如何转换音频生Android中后手 [英] How convert audio raw to flac in Android

问题描述

我记录带班audoiRecord音频。现在我想转换音频原始文件为* FLAC格式。我转换*原始文件为WAV下一方式：

I recording audio with class audoiRecord. Now I want convert audio raw file to *flac format. I convert *raw file to wav next way:

private void copyWaveFile(String inFilename,String outFilename){
    FileInputStream in = null;
    FileOutputStream out = null;
    long totalAudioLen = 0;
    long totalDataLen = totalAudioLen + 36;
    long longSampleRate = sampleRate;
    int channels = 2;
    long byteRate = RECORDER_BPP * sampleRate * channels/8;
    byte[] data_pcm = new byte[mAudioBufferSize];
    try {
        in = new FileInputStream(inFilename);
        out = new FileOutputStream(outFilename);
        totalAudioLen = in.getChannel().size();
        totalDataLen = totalAudioLen + 36;
        Log.i(TAG,"File size: " + totalDataLen);
        WriteWaveFileHeader(out, totalAudioLen, totalDataLen,
        longSampleRate, channels, byteRate);
        while(in.read(data_pcm) != -1){
            out.write(data_pcm);
        }
        in.close();
        out.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

这件code是负责文件标题

This piece of code is responsible for the file header

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);
}

我不明白什么应该是* FLAC文件的参数

I do not understand what should be the parameters of the *flac file

推荐答案

您需要一间codeR到PCM数据转换成FLAC格式。你不能只是改变标题，并期望内容为后手工作。

You need an encoder to convert pcm data to flac format. You cannot just change the header and expect the content to work as flac.

Android的（至少到4.1），不包括FLAC连接codeR，虽然有3.1起（资料来源支持的德codeR：的 http://developer.android.com/guide/appendix/media-formats.html ）。

Android (at least till 4.1) does not include a FLAC encoder, although there is a decoder supported from 3.1 onwards (Source: http://developer.android.com/guide/appendix/media-formats.html).

我没有直接的经验，但看到人们使用的ffmpeg作为后手EN $ C $铬。该项目 audioboo-的Andr​​oid ，其中包含本地libFLAC / libFLAC ++ EN codeR，看起来很有趣

I do not have direct experience, but have seen people use ffmpeg as a flac encoder. This project audioboo-android, which contains the native libFLAC/libFLAC++ encoder, looks interesting.

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