MovieHeaderBox.java

/*
 *  Copyright (C) 2011 in-somnia
 * 
 *  This file is part of JAAD.
 * 
 *  JAAD is free software; you can redistribute it and/or modify it 
 *  under the terms of the GNU Lesser General Public License as 
 *  published by the Free Software Foundation; either version 3 of the 
 *  License, or (at your option) any later version.
 *
 *  JAAD is distributed in the hope that it will be useful, but WITHOUT 
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General 
 *  Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library.
 *  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sourceforge.jaad.mp4.boxes.impl;

import net.sourceforge.jaad.mp4.boxes.FullBox;
import net.sourceforge.jaad.mp4.MP4InputStream;
import java.io.IOException;
import net.sourceforge.jaad.mp4.boxes.Utils;

/**
 * The movie header box defines overall information which is media-independent,
 * and relevant to the entire presentation considered as a whole.
 * @author in-somnia
 */
public class MovieHeaderBox extends FullBox {

	private long creationTime, modificationTime, timeScale, duration;
	private double rate, volume;
	private double[] matrix;
	private long nextTrackID;

	public MovieHeaderBox() {
		super("Movie Header Box");
		matrix = new double[9];
	}

	@Override
	public void decode(MP4InputStream in) throws IOException {
		super.decode(in);
		final int len = (version==1) ? 8 : 4;
		creationTime = in.readBytes(len);
		modificationTime = in.readBytes(len);
		timeScale = in.readBytes(4);
		duration = Utils.detectUndetermined(in.readBytes(len));

		rate = in.readFixedPoint(16, 16);
		volume = in.readFixedPoint(8, 8);

		in.skipBytes(10); //reserved

		for(int i = 0; i<9; i++) {
			if(i<6) matrix[i] = in.readFixedPoint(16, 16);
			else matrix[i] = in.readFixedPoint(2, 30);
		}

		in.skipBytes(24); //reserved

		nextTrackID = in.readBytes(4);
	}

	/**
	 * The creation time is an integer that declares the creation time of the
	 * presentation in seconds since midnight, Jan. 1, 1904, in UTC time.
	 * @return the creation time
	 */
	public long getCreationTime() {
		return creationTime;
	}

	/**
	 * The modification time is an integer that declares the most recent time
	 * the presentation was modified in seconds since midnight, Jan. 1, 1904,
	 * in UTC time.
	 */
	public long getModificationTime() {
		return modificationTime;
	}

	/**
	 * The time-scale is an integer that specifies the time-scale for the entire
	 * presentation; this is the number of time units that pass in one second.
	 * For example, a time coordinate system that measures time in sixtieths of
	 * a second has a time scale of 60.
	 * @return the time-scale
	 */
	public long getTimeScale() {
		return timeScale;
	}

	/**
	 * The duration is an integer that declares length of the presentation (in
	 * the indicated timescale). This property is derived from the
	 * presentation's tracks: the value of this field corresponds to the
	 * duration of the longest track in the presentation. If the duration cannot
	 * be determined then duration is set to -1.
	 * @return the duration of the longest track
	 */
	public long getDuration() {
		return duration;
	}

	/**
	 * The rate is a floting point number that indicates the preferred rate
	 * to play the presentation; 1.0 is normal forward playback
	 * @return the playback rate
	 */
	public double getRate() {
		return rate;
	}

	/**
	 * The volume is a floating point number that indicates the preferred
	 * playback volume: 0.0 is mute, 1.0 is normal volume.
	 * @return the volume
	 */
	public double getVolume() {
		return volume;
	}

	/**
	 * Provides a transformation matrix for the video:
	 * [A,B,U,C,D,V,X,Y,W]
	 * A: width scale
	 * B: width rotate
	 * U: width angle
	 * C: height rotate
	 * D: height scale
	 * V: height angle
	 * X: position from left
	 * Y: position from top
	 * W: divider scale (restricted to 1.0)
	 *
	 * The normal values for scale are 1.0 and for rotate 0.0.
	 * The angles are restricted to 0.0.
	 *
	 * @return the transformation matrix for the video
	 */
	public double[] getTransformationMatrix() {
		return matrix;
	}

	/**
	 * The next-track-ID is a non-zero integer that indicates a value to use
	 * for the track ID of the next track to be added to this presentation. Zero
	 * is not a valid track ID value. The value shall be larger than the largest
	 * track-ID in use. If this value is equal to all 1s (32-bit), and a new
	 * media track is to be added, then a search must be made in the file for an
	 * unused track identifier.
	 * @return the ID for the next track
	 */
	public long getNextTrackID() {
		return nextTrackID;
	}
}