Subframe_Constant.java

/*
 * Copyright (C) 2010  Preston Lacey http://javaflacencoder.sourceforge.net/
 * All Rights Reserved.
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package javaFlacEncoder;

/**
 * Implements the Subframe abstract class, providing encoding support for the
 * FLAC Constant Subframe.
 *
 * @author Preston Lacey
 */
public class Subframe_Constant extends Subframe {
    /** For debugging: Higher values equals greater output, generally by
     * increments of 10. */
    public static int DEBUG_LEV = 0;
    /** Subframe type supported by this implementation. */
    public static final EncodingConfiguration.SubframeType type =
            EncodingConfiguration.SubframeType.VERBATIM;
    int sampleSize = 0;

    /**
     * Constructor. Sets StreamConfiguration to use. If the StreamConfiguration
     * must later be changed, a new Subframe object must be created as well.
     *
     * @param sc StreamConfiguration to use for encoding.
     */
    public Subframe_Constant(StreamConfiguration sc) {
        super(sc);
        sampleSize = sc.getBitsPerSample();
    }

    /**
     * This method is used to set the encoding configuration.
     * @param ec    encoding configuration to use.
     * @return      true if configuration was changed, false otherwise
     */
    @Override
    public boolean registerConfiguration(EncodingConfiguration ec) {
        super.registerConfiguration(ec);

        return true;
    }

    
    public int encodeSamples(int[] samples, int count, int start, int skip,
        EncodedElement data, int offset, int bitsPerSample ) {
        if(DEBUG_LEV > 0) {
            System.err.println("Subframe_Verbatim::encodeSamples(...)");
        }
        int encodedSamples = count;
        int bits = bitsPerSample+offset+8;
        int bytesNeeded = bits/8;
        if(bits%8 != 0)
            bytesNeeded++;
        data.clear(bytesNeeded, offset);
        data.addInt(0,1);
        data.addInt(0,6);
        data.addInt(0,1);

        int value = samples[start];
        int increment = skip+1;
        int end = start+increment*count;
        int lastValid = end-increment;//assume all were the same
        for(int i = start; i < end; i+= increment) {
           if(samples[i] != value) {
              lastValid = i-increment;//if one differed, find where
              break;
           }
        }
        encodedSamples = (lastValid-start)/increment+1;
        data.addInt(value,bitsPerSample);
        lastEncodedSize = bits - offset;
        System.out.flush();
        if(DEBUG_LEV > 0)
            System.err.println("Subframe_Verbatim::encodeSamples(...): End");
        if(DEBUG_LEV > 10) {
            System.err.println("--: bitsUsed : "+bits+"  : Bytes : "+bytesNeeded);
        }
        return encodedSamples;
    }

}