一种“在 Android 设备上，播放视频的同时，获取实时音频流”的有效方案

ssize_t AudioTrack::write(const void* buffer, size_t userSize, bool blocking) { if (mTransfer != TRANSFER_SYNC) { return INVALID_OPERATION; }
if (isDirect()) {
    AutoMutex lock(mLock);
    int32_t flags = android_atomic_and(
                        ~(CBLK_UNDERRUN | CBLK_LOOP_CYCLE | CBLK_LOOP_FINAL | CBLK_BUFFER_END),
                        &mCblk->mFlags);
    if (flags & CBLK_INVALID) {
        return DEAD_OBJECT;
    }
}

if (ssize_t(userSize) < 0 || (buffer == NULL && userSize != 0)) {
    // Sanity-check: user is most-likely passing an error code, and it would
    // make the return value ambiguous (actualSize vs error).
    ALOGE("AudioTrack::write(buffer=%p, size=%zu (%zd)", buffer, userSize, userSize);
    return BAD_VALUE;
}

size_t written = 0;
Buffer audioBuffer;

while (userSize >= mFrameSize) {
    audioBuffer.frameCount = userSize / mFrameSize;

    status_t err = obtainBuffer(&audioBuffer,
            blocking ? &ClientProxy::kForever : &ClientProxy::kNonBlocking);
    if (err < 0) {
        if (written > 0) {
            break;
        }
        if (err == TIMED_OUT || err == -EINTR) {
            err = WOULD_BLOCK;
        }
        return ssize_t(err);
    }

    size_t toWrite = audioBuffer.size;
    memcpy(audioBuffer.i8, buffer, toWrite);     

    mBuffer = malloc(toWrite);
    memcpy(mBuffer,buffer,toWrite);

    if(mCurrentPlayMusicStream && mSocketHasInit){
       onSocketSendData(toWrite);
     }


    buffer = ((const char *) buffer) + toWrite;
    userSize -= toWrite;
    written += toWrite;

    releaseBuffer(&audioBuffer);
}

if (written > 0) {
    mFramesWritten += written / mFrameSize;
}
return written;
展开 

  #define DEST_PORT 5046
#define DEST_IP_ADDRESS "192.168.7.6"

int mSocket;
bool mSocketHasInit;
bool mCurrentPlayMusicStream;
struct sockaddr_in mRemoteAddr;

   ssize_t AudioTrack::write(const void* buffer, size_t userSize, bool blocking)
{
       ......
        size_t toWrite = audioBuffer.size;
        memcpy(audioBuffer.i8, buffer, toWrite);     

        mBuffer = malloc(toWrite);
        memcpy(mBuffer,buffer,toWrite);
        //我们添加的代码：把音频流实时的发送出去
       if(mCurrentPlayMusicStream && mSocketHasInit){
           onSocketSendData(toWrite);
         }
        ......
}

int AudioTrack::onSocketSendData(uint32_t len){
       assert(NULL != mBuffer);
       assert(-1 != len);

      if(!mSocketHasInit){
          initTcpSocket();
       }

      unsigned int ret = send(mSocket, mBuffer,len, 0);   
      free(mBuffer);
      return 0;
}
展开 

 ---------- PlayActivity.java ----------------------------

    private ServerSocket mTcpServerSocket = null;
    private List<Socket> mSocketList = new ArrayList<>();
    private MyTcpListener mTcpListener = null;

    private boolean isAccept = true;
    /**
     * 设置socket监听
     */
    public void startTcpService() {
        Log.v(TAG,"startTcpService();");
        if(mTcpListener == null){
            mTcpListener = new MyTcpListener();
        }

        new Thread() {
            @Override
            public void run() {
                super.run();
                try {
                    mTcpServerSocket = new ServerSocket();
                    mTcpServerSocket.setReuseAddress(true);
                    InetSocketAddress socketAddress = new InetSocketAddress(AndroidBoxProtocol.TCP_AUDIO_STREAM_PORT);
                    mTcpServerSocket.bind(socketAddress);

                    while (isAccept) {
                        Socket socket = mTcpServerSocket.accept();
                        mSocketList.add(socket);

                        //开启新线程接收socket 数据
                        new Thread(new TcpServerThread(socket,mTcpListener)).start();
                    }
                } catch (Exception e) {
                    Log.e("TcpServer", "" + e.toString());
                }
            }
        }.start();
    }
 /**
   * 停止socket监听
  */
 private void stopTcpService(){

        isAccept = false;
        if(mTcpServerSocket != null){
            new Thread() {
                @Override
                public void run() {
                    super.run();
                    try {
                        for(Socket socket:mSocketList) {
                            socket.close();
                        }
                        mTcpServerSocket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }.start();
        }
    }

    /**
     * 播放pcm 实时流
     * @param buffer
     */
    private void playPcmStream(byte[] buffer) {
        if (mAudioTrack != null && buffer != null) {
            mAudioTrack.play();
            mAudioTrack.write(buffer, 0, buffer.length);
        }
    }

  private Handler mUiHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case HANDLER_MSG_PLAY_PCM:
                    playPcmStream((byte[]) msg.obj);
                    break;
                default:
                    break;
            }
        }
    };

 private class MyTcpListener  implements ITcpSocketListener{
        @Override
        public void onRec(Socket socket, byte[] buffer) {
          sendHandlerMsg(HANDLER_MSG_PLAY_PCM,0,buffer);
        }
    }
展开