Extract Audio from Video Using MediaMuxer

Extract Audio from Video Using MediaMuxer

 private boolean cloneMediaUsingMuxer(String srcMedia, String dstMediaPath,
                                      int expectedTrackCount, int degrees) throws IOException {
        // Set up MediaExtractor to read from the source.
        //AssetFileDescriptor srcFd = mResources.openRawResourceFd(srcMedia);
        MediaExtractor extractor = new MediaExtractor();
        extractor.setDataSource(srcMedia);
        int trackCount = extractor.getTrackCount();
        //assertEquals("wrong number of tracks", expectedTrackCount, trackCount);
        // Set up MediaMuxer for the destination.
        MediaMuxer muxer;
        muxer = new MediaMuxer(dstMediaPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
        // Set up the tracks.
        int audioTrackIndex = 0;
        //HashMap<Integer, Integer> indexMap = new HashMap<Integer, Integer>(trackCount);
        for (int i = 0; i < trackCount; i++) {
            extractor.selectTrack(i);
            MediaFormat format = extractor.getTrackFormat(i);
            String COMPRESSED_AUDIO_FILE_MIME_TYPE = format.getString(MediaFormat.KEY_MIME);

            if(COMPRESSED_AUDIO_FILE_MIME_TYPE.startsWith("audio/")) {
                audioTrackIndex = muxer.addTrack(format);
            }
            //indexMap.put(i, dstIndex);
        }
        // Copy the samples from MediaExtractor to MediaMuxer.
        boolean sawEOS = false;
        int bufferSize = MAX_SAMPLE_SIZE;
        int frameCount = 0;
        int offset = 100;
        ByteBuffer dstBuf = ByteBuffer.allocate(bufferSize);
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
        if (degrees >= 0) {
            muxer.setOrientationHint(degrees);
        }

        muxer.start();
        while (!sawEOS) {
            bufferInfo.offset = offset;
            bufferInfo.size = extractor.readSampleData(dstBuf, offset);
            if (bufferInfo.size < 0) {
                if (VERBOSE) {
                    Log.d(TAG, "saw input EOS.");
                }
                sawEOS = true;
                bufferInfo.size = 0;
            } else {
                bufferInfo.presentationTimeUs = extractor.getSampleTime();
                bufferInfo.flags = extractor.getSampleFlags();
                int trackIndex = extractor.getSampleTrackIndex();
                if(audioTrackIndex == trackIndex ) {
                    muxer.writeSampleData(trackIndex, dstBuf,
                            bufferInfo);
                }
                extractor.advance();
                frameCount++;
                if (VERBOSE) {
                    Log.d(TAG, "Frame (" + frameCount + ") " +
                            "PresentationTimeUs:" + bufferInfo.presentationTimeUs +
                            " Flags:" + bufferInfo.flags +
                            " TrackIndex:" + trackIndex +
                            " Size(KB) " + bufferInfo.size / 1024);
                }
            }
        }
        muxer.stop();
        muxer.release();
        //srcFd.close();
        return true;
    }