问从android视频中提取MP3格式的音频

EN

public class AudioUtils {

private static final String TAG = "AudioUtils";
private static final int DEFAULT_BUFFER_SIZE = 1 * 1024 * 1024;

public void genVideoUsingMuxer(FileDescriptor srcPath, FileDescriptor dstPathFd, String dstPath, int startMs, int endMs, boolean useAudio, boolean useVideo) throws IOException {
    // Set up MediaExtractor to read from the source.
    MediaExtractor extractor = new MediaExtractor();
    extractor.setDataSource(srcPath);
    int trackCount = extractor.getTrackCount();
    // Set up MediaMuxer for the destination.
    MediaMuxer muxer;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        muxer = new MediaMuxer(dstPathFd, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    } else {
        muxer = new MediaMuxer(dstPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    }

    // Set up the tracks and retrieve the max buffer size for selected
    // tracks.
    HashMap<Integer, Integer> indexMap = new HashMap<Integer, Integer>(trackCount);
    int bufferSize = -1;
    for (int i = 0; i < trackCount; i++) {
        MediaFormat format = extractor.getTrackFormat(i);
        String mime = format.getString(MediaFormat.KEY_MIME);
        boolean selectCurrentTrack = false;
        if (mime.startsWith("audio/") && useAudio) {
            selectCurrentTrack = true;
        } else if (mime.startsWith("video/") && useVideo) {
            selectCurrentTrack = true;
        }
        if (selectCurrentTrack) {
            extractor.selectTrack(i);
            int dstIndex = muxer.addTrack(format);
            indexMap.put(i, dstIndex);
            if (format.containsKey(MediaFormat.KEY_MAX_INPUT_SIZE)) {
                int newSize = format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
                bufferSize = newSize > bufferSize ? newSize : bufferSize;
            }
        }
    }
    if (bufferSize < 0) {
        bufferSize = DEFAULT_BUFFER_SIZE;
    }
    // Set up the orientation and starting time for extractor.
    MediaMetadataRetriever retrieverSrc = new MediaMetadataRetriever();
    retrieverSrc.setDataSource(srcPath);
    String degreesString = retrieverSrc.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_ROTATION);
    if (degreesString != null) {
        int degrees = Integer.parseInt(degreesString);
        if (degrees >= 0) {
            muxer.setOrientationHint(degrees);
        }
    }
    if (startMs > 0) {
        extractor.seekTo(startMs * 1000, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
    }
    // Copy the samples from MediaExtractor to MediaMuxer. We will loop
    // for copying each sample and stop when we get to the end of the source
    // file or exceed the end time of the trimming.
    int offset = 0;
    int trackIndex = -1;
    ByteBuffer dstBuf = ByteBuffer.allocate(bufferSize);
    MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
    muxer.start();
    while (true) {
        bufferInfo.offset = offset;
        bufferInfo.size = extractor.readSampleData(dstBuf, offset);
        if (bufferInfo.size < 0) {
            Log.d(TAG, "Saw input EOS.");
            bufferInfo.size = 0;
            break;
        } else {
            bufferInfo.presentationTimeUs = extractor.getSampleTime();
            if (endMs > 0 && bufferInfo.presentationTimeUs > (endMs * 1000)) {
                Log.d(TAG, "The current sample is over the trim end time.");
                break;
            } else {
                bufferInfo.flags = extractor.getSampleFlags();
                trackIndex = extractor.getSampleTrackIndex();
                muxer.writeSampleData(indexMap.get(trackIndex), dstBuf, bufferInfo);
                extractor.advance();
            }
        }
    }
    muxer.stop();
    muxer.release();
    return;
}

}

  new AudioUtils().genVideoUsingMuxer(inputVideoFileDescriptor, outputAudioFileDescriptor, destPath, -1, -1, true, false);

String destPath = Environment.getExternalStoragePublicDirectory("") + "/AudFolder2/asd.mp3"
try {
        FileDescriptor outputAudioFileDescriptor = getActivity().getContentResolver().openFileDescriptor(outputAudioUri, "w").getFileDescriptor();
        
  FileDescriptor inputVideoFileDescriptor = getActivity().getContentResolver().openFileDescriptor(Uri.parse(inputVideoUri), "r").getFileDescriptor();

        new AudioUtils().genVideoUsingMuxer(pfdVideo.getFileDescriptor(), pfdAudio.getFileDescriptor(), destPath, -1, -1, true, false);
    } catch (IOException e) {
        e.printStackTrace();
        Log.e(TAG, "saveAudioToDevice: ERROR = "+ e.getMessage() );
    }