Question

我正在尝试为Android Wear构建录音机应用程序。现在，我能够捕获手表上的音频，将其传输到手机并将其保存在文件中。但是，音频文件存在间隙或裁剪部分。

我发现这个问题与我的问题link1，link2有关，但他们无法帮助我。

这是我的代码：

首先，在手表方面，我使用channelAPI创建频道并成功将手表上捕获的音频发送到智能手机。

//here are the variables values that I used

//44100Hz is currently the only rate that is guaranteed to work on all devices
//but other rates such as 22050, 16000, and 11025 may work on some devices.

private static final int RECORDER_SAMPLE_RATE = 44100; 
private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
int BufferElements2Rec = 1024; 
int BytesPerElement = 2; 

//start the process of recording audio
private void startRecording() {

    recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
            RECORDER_SAMPLE_RATE, RECORDER_CHANNELS,
            RECORDER_AUDIO_ENCODING, BufferElements2Rec * BytesPerElement);

    recorder.startRecording();
    isRecording = true;
    recordingThread = new Thread(new Runnable() {
        public void run() {
            writeAudioDataToPhone();
        }
    }, "AudioRecorder Thread");
    recordingThread.start();
}

private void writeAudioDataToPhone(){

    short sData[] = new short[BufferElements2Rec];
    ChannelApi.OpenChannelResult result = Wearable.ChannelApi.openChannel(googleClient, nodeId, "/mypath").await();
    channel = result.getChannel();

    Channel.GetOutputStreamResult getOutputStreamResult = channel.getOutputStream(googleClient).await();
    OutputStream outputStream = getOutputStreamResult.getOutputStream();

    while (isRecording) {
        // gets the voice output from microphone to byte format

        recorder.read(sData, 0, BufferElements2Rec);
        try {
            byte bData[] = short2byte(sData);
            outputStream.write(bData);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    try {
        outputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

然后，在智能手机端，我从频道收到音频数据并将其写入PCM文件。

public void onChannelOpened(Channel channel) {
    if (channel.getPath().equals("/mypath")) {
        Channel.GetInputStreamResult getInputStreamResult = channel.getInputStream(mGoogleApiClient).await();
        inputStream = getInputStreamResult.getInputStream();

        writePCMToFile(inputStream);

        MainActivity.this.runOnUiThread(new Runnable() {
            public void run() {
                Toast.makeText(MainActivity.this, "Audio file received!", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

public void writePCMToFile(InputStream inputStream) {
    OutputStream outputStream = null;

    try {
        // write the inputStream to a FileOutputStream
        outputStream = new FileOutputStream(new File("/sdcard/wearRecord.pcm"));

        int read = 0;
        byte[] bytes = new byte[1024];

        while ((read = inputStream.read(bytes)) != -1) {
            outputStream.write(bytes, 0, read);
        }

        System.out.println("Done writing PCM to file!");

    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (inputStream != null) {
            try {
                inputStream.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if (outputStream != null) {
            try {
                // outputStream.flush();
                outputStream.close();
            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    }
}

我做错了什么或者你有什么建议在智能手机上实现完美的无间隙音频文件？提前谢谢。

Answer 1

我在你的代码中注意到你正在将所有内容读入一个short []数组，然后将其转换为byte []数组以供Channel API发送。您的代码还会在循环的每次迭代中创建一个新的byte []数组，这将为垃圾收集器创建大量工作。通常，您希望避免在循环内进行分配。

我会在顶部分配一个byte []数组，让AudioRecord类将它直接存储到byte []数组中（只需确保分配两倍于short的字节数），代码如下：

mAudioTemp = new byte[bufferSize];

int result;
while ((result = mAudioRecord.read(mAudioTemp, 0, mAudioTemp.length)) > 0) {
  try {
    mAudioStream.write(mAudioTemp, 0, result);
  } catch (IOException e) {
    Log.e(Const.TAG, "Write to audio channel failed: " + e);
  }
}

我还用1秒的音频缓冲区测试了这个，使用这样的代码，它运行得很好。我不确定最小缓冲区大小在开始出现问题之前是什么：

int bufferSize = Math.max(
  AudioTrack.getMinBufferSize(44100, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT),
  44100 * 2);

Android Wear Audio Recorder使用ChannelAPI

1 个答案: