Android Open Source - voicesmith Pcm Out Device

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License

The source code is released under:
GNU General Public License
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Java Source Code

/*
 * Voicesmith <http://voicesmith.jurihock.de/>
 *//from   w w w  .ja va 2  s .  c  om
 * Copyright (c) 2011-2014 Juergen Hock
 *
 * 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 de.jurihock.voicesmith.io.pcm;

import java.io.IOException;
import java.util.Arrays;

import android.content.Context;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import de.jurihock.voicesmith.Preferences;
import de.jurihock.voicesmith.Utils;
import de.jurihock.voicesmith.audio.HeadsetMode;

public final class PcmOutDevice extends PcmDevice
{
    private static final int  WIRED_HEADPHONES_SOURCE    = AudioManager.STREAM_MUSIC;
  private static final int  WIRED_HEADSET_SOURCE    = AudioManager.STREAM_MUSIC;
  private static final int  BLUETOOTH_HEADSET_SOURCE  = AudioManager.STREAM_VOICE_CALL;

  private AudioTrack      output            = null;

  public PcmOutDevice(Context context, HeadsetMode headsetMode)
    throws IOException
  {
    super(context);

    switch (headsetMode)
    {
        case WIRED_HEADPHONES:
            setAudioSource(WIRED_HEADPHONES_SOURCE);
            break;
    case WIRED_HEADSET:
      setAudioSource(WIRED_HEADSET_SOURCE);
      break;
    case BLUETOOTH_HEADSET:
      setSampleRate(8000);
      new Utils(context).log("Sample rate changed to 8000 Hz.");
      setAudioSource(BLUETOOTH_HEADSET_SOURCE);
      break;
    default:
      throw new IOException("Unknown HeadsetMode!");
    }

    init(context);
  }

  public PcmOutDevice(Context context, int sampleRate) throws IOException
  {
    super(context, sampleRate);
    init(context);
  }

  public PcmOutDevice(Context context) throws IOException
  {
    super(context);
    init(context);
  }

  private void init(Context context) throws IOException
  {
    this.setChannels(AudioFormat.CHANNEL_OUT_MONO); // DON'T CHANGE!
    this.setEncoding(AudioFormat.ENCODING_PCM_16BIT); // DON'T CHANGE!
    this.setMinBufferSize(AudioTrack.getMinBufferSize(
      getSampleRate(), getChannels(), getEncoding()));

    if (this.getMinBufferSize() == AudioTrack.ERROR_BAD_VALUE ||
      this.getMinBufferSize() == AudioTrack.ERROR)
    {
      throw new IOException(
        "Unable to determine the MinBufferSize for AudioTrack!");
    }

    this.setBufferSize(new Preferences(context)
      .getPcmBufferSize(getSampleRate()));
    new Utils(context).log("PCM OUT buffer size is %s.", this.getBufferSize());

    output = new WrappedAudioTrack(getAudioSource(), getSampleRate(),
      getChannels(), getEncoding(), getBufferSize(),
      AudioTrack.MODE_STREAM);

    if (output.getState() != AudioTrack.STATE_INITIALIZED)
    {
      dispose();
      throw new IOException(
        "Unable to initialize an AudioTrack instance!");
    }
  }

  @Override
  public int write(short[] buffer, int offset, int count)
  {
        if (count == 0) return 0;

    return output.write(buffer, offset, count);
  }

  @Override
  public void flush()
  {
    output.flush();
  }

  @Override
  public void start()
  {
    output.play();

    // Stuff the internal PCM buffer with empty data
    final byte[] buffer = new byte[getBufferSize()];
    Arrays.fill(buffer, (byte)0);
    output.write(buffer, 0, buffer.length);
  }

  @Override
  public void stop()
  {
    output.stop();
  }

  @Override
  public void dispose()
  {
    if (output != null)
    {
      output.release();
      output = null;
    }
  }

  private final class WrappedAudioTrack extends AudioTrack
  {
    public WrappedAudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)
      throws IllegalArgumentException
    {
      super(streamType, sampleRateInHz, channelConfig, audioFormat,
        bufferSizeInBytes, mode);

      new Utils(context).log("PCM OUT native frame count is %s.",
        getNativeFrameCount());
    }
  }
}
Java Source Code List
