android怎么做多音频输出

在 Android 平台上，要实现多路音频输出可以考虑以下几种方式：

1. 使用 Android 原生的 AudioManager 类提供的 setParameters() 方法，该方法可以设置音频路由和音频流，从而实现多路音频输出。例如，你可以使用以下代码将音频路由设置为外部扬声器：

AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
audioManager.setParameters("routing=2");

2. 使用 AudioTrack 或 MediaPlayer 类创建多个音频播放器实例，将不同的音频数据分别输出到不同的设备上。例如，你可以使用以下代码将不同的音频数据输出到外部扬声器和耳机上：

AudioTrack audioTrack1 = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT, 2048, AudioTrack.MODE_STREAM);
AudioTrack audioTrack2 = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT, 2048, AudioTrack.MODE_STREAM);

audioTrack1.setPreferredDevice(AudioManager.DEVICE_OUT_SPEAKER);
audioTrack2.setPreferredDevice(AudioManager.DEVICE_OUT_WIRED_HEADSET);

audioTrack1.play();
audioTrack2.play();

// 将音频数据写入不同的 AudioTrack 实例

3. 使用 OpenSL ES 库提供的多路音频输出功能。OpenSL ES 是 Android 平台上的一个音频库，提供了更底层的音频控制接口，可以实现更高级的音频功能。你可以使用以下代码创建多个音频输出通道：

SLObjectItf outputMixObject;
slCreateEngine(&engineObject, 0, 0, 0, 0, 0);
(*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
(*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);

const SLInterfaceID ids[1] = {SL_IID_VOLUME};
const SLboolean req[1] = {SL_BOOLEAN_FALSE};

(*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 1, ids, req);
(*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);

SLDataFormat_PCM format_pcm = {
    SL_DATAFORMAT_PCM, 2, SL_SAMPLINGRATE_44_1,
    SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16,
    SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, SL_BYTEORDER_LITTLEENDIAN
};

SLDataLocator_OutputMix outputMix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};
SLDataSink audioSink = {&outputMix, NULL};

SLObjectItf playerObject1, playerObject2;
SLPlayItf playerPlay1, playerPlay2;
SLBufferQueueItf playerBufferQueue1, playerBufferQueue2;

SLDataSource audioSrc1 = {&uriDataSource, &format_pcm};
SLDataSource audioSrc2 = {&uriDataSource, &format_pcm};

const SLInterfaceID ids1[2] = {SL_IID_BUFFERQUEUE, SL_IID_VOLUME};
const SLInterfaceID ids2[2] = {SL_IID_BUFFERQUEUE, SL_IID_VOLUME};
const SLboolean req1[2] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};
const SLboolean req2[2] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};

(*engineEngine)->CreateAudioPlayer(engineEngine, &playerObject1, &audioSrc1, &audioSink, 2, ids1, req1);
(*playerObject1)->Realize(playerObject1, SL_BOOLEAN_FALSE);
(*playerObject1)->GetInterface(playerObject1, SL_IID_PLAY, &playerPlay1);
(*playerObject1)->GetInterface(playerObject1, SL_IID_BUFFERQUEUE, &playerBufferQueue1);

(*engineEngine)->CreateAudioPlayer(engineEngine, &playerObject2, &audioSrc2, &audioSink, 2, ids2, req2);
(*playerObject2)->Realize(playerObject2, SL_BOOLEAN_FALSE);
(*playerObject2)->GetInterface(playerObject2, SL_IID_PLAY, &playerPlay2);
(*playerObject2)->GetInterface(playerObject2, SL_IID_BUFFERQUEUE, &playerBufferQueue2);

这些方法都可以实现多路音频输出，选择哪一种取决于你的具体需求和应用场景。