Android：使记录的pcm原始数据可播放

Question

我正在开发一个Android应用程序，它支持使用以下代码录制音频，示例可以在这里找到：

http://developer.samsung.com/technical-doc/view.do;jsessionid=tT01JrgM5DRC15pN56v20xzJXcDYv7hZVLvPhT0zJ4kfvSc1TlTM!-846162528?v=T000000090

变量：

   private static final int RECORDER_BPP = 16;
   private static final int RECORDER_SAMPLERATE = 22050;
   private static final int RECORDER_CHANNELS =       AudioFormat.CHANNEL_IN_MONO;
   private static final int RECORDER_CHANNELS_NUMBER = 1;
   private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
   private AudioRecord recorder = null;
   private short[] mBuffer;
   private int bufferSize = 0;
   private boolean IsRecording = false;

为bufferSize分配一个值：

 bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,
                    AudioFormat.CHANNEL_IN_MONO,
                    AudioFormat.ENCODING_PCM_16BIT);

创建录像机：

 recorder = new AudioRecord(source, RECORDER_SAMPLERATE, RECORDER_CHANNELS,RECORDER_AUDIO_ENCODING, bufferSize);

源指示要使用的麦克风。

将收到的内容存储在原始文件中：

    new Thread(new Runnable() {
    @Override
    public void run() {
    DataOutputStream output = null;
    try {
    output = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(new File(getTempFilename()))));
    while (IsRecording) {
    int readSize = recorder.read(mBuffer, 0, mBuffer.length);
    for (int i = 0; i < readSize; i++) {
    output.writeShort(mBuffer[i]);
    } 
    }
    } catch (IOException e) {
    Toast.makeText(mContext, e.getMessage(), Toast.LENGTH_SHORT).show();
    } finally {
    if (output != null) {
    try {
    output.flush();
    } catch (IOException e) {
    Toast.makeText(mContext, e.getMessage(), Toast.LENGTH_SHORT).show();
    } finally { 
    try {
    output.close();
    } catch (IOException e) {
    Toast.makeText(mContext, e.getMessage(), Toast.LENGTH_SHORT).show();
    }
    }
    }
    }
    }
    }).start();   

我想要：

1. 使用android.media.MediaPlayer播放录制的音频
2. 在另一个活动中，将原始源编码为mp3。

根据上面的页面，我可以编译Lame库并创建包装器。 因此，这个原始文件可以编码为mp3而没有任何问题，但我找不到如何在编码之前使这个原始源可播放的方法。 找到的原始创建波形头的解决方案无法使用。

有人有解决方案吗？

更新：为了创建标题我试过这个：...

in = new FileInputStream(inFilename);
                        totalAudioLen = in.getChannel().size();
                        totalDataLen = totalAudioLen + 36;
long longSampleRate = RECORDER_SAMPLERATE;
                int channels = 1;
                long byteRate = RECORDER_BPP * RECORDER_SAMPLERATE * channels/8;

...
WriteWaveFileHeader（out，totalAudioLen，totalDataLen，longSampleRate，channels，byteRate）;

private void WriteWaveFileHeader(
                        FileOutputStream out, long totalAudioLen,
                        long totalDataLen, long longSampleRate, int channels,
                        long byteRate) throws IOException {
                byte[] header = new byte[44];

                header[0] = 'R';  // RIFF/WAVE header
                header[1] = 'I';
                header[2] = 'F';
                header[3] = 'F';
                header[4] = (byte) (totalDataLen & 0xff);
                header[5] = (byte) ((totalDataLen >> 8) & 0xff);
                header[6] = (byte) ((totalDataLen >> 16) & 0xff);
                header[7] = (byte) ((totalDataLen >> 24) & 0xff);
                header[8] = 'W';
                header[9] = 'A';
                header[10] = 'V';
                header[11] = 'E';
                header[12] = 'f';  // 'fmt ' chunk
                header[13] = 'm';
                header[14] = 't';
                header[15] = ' ';
                header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
                header[17] = 0;
                header[18] = 0;
                header[19] = 0;
                header[20] = 1;  // format = 1
                header[21] = 0;
                header[22] = (byte) channels;
                header[23] = 0;
                header[24] = (byte) (longSampleRate & 0xff);
                header[25] = (byte) ((longSampleRate >> 8) & 0xff);
                header[26] = (byte) ((longSampleRate >> 16) & 0xff);
                header[27] = (byte) ((longSampleRate >> 24) & 0xff);
                header[28] = (byte) (byteRate & 0xff);
                header[29] = (byte) ((byteRate >> 8) & 0xff);
                header[30] = (byte) ((byteRate >> 16) & 0xff);
                header[31] = (byte) ((byteRate >> 24) & 0xff);
                header[32] = (byte) (2 * 16 / 8);  // block align
                header[33] = 0;
                header[34] = RECORDER_BPP;  // bits per sample
                header[35] = 0;
                header[36] = 'd';
                header[37] = 'a';
                header[38] = 't';
                header[39] = 'a';
                header[40] = (byte) (totalAudioLen & 0xff);
                header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
                header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
                header[43] = (byte) ((totalAudioLen >> 24) & 0xff);

