTPUTS)
if (audioDevices != null) {
for (deviceInfo in audioDevices) {
if (deviceInfo.type == AudioDeviceInfo.TYPE_WIRED_HEADPHONES
|| deviceInfo.type == AudioDeviceInfo.TYPE_WIRED_HEADSET
|| deviceInfo.type == AudioDeviceInfo.TYPE_BLUETOOTH_A2DP
) {
return true
}
}
}
return false
}
打开手机扬声器的代码：
/**
* 设置扬声器的开启和关闭
*/
@SuppressLint("NewApi")
private fun setSpeakerphoneOn(enabled: Boolean) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) { //Android 12及以上
val preferredDevice = if (enabled) {
// 获取扬声器设备
val audioDevices = audioManager?.availableCommunicationDevices
audioDevices?.firstOrNull { it.type == AudioDeviceInfo.TYPE_BUILTIN_SPEAKER }
} else {
// 恢复默认设备
null
}
preferredDevice?.let {
audioManager?.setCommunicationDevice(it)
} ?: run {
audioManager?.clearCommunicationDevice()
}
} else {
// 旧版本兼容方式 (Android 11及以下)
audioManager?.mode = if (enabled) AudioManager.MODE_NORMAL else AudioManager.MODE_IN_COMMUNICATION
audioManager?.isSpeakerphoneOn = enabled
}
}
请求声道焦点并占用和释放声道占用的代码，注意断开WebRTC的地方也要释放声道占用
private var focusRequest: AudioFocusRequest? = null //声道焦点
/**
* 请求声道焦点并占用，比如用户正在播放歌曲，可以暂停播放歌曲改为播放WebRTC音频
*/
private fun requestAudioFocus() {
val focusChangeListener = AudioManager.OnAudioFocusChangeListener { focusChange ->
when (focusChange) {
AudioManager.AUDIOFOCUS_GAIN -> {
// 获得焦点，可以播放WebRTC音频
Log.d(TAG,"AUDIOFOCUS_GAIN")
}
AudioManager.AUDIOFOCUS_LOSS -> {
// 永久失去焦点，别的App接管了，比如音乐播放器恢复
Log.d(TAG,"AUDIOFOCUS_LOSS")
}
AudioManager.AUDIOFOCUS_LOSS_TRANSIENT -> {
// 临时失去焦点（短时间内别的App在播放），应暂停音频
Log.d(TAG,"AUDIOFOCUS_LOSS_TRANSIENT")
}
AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK -> {
// 可“压低音量”继续播放（不建议WebRTC使用）
Log.d(TAG,"AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK")
}
}
}
// Android 8.0+ 使用 AudioFocusRequest.Builder
focusRequest = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN_TRANSIENT)
.setOnAudioFocusChangeListener(focusChangeListener)
.setAudioAttributes(
AudioAttributes.Builder()
.setUsage(AudioAttributes.USAGE_MEDIA)
.setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
.build()
)
.build()
val result = audioManager?.requestAudioFocus(focusRequest!!)
if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
Log.d(TAG,"Audio focus granted. Other apps will pause.")
} else {
Log.d(TAG,"Audio focus request failed.")
}
}
/**
* 释放声道焦点
*/
private fun abandonAudioFocus() {
focusRequest?.let {
audioManager?.abandonAudioFocusRequest(it)
FoxxLog.d("Audio focus released.")
}
}
部分类或对象找不到需要参考AWS KVS的Demo。做这类需求的应该能看明白。
