QuantMatrixExtension.java

package org.jcodec.codecs.mpeg12.bitstream;

import java.io.IOException;

import org.jcodec.common.io.BitReader;
import org.jcodec.common.io.BitWriter;

/**
 * This class is part of JCodec ( www.jcodec.org ) This software is distributed
 * under FreeBSD License
 * 
 * @author The JCodec project
 * 
 */
public class QuantMatrixExtension {

    public int[] intra_quantiser_matrix;
    public int[] non_intra_quantiser_matrix;
    public int[] chroma_intra_quantiser_matrix;
    public int[] chroma_non_intra_quantiser_matrix;

    public static QuantMatrixExtension read(BitReader in) {
        QuantMatrixExtension qme = new QuantMatrixExtension();
        if (in.read1Bit() != 0)
            qme.intra_quantiser_matrix = readQMat(in);
        if (in.read1Bit() != 0)
            qme.non_intra_quantiser_matrix = readQMat(in);
        if (in.read1Bit() != 0)
            qme.chroma_intra_quantiser_matrix = readQMat(in);
        if (in.read1Bit() != 0)
            qme.chroma_non_intra_quantiser_matrix = readQMat(in);

        return qme;
    }

    private static int[] readQMat(BitReader in) {
        int[] qmat = new int[64];
        for (int i = 0; i < 64; i++)
            qmat[i] = in.readNBit(8);
        return qmat;
    }

    public void write(BitWriter ob) throws IOException {
        ob.write1Bit(intra_quantiser_matrix != null ? 1 : 0);
        if (intra_quantiser_matrix != null)
            writeQMat(intra_quantiser_matrix, ob);
        ob.write1Bit(non_intra_quantiser_matrix != null ? 1 : 0);
        if (non_intra_quantiser_matrix != null)
            writeQMat(non_intra_quantiser_matrix, ob);
        ob.write1Bit(chroma_intra_quantiser_matrix != null ? 1 : 0);
        if (chroma_intra_quantiser_matrix != null)
            writeQMat(chroma_intra_quantiser_matrix, ob);
        ob.write1Bit(chroma_non_intra_quantiser_matrix != null ? 1 : 0);
        if (chroma_non_intra_quantiser_matrix != null)
            writeQMat(chroma_non_intra_quantiser_matrix, ob);
    }

    private void writeQMat(int[] matrix, BitWriter ob) throws IOException {
        for (int i = 0; i < 64; i++)
            ob.writeNBit(matrix[i], 8);
    }
}