JcodecMp4VideoMuxer.java

public class JcodecMp4VideoMuxer implements VideoMuxer {
    private FileChannelWrapper mChannelWrapper;
    private MP4Muxer mMp4Muxer;
    private FramesMP4MuxerTrack mMp4Track;
    private ArrayList<ByteBuffer> mSpsList;
    private ArrayList<ByteBuffer> mPpsList;

    @Override
    public boolean initialize() {
        mSpsList = new ArrayList<ByteBuffer>();
        mPpsList = new ArrayList<ByteBuffer>();

        try {
            mChannelWrapper = NIOUtils.writableFileChannel(getOutputFilePath());
            mMp4Muxer       = new MP4Muxer(mChannelWrapper, Brand.MP4);
            mMp4Track       = mMp4Muxer.addTrackForCompressed(TrackType.VIDEO, 
                getFrameRate());
            // dump to disk every 2 seconds
            mMp4Track.setTgtChunkDuration(new Rational(2, 1), Unit.SEC);
            initialized = true;
            return true;
        } catch (IOException e) {
            Crashlytics.logException(e);
            e.printStackTrace();
        }

        return false;
    }

    void addFrame(@NotNull Frame frame) {
        long timescale = getFrameRate();
        ByteBuffer buffer = ByteBuffer.wrap(frame.getData());

        H264Utils.encodeMOVPacket(buffer, mSpsList, mPpsList);

        try {
            frameNo++;
            sumDuration += duration;
            mMp4Track.addFrame(new MP4Packet(buffer, 
                               frame.getPresentationTimeUs(), 
                               timescale, 
                               1, 
                               frameNo, 
                               frame.isSyncFrame(), 
                               null, 
                               frame.getPresentationTimeUs(), 0));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    boolean finalizeTrack() {
        boolean success = true;

        if (mSpsList.size() > 0 && mPpsList.size() > 0 && initialized) {
            mMp4Track.addSampleEntry(H264Utils.createMOVSampleEntry(mSpsList, mPpsList));

            try {
                mMp4Muxer.writeHeader();
            } catch (IOException e) {
                success = false;
                e.printStackTrace();
            }
        } else {
            success = false;
        }

        NIOUtils.closeQuietly(mChannelWrapper);

        try {
            mChannelWrapper.close();
        } catch (IOException e) {
            success = false;
            e.printStackTrace();
        }

        frameNo = 0;
        initialized = false;

        return success;
    }
}