mirror of
https://github.com/DSheirer/sdrtrunk.git
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97 lines
3.3 KiB
Java
97 lines
3.3 KiB
Java
/*******************************************************************************
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* sdrtrunk
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* Copyright (C) 2014-2016 Dennis Sheirer
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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******************************************************************************/
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package io.github.dsheirer.audio.convert;
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import io.github.dsheirer.audio.AudioFormats;
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import io.github.dsheirer.audio.AudioUtils;
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import io.github.dsheirer.sample.buffer.ReusableAudioPacket;
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import net.sourceforge.lame.lowlevel.LameEncoder;
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import net.sourceforge.lame.mp3.Lame;
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import net.sourceforge.lame.mp3.MPEGMode;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import java.io.ByteArrayOutputStream;
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import java.util.Arrays;
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import java.util.List;
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public class MP3AudioConverter implements IAudioConverter
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{
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private final static Logger mLog = LoggerFactory.getLogger( MP3AudioConverter.class );
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public static final int AUDIO_QUALITY = Lame.QUALITY_LOW;
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private LameEncoder mEncoder;
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private ByteArrayOutputStream mMP3Stream = new ByteArrayOutputStream();
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private byte[] mMP3Buffer;
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/**
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* Converts PCM 8kHz 16-bit Little Endian audio packets to Mono, Low Quality MP3 compressed audio.
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*
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* @param bitRate for converted MP3 audio
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* @param variableBitRate (VBR) true or false for constant bit rate (CBR)
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*/
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public MP3AudioConverter(int bitRate, boolean variableBitRate)
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{
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mEncoder = new LameEncoder(AudioFormats.PCM_SIGNED_8KHZ_16BITS_MONO,
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bitRate, MPEGMode.MONO, AUDIO_QUALITY, variableBitRate);
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mMP3Buffer = new byte[mEncoder.getPCMBufferSize()];
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}
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@Override
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public byte[] convert(List<ReusableAudioPacket> audioPackets)
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{
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mMP3Stream.reset();
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byte[] pcmBytes = AudioUtils.convertTo16BitSamples(audioPackets);
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int pcmBufferSize = Math.min(mMP3Buffer.length, pcmBytes.length);
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int mp3BufferSize = 0;
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int pcmBytesPosition = 0;
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try
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{
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while (0 < (mp3BufferSize = mEncoder.encodeBuffer(pcmBytes, pcmBytesPosition, pcmBufferSize, mMP3Buffer)))
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{
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pcmBytesPosition += pcmBufferSize;
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pcmBufferSize = Math.min(mMP3Buffer.length, pcmBytes.length - pcmBytesPosition);
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mMP3Stream.write(mMP3Buffer, 0, mp3BufferSize);
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}
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return mMP3Stream.toByteArray();
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}
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catch(Exception e)
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{
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mLog.error("There was an error converting audio to MP3: " + e.getMessage());
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return new byte[0];
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}
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}
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@Override
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public byte[] flush()
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{
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byte[] lastPartialFrame = new byte[mEncoder.getMP3BufferSize()];
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int length = mEncoder.encodeFinish(lastPartialFrame);
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return Arrays.copyOf(lastPartialFrame, length);
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}
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}
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