path: root/src/modules/dcc/adpcmcodec.cpp

//
//   File : adpcmcodec.cpp
//   Creation date : Wed Aug 22 19:12:50 2001 GMT by Szymon Stefanek
//
//   This file is part of the KVirc irc client distribution
//
//   Code derived from adpcm.c : Intel ADPCM coder/decoder
//   Adapted for the KVirc distribution by Szymon Stefanek (pragma at kvirc dot net)
//   Last revision : 20 Sep 1999
//
// Copyright 1992 by Stichting Mathematisch Centrum, Amsterdam, The Netherlands.
//                           All Rights Reserved
//
// Permission to use, copy, modify, and distribute this software and its 
// documentation for any purpose and without fee is hereby granted, 
// provided that the above copyright notice appear in all copies and that
// both that copyright notice and this permission notice appear in 
// supporting documentation, and that the names of Stichting Mathematisch
// Centrum or CWI not be used in advertising or publicity pertaining to
// distribution of the software without specific, written prior permission.
//
// STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
// THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
// FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
// OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
//
// Intel/DVI ADPCM coder/decoder.
//
// The algorithm for this coder was taken from the IMA Compatability Project
// proceedings, Vol 2, Number 2; May 1992.
//
// Version 1.2, 18-Dec-92.
//

#define _ADPCMCODEC_CPP_
#include "adpcmcodec.h"

#include <stdio.h> /*DBG*/

#ifndef __STDC__
	#define signed
#endif



#define ADPCM_PACKED_FRAME_SIZE_IN_BYTES 512
#define ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES 2048
#define ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS 1024

// Intel ADPCM step variation table */
static int indexTable[16] = {
    -1, -1, -1, -1, 2, 4, 6, 8,
    -1, -1, -1, -1, 2, 4, 6, 8,
};

static int stepsizeTable[89] = {
    7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
    19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
    50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
    130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
    337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
    876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
    2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
    5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
    15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};


void ADPCM_compress(short indata[],char outdata[],int len,ADPCM_state *state)
{
    short *lpIn;          /* Input buffer pointer */
    signed char *lpOut;   /* output buffer pointer */
    int val;              /* Current input sample value */
    int sign;             /* Current adpcm sign bit */
    int delta;            /* Current adpcm output value */
    int diff;             /* Difference between val and valprev */
    int step;             /* Stepsize */
    int valpred;          /* Predicted output value */
    int vpdiff;           /* Current change to valpred */
    int index;            /* Current step change index */
    int outputbuffer = 0; /* place to keep previous 4-bit value */
    int bufferstep;	      /* toggle between outputbuffer/output */

    lpOut = (signed char *)outdata;
    lpIn  = indata;

    valpred = state->valprev;
    index = state->index;
    step = stepsizeTable[index];
    
    bufferstep = 1;

    for ( ;len > 0;len-- ) {
		val = *lpIn++;
		// Step 1 - compute difference with previous value
		diff = val - valpred;
		sign = (diff < 0) ? 8 : 0;
		if(sign)diff=(-diff);
		// Step 2 - Divide and clamp 
		// Note:
		// This code *approximately* computes:
		//    delta = diff*4/step;
		//    vpdiff = (delta+0.5)*step/4;
		// but in shift step bits are dropped. The net result of this is
		// that even if you have fast mul/div hardware you cannot put it to
		// good use since the fixup would be too expensive.
		//
		delta = 0;
		vpdiff = (step >> 3);
		if (diff >=step){
		    delta = 4;
		    diff -= step;
		    vpdiff += step;
		}
		step >>= 1;
		if (diff >= step) {
		    delta |= 2;
		    diff -= step;
		    vpdiff += step;
		}
		step >>= 1;
		if ( diff >= step ) {
		    delta |= 1;
		    vpdiff += step;
		}
		// Step 3 - Update previous value
		if(sign)valpred -= vpdiff;
		else valpred += vpdiff;
		// Step 4 - Clamp previous value to 16 bits
		if ( valpred > 32767 )valpred = 32767;
		else if ( valpred < -32768 )valpred = -32768;
		// Step 5 - Assemble value, update index and step values
		delta |= sign;	
		index += indexTable[delta];
		if ( index < 0 ) index = 0;
		if ( index > 88 ) index = 88;
		step = stepsizeTable[index];
		// Step 6 - Output value
		if ( bufferstep )outputbuffer = (delta << 4) & 0xf0;
		else *lpOut++ = (delta & 0x0f) | outputbuffer;
		bufferstep = !bufferstep;
    }
    // Output last step, if needed
    if (!bufferstep)*lpOut++ = outputbuffer;
    state->valprev = valpred;
    state->index = index;
}

