FilePartitionBox.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.fd;

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

public class FilePartitionBox extends FullBox {

	private int itemID, packetPayloadSize, fecEncodingID, fecInstanceID,
			maxSourceBlockLength, encodingSymbolLength, maxNumberOfEncodingSymbols;
	private String schemeSpecificInfo;
	private int[] blockCounts;
	private long[] blockSizes;

	public FilePartitionBox() {
		super("File Partition Box");
	}

	@Override
	public void decode(MP4InputStream in) throws IOException {
		super.decode(in);

		itemID = (int) in.readBytes(2);
		packetPayloadSize = (int) in.readBytes(2);
		in.skipBytes(1); //reserved
		fecEncodingID = in.read();
		fecInstanceID = (int) in.readBytes(2);
		maxSourceBlockLength = (int) in.readBytes(2);
		encodingSymbolLength = (int) in.readBytes(2);
		maxNumberOfEncodingSymbols = (int) in.readBytes(2);
		schemeSpecificInfo = new String(Base64Decoder.decode(in.readTerminated((int) getLeft(in), 0)));

		final int entryCount = (int) in.readBytes(2);
		blockCounts = new int[entryCount];
		blockSizes = new long[entryCount];
		for(int i = 0; i<entryCount; i++) {
			blockCounts[i] = (int) in.readBytes(2);
			blockSizes[i] = (int) in.readBytes(4);
		}
	}

	/**
	 * The item ID references the item in the item location box that the file
	 * partitioning applies to.
	 *
	 * @return the item ID
	 */
	public int getItemID() {
		return itemID;
	}

	/**
	 * The packet payload size gives the target ALC/LCT or FLUTE packet payload
	 * size of the partitioning algorithm. Note that UDP packet payloads are
	 * larger, as they also contain ALC/LCT or FLUTE headers.
	 * 
	 * @return the packet payload size
	 */
	public int getPacketPayloadSize() {
		return packetPayloadSize;
	}

	/**
	 * The FEC encoding ID is subject to IANA registration (see RFC 3452). Note
	 * that
	 * - value zero corresponds to the "Compact No-Code FEC scheme" also known
	 * as "Null-FEC" (RFC 3695);
	 * - value one corresponds to the "MBMS FEC" (3GPP TS 26.346);
	 * - for values in the range of 0 to 127, inclusive, the FEC scheme is
	 * Fully-Specified, whereas for values in the range of 128 to 255,
	 * inclusive, the FEC scheme is Under-Specified.
	 *
	 * @return the FEC encoding ID
	 */
	public int getFECEncodingID() {
		return fecEncodingID;
	}

	/**
	 * The FEC instance ID provides a more specific identification of the FEC
	 * encoder being used for an Under-Specified FEC scheme. This value should
	 * be set to zero for Fully-Specified FEC schemes and shall be ignored when
	 * parsing a file with an FEC encoding ID in the range of 0 to 127,
	 * inclusive. The FEC instance ID is scoped by the FEC encoding ID. See RFC
	 * 3452 for further details.
	 *
	 * @return the FEC instance ID
	 */
	public int getFECInstanceID() {
		return fecInstanceID;
	}

	/**
	 * The maximum source block length gives the maximum number of source
	 * symbols per source block.
	 *
	 * @return the maximum source block length
	 */
	public int getMaxSourceBlockLength() {
		return maxSourceBlockLength;
	}

	/**
	 * The encoding symbol length gives the size (in bytes) of one encoding
	 * symbol. All encoding symbols of one item have the same length, except the
	 * last symbol which may be shorter.
	 *
	 * @return the encoding symbol length
	 */
	public int getEncodingSymbolLength() {
		return encodingSymbolLength;
	}

	/**
	 * The maximum number of encoding symbols  that can be generated for a
	 * source block for those FEC schemes in which the maximum number of
	 * encoding symbols is relevant, such as FEC encoding ID 129 defined in RFC
	 * 3452. For those FEC schemes in which the maximum number of encoding
	 * symbols is not relevant, the semantics of this field is unspecified.
	 *
	 * @return the maximum number of encoding symbols
	 */
	public int getMaxNumberOfEncodingSymbols() {
		return maxNumberOfEncodingSymbols;
	}

	/**
	 * The scheme specific info is a String of the scheme-specific object 
	 * transfer information (FEC-OTI-Scheme-Specific-Info). The definition of 
	 * the information depends on the EC encoding ID.
	 * 
	 * @return the scheme specific info
	 */
	public String getSchemeSpecificInfo() {
		return schemeSpecificInfo;
	}

	/**
	 * A block count indicates the number of consecutive source blocks with a
	 * specified size.
	 *
	 * @return all block counts
	 */
	public int[] getBlockCounts() {
		return blockCounts;
	}

	/**
	 * A block size indicates the size of a block (in bytes). A block_size that 
	 * is not a multiple of the encoding symbol length indicates with Compact 
	 * No-Code FEC that the last source symbols includes padding that is not 
	 * stored in the item. With MBMS FEC (3GPP TS 26.346) the padding may extend
	 * across multiple symbols but the size of padding should never be more than
	 * the encoding symbol length.
	 *
	 * @return all block sizes
	 */
	public long[] getBlockSizes() {
		return blockSizes;
	}
}