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I am using SimpleLameLibForAndroid to convert a pcm file that created using AudioRecord class in android,to mp3. I read the pcm file and encoded it into mp3 and then I write it in the file. the result mp3 file but is not correct and it has a lot of noise on it and really hard to understand that it was recorded pcm file. these are recorded audio specifications(pcm file):

    private static final int RECORDER_SAMPLERATE = 8000;
    private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
    private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;    
    int BufferElements2Rec = 1024; // want to play 2048 (2K) since 2 bytes we use only 1024
    int BytesPerElement = 2; // 2 bytes in 16bit format
    recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
    RECORDER_SAMPLERATE, RECORDER_CHANNELS,
    RECORDER_AUDIO_ENCODING, BufferElements2Rec * BytesPerElement);

and this is my code that uses liblame for encode mp3 and write it to file:

//Encoder.Builder(int inSamplerate,int outChannel,int outSampleRate,int outBitrate)
Encoder en = new Encoder.Builder(8000, 1,8000,128).quality(7).create();
private int PCM_BUF_SIZE = 8192;
private int MP3_SIZE = 8192;
private void readFile()  {
    File pcm = new File("/sdcard/voice8K16bitmono.pcm");
    File mp3 = new File("/sdcard/BOOOB.mp3");
    pcm.setReadable(true);
    mp3.setWritable(true);
    try {
        InputStream is = new FileInputStream(pcm);
        BufferedInputStream bis = new BufferedInputStream(is);
        bis.skip(44);//skip pcm header
        OutputStream os = new FileOutputStream(mp3);
        FileOutputStream fos = new FileOutputStream(mp3);
        int n_bytes_read ;
        int n_bytes_write;
        int i;

        byte mp3_buffer[] = new byte[MP3_SIZE];
        byte pcm_buffer1[] = new byte[PCM_BUF_SIZE * 2];

        do {
            n_bytes_read = bis.read(pcm_buffer1 , 0 , PCM_BUF_SIZE);
            if (n_bytes_read == 0){
                n_bytes_write = en.flush(mp3_buffer);
            }
            else{
                n_bytes_write = en.encodeBufferInterleaved(byte2short(pcm_buffer1) ,n_bytes_read , mp3_buffer);
            }

            bof.write(mp3_buffer, 0, PCM_BUF_SIZE);

        } while (n_bytes_read > 0);
        bis.close();
        fos.close();
        is.close();
        en.close();

    }catch (IOException e) {
        e.printStackTrace();
    }
}
private short[] byte2short(byte[] pcm_buffer1) {
    short[] shorts = new short[pcm_buffer1.length/2];
   ByteBuffer.wrap(pcm_buffer1).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts);
    return shorts;
}

how can i fix this code, is the bufferSizes true? using BufferedInputStream is correct? and...

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1 回答 1

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我昨天使用 lame 为我的应用程序实现了一个 PCM 到 MP3 编码器。我建议不要使用 SimpleLameLibForAndroid，而是自己将 lame 添加到您的项目中。如果您使用的是 Android Studio，如果您之前没有使用过 NDK，这里有一个很好的指南可以帮助您入门。

http://www.shaneenishry.com/blog/2014/08/17/ndk-with-android-studio/

至于实现 lame 本身，下面是一个非常好的指南，我遵循它来启动和运行我的应用程序。使用wrapper.c页面顶部的 .zip 文件。这公开了有用的方法，以便您可以避免所有讨厌的Stream东西Buffer。

http://developer.samsung.com/technical-doc/view.do?v=T000000090

综上所述，对跛脚编码器的实际调用非常简单，如下所示。

初始化（使用你喜欢的任何设置）：

public static final int NUM_CHANNELS = 1;
public static final int SAMPLE_RATE = 16000;
public static final int BITRATE = 64;
public static final int MODE = 1;
public static final int QUALITY = 7;
...

initEncoder(NUM_CHANNELS, SAMPLE_RATE, BITRATE, MODE, QUALITY);

对于编码（非常简单）：

int result = encodeFile(pcm.getPath(), mp3.getPath());
if (result == 0) {
    //success
}

当然，完成后会破坏编码器destroyEncoder()。

于 2015-12-16T21:47:56.490 回答