JavaEncoder.java

/*
 * @(#)JavaEncoder.java	1.4 02/08/21
 *
 * Copyright (c) 1996-2002 Sun Microsystems, Inc.  All rights reserved.
 */

package com.ibm.media.codec.audio.ulaw;

import javax.media.*;
import javax.media.format.*;
import javax.media.format.*;
import com.sun.media.*;


public class JavaEncoder extends com.ibm.media.codec.audio.AudioCodec {

  private Format lastFormat=null;
  private int numberOfInputChannels;
  private int numberOfOutputChannels=1;
  private boolean downmix=false;
  private int inputSampleSize;
  private int lsbOffset;
  private int msbOffset;
  private int inputBias;
  private int signMask;


 public JavaEncoder() {
        supportedInputFormats = new AudioFormat[] {
                new AudioFormat(
                AudioFormat.LINEAR,
                Format.NOT_SPECIFIED,
                16,
                1,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                ),
                new AudioFormat(
                AudioFormat.LINEAR,
                Format.NOT_SPECIFIED,
                16,
                2,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                ),
                new AudioFormat(
                AudioFormat.LINEAR,
                Format.NOT_SPECIFIED,
                8,
                1,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                ),
                new AudioFormat(
                AudioFormat.LINEAR,
                Format.NOT_SPECIFIED,
                8,
                2,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                )	};  // support 1/2 channels and 8/16 bit samples

        defaultOutputFormats  =  new AudioFormat[] {
                new AudioFormat(
                AudioFormat.ULAW,
                8000,
                8,
                1,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                )                };
        PLUGIN_NAME="pcm to mu-law converter";
 }


  protected  Format[] getMatchingOutputFormats(Format in) {


       AudioFormat inFormat=(AudioFormat)in;
       int channels = inFormat.getChannels();
       int sampleRate = (int) (inFormat.getSampleRate());


       if (channels==2) {
        supportedOutputFormats = new AudioFormat[] {
                new AudioFormat(
                AudioFormat.ULAW,
                sampleRate,
                8,
                2,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                ),
		new AudioFormat(
                AudioFormat.ULAW,
                sampleRate,
                8,
                1,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                )                };

       }
       else {
        supportedOutputFormats = new AudioFormat[] {
                new AudioFormat(
                AudioFormat.ULAW,
                sampleRate,
                8,
                1,
                Format.NOT_SPECIFIED,
                Format.NOT_SPECIFIED
                )                };

       }


        return  supportedOutputFormats;
  }


  public void open() throws ResourceUnavailableException {
  }

  public void close() {

  }


  public int process(Buffer inputBuffer, Buffer outputBuffer) {
    if (!checkInputBuffer(inputBuffer) ) {
            return BUFFER_PROCESSED_FAILED;
    }

    if (isEOM(inputBuffer) ) {
            propagateEOM(outputBuffer);
            return BUFFER_PROCESSED_OK;
    }

    Format newFormat = inputBuffer.getFormat();

    if (lastFormat != newFormat) {
        initConverter((AudioFormat)newFormat);
    }

    int inpLength=inputBuffer.getLength();
    int outLength = calculateOutputSize(inputBuffer.getLength() );

    byte[] inpData = (byte[]) inputBuffer.getData();
    byte[] outData = validateByteArraySize(outputBuffer, outLength);

    convert(inpData, inputBuffer.getOffset(),inpLength, outData, 0);

    updateOutput(outputBuffer, outputFormat, outLength, 0);
    return BUFFER_PROCESSED_OK;

  }


  private int calculateOutputSize(int inputLength) {
    if (inputSampleSize == 16) {
      inputLength/=2;
    }

    if (downmix) {
      inputLength/=2;
    }

    return inputLength;
  }

  private void initConverter(AudioFormat inFormat) {

     lastFormat=inFormat;
     numberOfInputChannels=inFormat.getChannels();
     if (outputFormat != null)
       numberOfOutputChannels=outputFormat.getChannels();
     inputSampleSize=inFormat.getSampleSizeInBits();




     if ( (inFormat.getEndian()==AudioFormat.BIG_ENDIAN) || (8 == inputSampleSize) ) {
       lsbOffset = 1;
       msbOffset=0;
     }
     else {
       lsbOffset = -1;
       msbOffset=1;
     }

     if (inFormat.getSigned()==AudioFormat.SIGNED) {
       inputBias = 0;
       signMask=0xffffffff;
     }
     else {
        inputBias = 32768;
    	signMask=0x0000ffff;
     }

     if ( (numberOfInputChannels==2) && (numberOfOutputChannels==1)  ) {
        downmix=true;
     }
     else {
        downmix=false;
     }

  }

  private void convert(byte[] input,int inputOffset,int inputLength,byte[] outData,int outputOffset) {

      int sample, signBit , inputSample;
      int i;

      for(i=inputOffset+msbOffset;i<(inputLength+inputOffset); ) {


      if (8 == inputSampleSize) {
           inputSample = input[i++]<<8;

            if (downmix) {
                 inputSample = ( (inputSample&signMask) + ( (input[i++]<<8)&signMask) ) >> 1;
           }
      }
      else {
          inputSample  = (input[i] << 8) + (0xff & input[i+lsbOffset]);
          i+=2;

           if (downmix) {
                 inputSample = ( (inputSample&signMask)+ ( ((input[i] << 8) + (0xff & input[i+lsbOffset]))&signMask ) )>>1;
                 i+=2;
           }
      }


      sample = (int)( (short)(inputSample+inputBias) );


      if (sample>=0) {    // Sample=abs(sample)
          signBit=0x80;   // sign bit
       } else {
          sample= -sample;
          signBit=0x00;
       }

       sample = (132 + sample) >> 3; //bias

       outData[outputOffset++]=(byte)((sample<0x0020) ? (signBit | (7 << 4) | (31 - (sample >> 0) )) :
                                      (sample<0x0040) ? (signBit | (6 << 4) | (31 - (sample >> 1) )) :
                                      (sample<0x0080) ? (signBit | (5 << 4) | (31 - (sample >> 2) )) :
                                      (sample<0x0100) ? (signBit | (4 << 4) | (31 - (sample >> 3) )) :
                                      (sample<0x0200) ? (signBit | (3 << 4) | (31 - (sample >> 4) )) :
                                      (sample<0x0400) ? (signBit | (2 << 4) | (31 - (sample >> 5) )) :
                                      (sample<0x0800) ? (signBit | (1 << 4) | (31 - (sample >> 6) )) :
                                      (sample<0x1000) ? (signBit | (0 << 4) | (31 - (sample >> 7) )) :
                                      (signBit | (0 << 4) | (31 - (0xfff  >> 7) )) );
         }

  }


}