                out.write(header, 0, 44); 
        }

结果是一个嘈杂的波形文件

谢谢

Answer 1

如果你得到一个嘈杂的WAV，原因可能是你的16位样本的字节序问题。 在编写它们时尝试调整周围的字节，如下所示：

int readSize = recorder.read(mBuffer, 0, mBuffer.length);
for (int i = 0; i < readSize; i++) {
    output.writeShort(((mBuffer[i] >> 8) & 255) | (mBuffer[i] << 8));
} 

Answer 2

在这里，这是我的代码，它适合我（记录原始pcm音频并保存，然后用audiotrack播放）：

public class MainActivity extends Activity
{
    AudioRecord record = null;
    AudioTrack track = null;

    boolean isRecording;
    int sampleRate = 44100;

    Button startRecord, stopRecord, playRecord = null;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setVolumeControlStream(AudioManager.MODE_IN_COMMUNICATION);
        startRecord = (Button) findViewById(R.id.start_recording);
        stopRecord = (Button) findViewById(R.id.stop_recording);
        playRecord = (Button) findViewById(R.id.play_recording);
        startRecord.setOnClickListener(new StartRecordListener());
        stopRecord.setOnClickListener(new StopRecordListener());
        playRecord.setOnClickListener(new PlayRecordListener());

        stopRecord.setEnabled(false);
    }

    private void startRecord()
    {
        File recordFile = new File(Environment.getExternalStorageDirectory(), "Record.pcm");
        try
        {
            recordFile.createNewFile();

            OutputStream outputStream = new FileOutputStream(recordFile);
            BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream);
            DataOutputStream dataOutputStream = new DataOutputStream(bufferedOutputStream);

            int minBufferSize = AudioRecord.getMinBufferSize(sampleRate, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);

            short[] audioData = new short[minBufferSize];

            record = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRate, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT,
                                     minBufferSize);
            record.startRecording();

            while (isRecording)
            {
                int numberOfShort = record.read(audioData, 0, minBufferSize);
                for (int i = 0; i < numberOfShort; i++)
                {
                    dataOutputStream.writeShort(audioData[i]);
                }
            }
            record.stop();
            dataOutputStream.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    public void playRecord()
    {
        File recordFile = new File(Environment.getExternalStorageDirectory(), "Record.pcm");

        int shortSizeInBytes = Short.SIZE / Byte.SIZE;
        int bufferSizeInBytes = (int) (recordFile.length() / shortSizeInBytes);
        short[] audioData = new short[bufferSizeInBytes];
        try
        {
            InputStream inputStream = new FileInputStream(recordFile);
            BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);
            DataInputStream dataInputStream = new DataInputStream(bufferedInputStream);

            int i = 0;
            while (dataInputStream.available() > 0)
            {
                audioData[i] = dataInputStream.readShort();
                i++;
            }

            dataInputStream.close();

            track = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRate, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
                                   bufferSizeInBytes, AudioTrack.MODE_STREAM);

            track.play();
            track.write(audioData, 0, bufferSizeInBytes);
        }
        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }


    public class StartRecordListener implements View.OnClickListener
    {
        @Override
        public void onClick(View v)
        {
            Thread recordThread = new Thread(new Runnable()
            {
                @Override
                public void run()
                {
                    isRecording = true;
                    MainActivity.this.startRecord();
                }
            });
            recordThread.start();
            startRecord.setEnabled(false);
            stopRecord.setEnabled(true);
        }
    }

    public class StopRecordListener implements View.OnClickListener
    {
        @Override
        public void onClick(View v)
        {
            isRecording = false;
            startRecord.setEnabled(true);
            stopRecord.setEnabled(false);
        }
    }

    public class PlayRecordListener implements View.OnClickListener
    {
        @Override
        public void onClick(View v)
        {
            MainActivity.this.playRecord();
        }
    }
}

XML布局包含3个按钮，其中包含以下ID：start_recording，stop_recording，play_recording

并添加以下权限：

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

祝你好运，我希望你没关系，我在上面的代码中使用了3个按钮。