MacroblockType_PFrame.java

/***************************************
 *            ViPER-MPEG               *
 *  The Video Processing               *
 *         Evaluation Resource         *
 *             MPEG-1 Decoder          *
 * Distributed under the LGPL license  *
 *        Terms available at gnu.org.  *
 *                                     *
 *  Copyright University of Maryland,  *
 *                      College Park.  *
 ***************************************/

package edu.umd.cfar.lamp.mpeg1.video;

import java.io.*;

import edu.columbia.ee.flavor.*;
import edu.umd.cfar.lamp.mpeg1.*;

class MacroblockType_PFrame implements Parsable {
	private MacroblockType value = new MacroblockType();

	public void parse(Bitstream bitstream) throws IOException {
		boolean macroblock_quant, macroblock_motion_forward, macroblock_motion_backward, macroblock_pattern, macroblock_intra;

		switch (bitstream.nextbits(1)) {
		case 1:
			bitstream.skipbits(1);
			macroblock_quant = false;
			macroblock_motion_forward = true;
			macroblock_motion_backward = false;
			macroblock_pattern = true;
			macroblock_intra = false;
			break;
		default:
			switch (bitstream.nextbits(2)) {
			case 1:
				bitstream.skipbits(2);
				macroblock_quant = false;
				macroblock_motion_forward = false;
				macroblock_motion_backward = false;
				macroblock_pattern = true;
				macroblock_intra = false;
				break;
			default:
				switch (bitstream.nextbits(3)) {
				case 1:
					bitstream.skipbits(3);
					macroblock_quant = false;
					macroblock_motion_forward = true;
					macroblock_motion_backward = false;
					macroblock_pattern = false;
					macroblock_intra = false;
					break;
				default:
					switch (bitstream.nextbits(5)) {
					case 3:
						bitstream.skipbits(5);
						macroblock_quant = false;
						macroblock_motion_forward = false;
						macroblock_motion_backward = false;
						macroblock_pattern = false;
						macroblock_intra = true;
						break;
					case 2:
						bitstream.skipbits(5);
						macroblock_quant = true;
						macroblock_motion_forward = true;
						macroblock_motion_backward = false;
						macroblock_pattern = true;
						macroblock_intra = false;
						break;
					case 1:
						bitstream.skipbits(5);
						macroblock_quant = true;
						macroblock_motion_forward = false;
						macroblock_motion_backward = false;
						macroblock_pattern = true;
						macroblock_intra = false;
						break;
					default:
						switch (bitstream.nextbits(6)) {
						case 1:
							bitstream.skipbits(6);
							macroblock_quant = true;
							macroblock_motion_forward = false;
							macroblock_motion_backward = false;
							macroblock_pattern = false;
							macroblock_intra = true;
							break;
						default:
							throw new ParsingException(
									"VLC decode for MacroblockType_PFrame failed.");
						}
					}
				}
			}
		}
		value.setValues(macroblock_quant, macroblock_motion_forward,
				macroblock_motion_backward, macroblock_pattern,
				macroblock_intra);
	}

	public MacroblockType getValue() {
		return value;
	}
}