Android Open Source - android-fskmodem Wav To P C M

• Back to Sound/audio  ↑

From Project

Back to project page android-fskmodem.

License

The source code is released under:

GNU General Public License

Java Source Code

/**
 * I am not sure who is the author of the essential part of this file's code.
 * /*w w  w  .j  a  va 2  s .com*/
 * I found it on this blog post http://mindtherobot.com/blog/580/android-audio-play-a-wav-file-on-an-audiotrack/
 * 
 * I figured out the missing parts of the code for myself and completed the class to be usable...
 * 
 * If anyone feels offended by the use of this code, please contact me at iganev@cytec.bg
 * 
 * Regards to the author! :)
 */

package bg.cytec.android.wav;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

public class WavToPCM {
  public static final String RIFF_HEADER = "RIFF";
  public static final String WAVE_HEADER = "WAVE";
  public static final String FMT_HEADER = "fmt ";
  public static final String DATA_HEADER = "data";

  public static final int HEADER_SIZE = 44;

  public static final String CHARSET = "ASCII";

  protected static void checkFormat(boolean assertion, String message) throws IOException
  {
    if (!assertion)
    {
      throw new IOException(message);
    }
  }
  
  public static class WavInfo {
    int sampleRate;
    int bits;
    int dataSize;
    
    boolean isStereo;
    
    public WavInfo(int rate, int bits, boolean isStereo, int dataSize) {
      this.sampleRate = rate;
      this.bits = bits;
      this.isStereo = isStereo;
      this.dataSize = dataSize;
    }
    
    public int getSampleRate()
    {
      return sampleRate;
    }
    
    public int getBits()
    {
      return bits;
    }
    
    public int getDataSize()
    {
      return dataSize;
    }
    
    public boolean isStereo()
    {
      return isStereo;
    }
  }
  
  public static WavInfo readHeader(InputStream wavStream) throws IOException {

    ByteBuffer buffer = ByteBuffer.allocate(HEADER_SIZE);
    buffer.order(ByteOrder.LITTLE_ENDIAN);

    wavStream.read(buffer.array(), buffer.arrayOffset(), buffer.capacity());

    buffer.rewind();
    buffer.position(buffer.position() + 20);
    
    int format = buffer.getShort();
    
    checkFormat(format == 1, "Unsupported encoding: " + format); // 1 means
                                    // Linear
                                    // PCM
    int channels = buffer.getShort();
    
    checkFormat(channels == 1 || channels == 2, "Unsupported channels: "
        + channels);
    
    int rate = buffer.getInt();
    
    checkFormat(rate <= 48000 && rate >= 11025, "Unsupported rate: " + rate);
    
    buffer.position(buffer.position() + 6);
    
    int bits = buffer.getShort();
    //checkFormat(bits == 16, "Unsupported bits: " + bits);
    
    int dataSize = 0;
    
    while (buffer.getInt() != 0x61746164) { // "data" marker
      int size = buffer.getInt();
      wavStream.skip(size);

      buffer.rewind();
      wavStream.read(buffer.array(), buffer.arrayOffset(), 8);
      buffer.rewind();
    }
    
    dataSize = buffer.getInt();
    
    checkFormat(dataSize > 0, "wrong datasize: " + dataSize);

    return new WavInfo(rate, bits, channels == 2, dataSize);
  }

  public static byte[] readWavPcm(WavInfo info, InputStream stream) throws IOException {
    
    byte[] data = new byte[info.getDataSize()];
    stream.read(data, 0, data.length);
    
    return data;
  }
  
  public static byte[] readWavPcm(InputStream stream) throws IOException {
    
    WavInfo info = readHeader(stream);
    
    return readWavPcm(info, stream);
  }
}

Java Source Code List

• Back to Sound/audio  ↑