目前我正在我的公司做一些关于 voip 应用程序的研究。

我们想在 amr 中记录设备麦克风的声音，对其进行加密并将数据发送到我们的服务器，另一端从服务器流式传输并解密。对于一些测试用例，我目前使用 MediaRecorder 在 amr 中录制声音。因为我想连续流式传输当前的声音，所以我不能使用文件来存储数据。所以我创建了一个管道并将其作为文件描述符提供给 MediaRecorder-Reference。

MediaRecorder mediaRecorder = createMediaRecorder();

    //make a pipe containing a read and write parcelFd
    try {
        ParcelFileDescriptor[] fdPair = ParcelFileDescriptor.createPipe();
        //get a handle to your read and write fd objects
        ParcelFileDescriptor readFd = fdPair[0];
        ParcelFileDescriptor writeFd = fdPair[1];
        //set the output to the write side of this pipe
        mediaRecorder.setOutputFile(writeFd.getFileDescriptor());
        //next create an input stream to read from the read side of the pipe.
        FileInputStream reader = new FileInputStream(readFd.getFileDescriptor());
        FileOutputStream writer = new FileOutputStream(writeFd.getFileDescriptor());

        //now to fill up a buffer with data, only do a simple read
        byte[] buffer = new byte[BUFSIZE];

        mediaRecorder.prepare();
        //by starting the mediarecorder, it will write into the writeFD
        mediaRecorder.start();

        Log.i(LOG_TAG, "Start Recording");
        while(_isRecording){
            int length = 0;
            while((length = reader.read(buffer)) > 0){
                writer.write(buffer, 0, length);
                _audioListener.onAudioRecorded(buffer, 0, length);
            }
        }

        Log.i(LOG_TAG, "Stop Recording");
        writer.flush();
        writer.close();
        reader.close();

        tearDownMediaRecorder(mediaRecorder);
    } catch (IOException e) {
        e.printStackTrace();
    }

AudioListener 会将读取的字节发送到我的 Activity，我在 Activity 中保存一个 MediaPlayer 实例，它应该读取数据并播放它。我知道听到我刚才说的话没有多大意义，但这只是为了测试我如何读取 MediaPlayer 中管道的内容。这就是我的 Activity 所做的。

ParcelFileDescriptor[] fdPair = ParcelFileDescriptor.createPipe();
            _readFd = fdPair[0];
//              _writer = new FileOutputStream(_writeFd.getFileDescriptor());
            _reader = new FileInputStream(_readFd.getFileDescriptor());

            _mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            _mediaPlayer.setOnCompletionListener(new OnCompletionListener() {

                @Override
                public void onCompletion(MediaPlayer mp) {
                    Log.i(LOG_TAG, "Media-Player Completed.");
                }
            });
            _mediaPlayer.setOnErrorListener(new OnErrorListener() {

                @Override
                public boolean onError(MediaPlayer mp, int what, int extra) {
                    Log.i(LOG_TAG, "Error-What: " + what);
                    return false;
                }
            });

            _mediaPlayer.setDataSource(_readFd.getFileDescriptor());
            Log.i(LOG_TAG, "Set Source of MediaPlayer");
            _mediaPlayer.prepare();
            _mediaPlayer.start();   
        }
        System.arraycopy(buffer, 0, mAudioTxBuffer, 0, bytesRead);

//_writer.write(mAudioTxBuffer); _reader.read(mAudioTxBuffer);

目前，如果我想播放接收到的字节，我会从 MediaPlayer 收到以下异常:

09-18 10:38:10.785: W/System.err(12136): java.io.IOException: setDataSourceFD failed.: status=0x80000000

我目前不知道是我理解有误还是代码中有错误。

感谢您的帮助。

最佳答案

The application needs to have the permission to write to external storage if the output file is written to the external storage, and also the permission to record audio. These permissions must be set in the application's AndroidManifest.xml file, with something like:

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.RECORD_AUDIO" />

关于android - 使用 MediaRecorder 录制音频并使用 MediaPlayer 同时播放，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18867933/