void ADPCM_uncompress(char indata[],short outdata[],int len,ADPCM_state *state)
{
    signed char *inp;		/* Input buffer pointer */
    short *outp;		/* output buffer pointer */
    int sign;			/* Current adpcm sign bit */
    int delta;			/* Current adpcm output value */
    int step;			/* Stepsize */
    int valpred;		/* Predicted value */
    int vpdiff;			/* Current change to valpred */
    int index;			/* Current step change index */
    int inputbuffer=0;  /* place to keep next 4-bit value */
    int bufferstep;		/* toggle between inputbuffer/input */

    outp = outdata;
    inp = (signed char *)indata;

    valpred = state->valprev;
    index = state->index;
    step = stepsizeTable[index];

    bufferstep = 0;
    
    for ( ; len > 0 ; len-- ) {
	
		/* Step 1 - get the delta value */
		if ( bufferstep )delta = inputbuffer & 0xf;
		else {
			inputbuffer = *inp++;
			delta = (inputbuffer >> 4) & 0xf;
		}
		bufferstep = !bufferstep;

		/* Step 2 - Find new index value (for later) */
		index += indexTable[delta];
		if ( index < 0 ) index = 0;
		if ( index > 88 ) index = 88;

		/* Step 3 - Separate sign and magnitude */
		sign = delta & 8;
		delta = delta & 7;

		/* Step 4 - Compute difference and new predicted value */
		/*
		** Computes 'vpdiff = (delta+0.5)*step/4', but see comment
		** in adpcm_coder.
		*/
		vpdiff = step >> 3;
		if( delta & 4 )vpdiff += step;
		if( delta & 2 )vpdiff += step>>1;
		if( delta & 1 )vpdiff += step>>2;

		if(sign)valpred -= vpdiff;
		else valpred += vpdiff;

		/* Step 5 - clamp output value */
		if(valpred > 32767)valpred = 32767;
		else if(valpred < -32768)valpred = -32768;

		/* Step 6 - Update step value */
		step = stepsizeTable[index];

		/* Step 7 - Output value */
		*outp++ = valpred;
    }

    state->valprev = valpred;
    state->index = index;
}


KviDccVoiceAdpcmCodec::KviDccVoiceAdpcmCodec()
: KviDccVoiceCodec()
{
	m_pEncodeState = new ADPCM_state;
	m_pEncodeState->index = 0;
	m_pEncodeState->valprev = 0;
	m_pDecodeState = new ADPCM_state;
	m_pDecodeState->index = 0;
	m_pDecodeState->valprev = 0;
	m_szName = "adpcm (compression 1:4)";
}

KviDccVoiceAdpcmCodec::~KviDccVoiceAdpcmCodec()
{
	delete m_pEncodeState;
	delete m_pDecodeState;
}

void KviDccVoiceAdpcmCodec::encode(KviDataBuffer * signal,KviDataBuffer * stream)
{
	if(signal->size() < ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES)return; // nothing to encode

	char * ptr = (char *)signal->data();

	int uFrames = signal->size() / ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
	int uTotalDataCompressed = uFrames * ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
	int uFrameOffset = stream->size();
	char * endPtr = ptr + uTotalDataCompressed;

	stream->addSize(ADPCM_PACKED_FRAME_SIZE_IN_BYTES * uFrames);

	while(ptr != endPtr)
	{
		ADPCM_compress((short *)ptr,(char *)(stream->data() + uFrameOffset),ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS,m_pEncodeState);
		ptr += ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
		uFrameOffset += ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
	}
	signal->remove(uTotalDataCompressed);
}

void KviDccVoiceAdpcmCodec::decode(KviDataBuffer * stream,KviDataBuffer * signal)
{
	if(stream->size() < ADPCM_PACKED_FRAME_SIZE_IN_BYTES)return; // nothing to decode

	char * ptr = (char *)stream->data();

	// Adpcm codec
	int uFrames = stream->size() / ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
	int uTotalDataDecompressed = uFrames * ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
	int uSignalOffset = signal->size();
	char * endPtr = ptr + (uTotalDataDecompressed);

	signal->addSize(ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES * uFrames);

	while(ptr != endPtr)
	{
		ADPCM_uncompress((char *)ptr,(short *)(signal->data() + uSignalOffset),ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS,m_pDecodeState);
		ptr += ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
		uSignalOffset += ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
	}
	stream->remove(uTotalDataDecompressed);
}

int KviDccVoiceAdpcmCodec::encodedFrameSize()
{
	return ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
}

int KviDccVoiceAdpcmCodec::decodedFrameSize()
{
	return ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
}