Encoder.java

package org.mobicents.media.server.impl.dsp.audio.gsm;

import org.mobicents.media.Buffer;
import org.mobicents.media.Format;
import org.mobicents.media.server.spi.dsp.Codec;
import org.mobicents.media.server.spi.dsp.SignalingProcessor;

/**
 * 
 * @author amit bhayani
 * 
 */
public class Encoder implements Codec {

	private org.tritonus.lowlevel.gsm.Encoder encoder = new org.tritonus.lowlevel.gsm.Encoder();

	private short[] signal = new short[160];
	private byte[] res = new byte[33];

	public void process(Buffer buffer) {
		if (buffer.getLength() != 320) {
			buffer.setFlags(Buffer.FLAG_BUF_UNDERFLOWN);
			return;
		}

		// encode into short values
		byte[] data = (byte[]) buffer.getData();

		// int k = 0;
		for (int i = 0; i < 160; i++) {
			// signal[i] = (short) ((data[k++] << 8) & (data[k++]));
			signal[i] = bytesToShort16(data, i * 2, false);
		}

		encoder.encode(signal, res);
		int length = res.length;
		
		System.arraycopy(res, 0, (byte[])buffer.getData(), 0, length);

		//buffer.setData(res);
		buffer.setOffset(0);
		buffer.setFormat(Codec.GSM);
		buffer.setLength(length);
	}

	private short bytesToShort16(byte[] buffer, int byteOffset, boolean bigEndian) {
		return bigEndian ? ((short) ((buffer[byteOffset] << 8) | (buffer[byteOffset + 1] & 0xFF)))
				: ((short) ((buffer[byteOffset + 1] << 8) | (buffer[byteOffset] & 0xFF)));
	}

	public Format getSupportedInputFormat() {
		return Codec.LINEAR_AUDIO;
	}

	public Format getSupportedOutputFormat() {
		return Codec.GSM;
	}

	public void setProc(SignalingProcessor processor) {
		// TODO Auto-generated method stub

	}

}