ShortenExample.java

package com.googlecode.mp4parser;

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.AppendTrack;
import org.mp4parser.muxer.tracks.ClippedTrack;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

/**
 * Shortens/Crops a track
 */
public class ShortenExample {


    public static void main(String[] args) throws IOException {
        //Movie movie = new MovieCreator().build(new RandomAccessFile("/home/sannies/suckerpunch-distantplanet_h1080p/suckerpunch-distantplanet_h1080p.mov", "r").getChannel());
        Movie movie = MovieCreator.build("c:\\dev\\mp4parser\\34d91f42f4754c8ba12a5af279e10f77.mp4");

        List<Track> tracks = movie.getTracks();
        movie.setTracks(new LinkedList<Track>());
        // remove all tracks we will create new tracks from the old

        double startTime1 = 10;
        double endTime1 = 20;
        double startTime2 = 30;
        double endTime2 = 40;

        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.");
                }
                startTime1 = correctTimeToSyncSample(track, startTime1, false);
                endTime1 = correctTimeToSyncSample(track, endTime1, true);
                startTime2 = correctTimeToSyncSample(track, startTime2, false);
                endTime2 = correctTimeToSyncSample(track, endTime2, true);
                timeCorrected = true;
            }
        }

        for (Track track : tracks) {
            long currentSample = 0;
            double currentTime = 0;
            double lastTime = -1;
            long startSample1 = -1;
            long endSample1 = -1;
            long startSample2 = -1;
            long endSample2 = -1;

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


                if (currentTime > lastTime && currentTime <= startTime1) {
                    // current sample is still before the new starttime
                    startSample1 = currentSample;
                }
                if (currentTime > lastTime && currentTime <= endTime1) {
                    // current sample is after the new start time and still before the new endtime
                    endSample1 = currentSample;
                }
                if (currentTime > lastTime && currentTime <= startTime2) {
                    // current sample is still before the new starttime
                    startSample2 = currentSample;
                }
                if (currentTime > lastTime && currentTime <= endTime2) {
                    // current sample is after the new start time and still before the new endtime
                    endSample2 = currentSample;
                }
                lastTime = currentTime;
                currentTime += (double) delta / (double) track.getTrackMetaData().getTimescale();
                currentSample++;
            }
            movie.addTrack(new AppendTrack(new ClippedTrack(track, startSample1, endSample1), new ClippedTrack(track, startSample2, endSample2)));
        }
        long start1 = System.currentTimeMillis();
        Container out = new DefaultMp4Builder().build(movie);
        long start2 = System.currentTimeMillis();
        FileOutputStream fos = new FileOutputStream(String.format("output-%f-%f--%f-%f.mp4", startTime1, endTime1, startTime2, endTime2));
        FileChannel fc = fos.getChannel();
        out.writeContainer(fc);

        fc.close();
        fos.close();
        long start3 = System.currentTimeMillis();
        System.err.println("Building IsoFile took : " + (start2 - start1) + "ms");
        System.err.println("Writing IsoFile took  : " + (start3 - start2) + "ms");
        System.err.println("Writing IsoFile speed : " + (new File(String.format("output-%f-%f--%f-%f.mp4", startTime1, endTime1, startTime2, endTime2)).length() / (start3 - start2) / 1000) + "MB/s");
    }


    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];
    }


}