ServeMp4.java

package com.googlecode.mp4parser;

import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.AbstractHandler;
import org.mp4parser.Container;
import org.mp4parser.muxer.Movie;
import org.mp4parser.muxer.Track;
import org.mp4parser.muxer.builder.DefaultMp4Builder;
import org.mp4parser.muxer.container.mp4.MovieCreator;
import org.mp4parser.muxer.tracks.ClippedTrack;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.channels.Channels;
import java.nio.channels.WritableByteChannel;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * User: sannies
 * Date: 10/28/12
 * Time: 11:08 AM
 * To change this template use File | Settings | File Templates.
 */
public class ServeMp4 extends AbstractHandler {

    Movie movie;

    public ServeMp4(Movie movie) {
        this.movie = movie;
    }

    public static void main(String[] args) throws Exception {
        Movie movie = MovieCreator.build("/home/sannies/CSI.S13E02.HDTV.x264-LOL.mp4");


        Server server = new Server(8080);
        server.setHandler(new ServeMp4(movie));
        server.start();
        server.join();
    }

    private static double correctTimeToSyncSample(Track track, double cutHere, boolean next) {
        double[] timeOfSyncSamples = new double[track.getSyncSamples().length];
        long currentSample = 0;
        double currentTime = 0;
        for (int i = 0; i < track.getSampleDurations().length; i++) {
            long delta = track.getSampleDurations()[i];
            if (Arrays.binarySearch(track.getSyncSamples(), currentSample + 1) >= 0) {
                // samples always start with 1 but we start with zero therefore +1
                timeOfSyncSamples[Arrays.binarySearch(track.getSyncSamples(), currentSample + 1)] = currentTime;
            }
            currentTime += (double) delta / (double) track.getTrackMetaData().getTimescale();
            currentSample++;
        }
        double previous = 0;
        for (double timeOfSyncSample : timeOfSyncSamples) {
            if (timeOfSyncSample > cutHere) {
                if (next) {
                    return timeOfSyncSample;
                } else {
                    return previous;
                }
            }
            previous = timeOfSyncSample;
        }
        return timeOfSyncSamples[timeOfSyncSamples.length - 1];
    }

    public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        String start = request.getParameter("start");
        List<Track> tracks = movie.getTracks();
        movie.setTracks(new LinkedList<Track>());
        // remove all tracks we will create new tracks from the old

        double startTime = Double.parseDouble(start);
        double endTime = (double) tracks.get(0).getDuration() / tracks.get(0).getTrackMetaData().getTimescale();

        boolean timeCorrected = false;

        // Here we try to find a track that has sync samples. Since we can only start decoding
        // at such a sample we SHOULD make sure that the start of the new fragment is exactly
        // such a frame
        for (Track track : tracks) {
            if (track.getSyncSamples() != null && track.getSyncSamples().length > 0) {
                if (timeCorrected) {
                    // This exception here could be a false positive in case we have multiple tracks
                    // with sync samples at exactly the same positions. E.g. a single movie containing
                    // multiple qualities of the same video (Microsoft Smooth Streaming file)

                    throw new RuntimeException("The startTime has already been corrected by another track with SyncSample. Not Supported.");
                }
                startTime = correctTimeToSyncSample(track, startTime, false);
                endTime = correctTimeToSyncSample(track, endTime, true);
                timeCorrected = true;
            }
        }

        for (Track track : tracks) {
            long currentSample = 0;
            double currentTime = 0;
            long startSample = -1;
            long endSample = -1;

            for (int i = 0; i < track.getSampleDurations().length; i++) {
                long delta = track.getSampleDurations()[i];

                if (currentTime <= startTime) {
                    // current sample is still before the new starttime
                    startSample = currentSample;
                }
                if (currentTime <= endTime) {
                    // current sample is after the new start time and still before the new endtime
                    endSample = currentSample;
                } else {
                    // current sample is after the end of the cropped video
                    break;
                }
                currentTime += (double) delta / (double) track.getTrackMetaData().getTimescale();
                currentSample++;
            }
            movie.addTrack(new ClippedTrack(track, startSample, endSample));
        }

        Container out = new DefaultMp4Builder().build(movie);
        response.setHeader("content-type", "video/mp4");
        WritableByteChannel reponse = Channels.newChannel(response.getOutputStream());
        out.writeContainer(reponse);
        reponse.close();


    }

}