sdrtrunk/src/audio/AudioUtils.java

/*******************************************************************************
 * sdrtrunk
 * Copyright (C) 2014-2016 Dennis Sheirer
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 ******************************************************************************/
package audio;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import record.wave.RealBufferWaveRecorder;
import sample.ConversionUtils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;

public class AudioUtils
{
    private final static Logger mLog = LoggerFactory.getLogger(AudioUtils.class);

    /**
     * Converts the audio packets into a byte array of 16-bit, little-endian audio samples
     */
    public static byte[] convertTo16BitSamples(List<AudioPacket> audioPackets)
    {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();

        try
        {
            for(AudioPacket packet: audioPackets)
            {
                //Converting from 32-bit floats to signed 16-bit samples
                ByteBuffer buffer = ConversionUtils.convertToSigned16BitSamples(packet.getAudioBuffer().getSamples());
                stream.write(buffer.array());
            }
        }
        catch(IOException e)
        {
            mLog.error("Error writing converted PCM bytes to output stream");
        }

        return stream.toByteArray();
    }
}