Android AudioTrack 播放 .wav 文件，只得到白噪声 [英] Android AudioTrack playing .wav file, getting only white noise

问题描述

当我使用以下代码播放文件时:

When I play a file with the following code:

private void PlayAudioFileViaAudioTrack(int ResId) throws IOException {

    int intSize = android.media.AudioTrack.getMinBufferSize(11025, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT);

    AudioTrack at = new AudioTrack(AudioManager.STREAM_MUSIC, 11025, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, intSize,
            AudioTrack.MODE_STREAM);

    int count = 256 * 1024; // 256 kb
    byte[] byteData = null;
    byteData = new byte[(int) count];
    InputStream in = null;
    AssetFileDescriptor fd = null;
    fd = mResources.openRawResourceFd(ResId);
    in = mResources.openRawResource(ResId);

    int bytesRead = 0, amount = 0;
    int size = (int) fd.getLength();
    at.play();
    while (bytesRead < size) {
        amount = in.read(byteData, 0, count);
        if (amount != -1) {
            at.write(byteData, 0, amount);
        }
    }
    in.close();
    at.stop();
    at.release();

}

我唯一听到的是静态的白噪声.我已经检查过我的 .wav 文件具有相同的属性(采样率、比特率).我对原始音频数据 (PCM) 了解不多，所以我想知道是否有人能看到我的代码有什么问题.

The only thing I hear is static, white noise. I've checked that my .wav file has the same properties (samplerate,bitrate). I don't have to much knowledge about raw audio data(PCM), so I was wondering if anyone could see what's wrong with my code.

推荐答案

从你的代码中我可以看到你只是从 wav 文件中读取数据并将它们导入到 AudioTrack 中.Wav 文件有一个小标题，您可以在此处看到 https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ 因此，您必须跳过标题并将文件描述符指向实际音频数据所在的正确位置.

from your code i can see that you just read data from the wav file and just import them to the AudioTrack. Wav files have a small header as you can see here https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ So you have to skip the header and point your file descriptor at the right place where the actual audio data are.

此外，当您播放音频文件并处理字节操作时，您应该注意 Endianess.看看这里在Android中使用AudioTrack播放WAV文件

Also when you playing an audio file and you are dealing with byte operations you should take care of the Endianess. Take a look here Using AudioTrack in Android to play a WAV file

在我的代码下方(缺少一些检查和 WAV 标题跳过)，它适用于 Nexus One 和 Galaxy S，具有频率为 8000Hz 和 16 位编码的 wav 文件.

Below my code (some checks and the WAV header skip are missing) that works in both Nexus One and Galaxy S with a wav file with frequency 8000Hz and 16 bit encoding.

public void playWav(){
    int minBufferSize = AudioTrack.getMinBufferSize(8000, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT);
    int bufferSize = 512;
    AudioTrack at = new AudioTrack(AudioManager.STREAM_MUSIC, 8000, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, minBufferSize, AudioTrack.MODE_STREAM);
    String filepath = Environment.getExternalStorageDirectory().getAbsolutePath();

    int i = 0;
    byte[] s = new byte[bufferSize];
    try {
        FileInputStream fin = new FileInputStream(filepath + "/REFERENCE.wav");
        DataInputStream dis = new DataInputStream(fin);

        at.play();
        while((i = dis.read(s, 0, bufferSize)) > -1){
            at.write(s, 0, i);

        }
        at.stop();
        at.release();
        dis.close();
        fin.close();

    } catch (FileNotFoundException e) {
        // TODO
        e.printStackTrace();
    } catch (IOException e) {
        // TODO
        e.printStackTrace();
    }       
}

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