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Pure Java implementation of video/audio codecs and formats

There is a newer version: 0.2.5

package net.sourceforge.jaad.aac.gain;
import static java.lang.System.arraycopy;

import org.jcodec.platform.Platform;

import net.sourceforge.jaad.aac.AACException;
import net.sourceforge.jaad.aac.syntax.IBitStream;
import net.sourceforge.jaad.aac.syntax.ICSInfo.WindowSequence;

/**
 * This class is part of JAAD ( jaadec.sourceforge.net ) that is distributed
 * under the Public Domain license. Code changes provided by the JCodec project
 * are distributed under FreeBSD license.
 * 
 * @author in-somnia
 */
public class GainControl implements GCConstants {

	private final int frameLen, lbLong, lbShort;
	private final IMDCT imdct;
	private final IPQF ipqf;
	private final float[] buffer1, _function;
	private final float[][] buffer2, overlap;
	private int maxBand;
	private int[][][] level, levelPrev;
	private int[][][] location, locationPrev;

	public GainControl(int frameLen) {
		this.frameLen = frameLen;
		lbLong = frameLen/BANDS;
		lbShort = lbLong/8;
		imdct = new IMDCT(frameLen);
		ipqf = new IPQF();
		levelPrev = new int[0][][];
		locationPrev = new int[0][][];
		buffer1 = new float[frameLen/2];
		buffer2 = new float[BANDS][lbLong];
		_function = new float[lbLong*2];
		overlap = new float[BANDS][lbLong*2];
	}

	public void decode(IBitStream _in, WindowSequence winSeq) throws AACException {
		maxBand = _in.readBits(2)+1;

		int wdLen, locBits, locBits2 = 0;
		switch(winSeq) {
			case ONLY_LONG_SEQUENCE:
				wdLen = 1;
				locBits = 5;
				locBits2 = 5;
				break;
			case EIGHT_SHORT_SEQUENCE:
				wdLen = 8;
				locBits = 2;
				locBits2 = 2;
				break;
			case LONG_START_SEQUENCE:
				wdLen = 2;
				locBits = 4;
				locBits2 = 2;
				break;
			case LONG_STOP_SEQUENCE:
				wdLen = 2;
				locBits = 4;
				locBits2 = 5;
				break;
			default:
				return;
		}
		level = new int[maxBand][wdLen][];
		location = new int[maxBand][wdLen][];

		int wd, k, len, bits;
		for(int bd = 1; bd=loc[m[i]])&&(i<=loc[m[i]]+7)) fmd[i] = interpolateGain(lev[m[i]], lev[m[i]+1], i-loc[m[i]]);
			else fmd[i] = lev[m[i]+1];
		}

		return secLevel;
	}

	/**
	 * transformes the exponent value of the gain to the id of the gain change
	 * point
	 */
	private int getGainChangePointID(int lngain) {
		for(int i = 0; i