AC3SpecificBox.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.sampleentries.codec;

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

/**
 * This box contains parameters for AC-3 decoders. For more information see the
 * AC-3 specification "<code>ETSI TS 102 366 V1.2.1 (2008-08)</code>" at 
 * <a href="http://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.02.01_60/ts_102366v010201p.pdf>
 * http://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.02.01_60/ts_102366v010201p.pdf</a>.
 * 
 * @author in-somnia
 */
public class AC3SpecificBox extends CodecSpecificBox {

	private int fscod, bsid, bsmod, acmod, bitRateCode;
	private boolean lfeon;

	public AC3SpecificBox() {
		super("AC-3 Specific Box");
	}

	@Override
	public void decode(MP4InputStream in) throws IOException {
		final long l = in.readBytes(3);

		//2 bits fscod
		fscod = (int) ((l>>22)&0x3);
		//5 bits bsid
		bsid = (int) ((l>>17)&0x1F);
		//3 bits bsmod
		bsmod = (int) ((l>>14)&0x7);
		//3 bits acmod
		acmod = (int) ((l>>11)&0x7);
		//1 bit lfeon
		lfeon = ((l>>10)&0x1)==1;
		//5 bits bitRateCode
		bitRateCode = (int) ((l>>5)&0x1F);
		//5 bits reserved
	}

	/**
	 * This field has the same meaning and is set to the same value as the fscod
	 * field in the AC-3 bitstream.
	 * 
	 * @return the value of the 'fscod' field
	 */
	public int getFscod() {
		return fscod;
	}

	/**
	 * This field has the same meaning and is set to the same value as the bsid 
	 * field in the AC-3 bitstream.
	 * 
	 * @return the value of the 'bsid' field
	 */
	public int getBsid() {
		return bsid;
	}

	/**
	 * This field has the same meaning and is set to the same value as the bsmod
	 * field in the AC-3 bitstream.
	 * 
	 * @return the value of the 'acmod' field
	 */
	public int getBsmod() {
		return bsmod;
	}

	/**
	 * This field has the same meaning and is set to the same value as the acmod
	 * field in the AC-3 bitstream.
	 * 
	 * @return the value of the 'acmod' field
	 */
	public int getAcmod() {
		return acmod;
	}

	/**
	 * This field has the same meaning and is set to the same value as the lfeon
	 * field in the AC-3 bitstream.
	 * 
	 * @return the value of the 'lfeon' field
	 */
	public boolean isLfeon() {
		return lfeon;
	}

	/**
	 * This field indicates the data rate of the AC-3 bitstream in kbit/s, as 
	 * shown in the following table:
	 * <table>
	 * <tr><th>bit rate code</th><th>bit rate (kbit/s)</th></tr>
	 * <tr><td>0</td><td>32</td></tr>
	 * <tr><td>1</td><td>40</td></tr>
	 * <tr><td>2</td><td>48</td></tr>
	 * <tr><td>3</td><td>56</td></tr>
	 * <tr><td>4</td><td>64</td></tr>
	 * <tr><td>5</td><td>80</td></tr>
	 * <tr><td>6</td><td>96</td></tr>
	 * <tr><td>7</td><td>112</td></tr>
	 * <tr><td>8</td><td>128</td></tr>
	 * <tr><td>9</td><td>160</td></tr>
	 * <tr><td>10</td><td>192</td></tr>
	 * <tr><td>11</td><td>224</td></tr>
	 * <tr><td>12</td><td>256</td></tr>
	 * <tr><td>13</td><td>320</td></tr>
	 * <tr><td>14</td><td>384</td></tr>
	 * <tr><td>15</td><td>448</td></tr>
	 * <tr><td>16</td><td>512</td></tr>
	 * <tr><td>17</td><td>576</td></tr>
	 * <tr><td>18</td><td>640</td></tr>
	 * </table>
	 * 
	 * @return the bit rate code
	 */
	public int getBitRateCode() {
		return bitRateCode;
	}
}