将PCM记录的数据写入.wav文件(java android)

2022-09-01 05:25:21

我正在使用AudioRecord在Android中记录16位PCM数据。记录数据并将其保存到文件后,我将其读回以将其另存为.wav文件。

问题是WAV文件被媒体播放器识别,但除了纯粹的噪音之外什么也播放不了。目前我最好的猜测是我的wav文件头不正确,但我一直无法看到问题到底是什么。(我认为这是因为我可以播放我在Audacity中记录的原始PCM数据)

以下是我用于读取原始PCM文件并将其另存为.wav的代码:

private void properWAV(File fileToConvert, float newRecordingID){
    try {
        long mySubChunk1Size = 16;
        int myBitsPerSample= 16;
        int myFormat = 1;
        long myChannels = 1;
        long mySampleRate = 22100;
        long myByteRate = mySampleRate * myChannels * myBitsPerSample/8;
        int myBlockAlign = (int) (myChannels * myBitsPerSample/8);

        byte[] clipData = getBytesFromFile(fileToConvert);

        long myDataSize = clipData.length;
        long myChunk2Size =  myDataSize * myChannels * myBitsPerSample/8;
        long myChunkSize = 36 + myChunk2Size;

        OutputStream os;        
        os = new FileOutputStream(new File("/sdcard/onefile/assessor/OneFile_Audio_"+ newRecordingID+".wav"));
        BufferedOutputStream bos = new BufferedOutputStream(os);
        DataOutputStream outFile = new DataOutputStream(bos);

        outFile.writeBytes("RIFF");                                 // 00 - RIFF
        outFile.write(intToByteArray((int)myChunkSize), 0, 4);      // 04 - how big is the rest of this file?
        outFile.writeBytes("WAVE");                                 // 08 - WAVE
        outFile.writeBytes("fmt ");                                 // 12 - fmt 
        outFile.write(intToByteArray((int)mySubChunk1Size), 0, 4);  // 16 - size of this chunk
        outFile.write(shortToByteArray((short)myFormat), 0, 2);     // 20 - what is the audio format? 1 for PCM = Pulse Code Modulation
        outFile.write(shortToByteArray((short)myChannels), 0, 2);   // 22 - mono or stereo? 1 or 2?  (or 5 or ???)
        outFile.write(intToByteArray((int)mySampleRate), 0, 4);     // 24 - samples per second (numbers per second)
        outFile.write(intToByteArray((int)myByteRate), 0, 4);       // 28 - bytes per second
        outFile.write(shortToByteArray((short)myBlockAlign), 0, 2); // 32 - # of bytes in one sample, for all channels
        outFile.write(shortToByteArray((short)myBitsPerSample), 0, 2);  // 34 - how many bits in a sample(number)?  usually 16 or 24
        outFile.writeBytes("data");                                 // 36 - data
        outFile.write(intToByteArray((int)myDataSize), 0, 4);       // 40 - how big is this data chunk
        outFile.write(clipData);                                    // 44 - the actual data itself - just a long string of numbers

        outFile.flush();
        outFile.close();

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

}


private static byte[] intToByteArray(int i)
    {
        byte[] b = new byte[4];
        b[0] = (byte) (i & 0x00FF);
        b[1] = (byte) ((i >> 8) & 0x000000FF);
        b[2] = (byte) ((i >> 16) & 0x000000FF);
        b[3] = (byte) ((i >> 24) & 0x000000FF);
        return b;
    }

    // convert a short to a byte array
    public static byte[] shortToByteArray(short data)
    {
        /*
         * NB have also tried:
         * return new byte[]{(byte)(data & 0xff),(byte)((data >> 8) & 0xff)};
         * 
         */

        return new byte[]{(byte)(data & 0xff),(byte)((data >>> 8) & 0xff)};
    }

我没有包括getBytesFromFile(),因为它占用了太多的空间,而且它是一种经过试验和测试的方法。无论如何,这是执行实际记录的代码:

public void run() { 
    Log.i("ONEFILE", "Starting main audio capture loop...");

    int frequency = 22100;
    int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    int audioEncoding = AudioFormat.ENCODING_PCM_16BIT; 

    final int bufferSize = AudioRecord.getMinBufferSize(frequency, channelConfiguration, audioEncoding); 

    AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency, channelConfiguration, audioEncoding, bufferSize);

    audioRecord.startRecording();
    ByteArrayOutputStream recData = new ByteArrayOutputStream(); 
    DataOutputStream dos = new DataOutputStream(recData);

    short[] buffer = new short[bufferSize];  
    audioRecord.startRecording();

    while (!stopped) {  
        int bufferReadResult = audioRecord.read(buffer, 0, bufferSize);

        for(int i = 0; i < bufferReadResult;i++) {
            try {
                dos.writeShort(buffer[i]);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }  
    audioRecord.stop();
    try {
        dos.flush();
        dos.close();
    } catch (IOException e1) {
        e1.printStackTrace();
    }

    audioRecord.stop();

    byte[] clipData = recData.toByteArray();

    File file = new File(audioOutputPath);
    if(file.exists())
        file.delete();
    file = new File(audioOutputPath);
    OutputStream os;
    try {
        os = new FileOutputStream(file);

        BufferedOutputStream bos = new BufferedOutputStream(os);
        DataOutputStream outFile = new DataOutputStream(bos);

        outFile.write(clipData);  

        outFile.flush();
        outFile.close();

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

请建议可能出错的地方。


答案 1

几个小时以来,我一直在为这个完全相同的问题而苦苦挣扎,我的问题主要是,当以16位录制时,您必须非常小心地将内容写入输出。WAV 文件需要小字节序格式的数据,但使用 writeShort 会将其作为大字节序写入输出。使用其他函数时,我也得到了有趣的结果,所以我回到了以正确的顺序写入字节,这很有效。

在调试此内容时,我广泛使用了十六进制编辑器。我可以建议你做同样的事情。另外,上面答案中的标头有效,我用它来检查我自己的代码,这个标头是相当万无一失的。


答案 2

根据标题是关注的,我已经遵循了这个代码(如果它以某种方式帮助你)。

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);

推荐