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295 lines
8.9 KiB
295 lines
8.9 KiB
//
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// File : adpcmcodec.cpp
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// Creation date : Wed Aug 22 19:12:50 2001 GMT by Szymon Stefanek
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//
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// This file is part of the KVirc irc client distribution
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//
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// Code derived from adpcm.c : Intel ADPCM coder/decoder
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// Adapted for the KVirc distribution by Szymon Stefanek (pragma at kvirc dot net)
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// Last revision : 20 Sep 1999
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//
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// Copyright 1992 by Stichting Mathematisch Centrum, Amsterdam, The Netherlands.
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// All Rights Reserved
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//
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// Permission to use, copy, modify, and distribute this software and its
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// documentation for any purpose and without fee is hereby granted,
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// provided that the above copyright notice appear in all copies and that
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// both that copyright notice and this permission notice appear in
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// supporting documentation, and that the names of Stichting Mathematisch
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// Centrum or CWI not be used in advertising or publicity pertaining to
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// distribution of the software without specific, written prior permission.
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//
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// STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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// THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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// FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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// OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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//
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//
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// Intel/DVI ADPCM coder/decoder.
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//
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// The algorithm for this coder was taken from the IMA Compatability Project
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// proceedings, Vol 2, Number 2; May 1992.
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//
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// Version 1.2, 18-Dec-92.
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//
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#define _ADPCMCODEC_CPP_
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#include "adpcmcodec.h"
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#include <stdio.h> /*DBG*/
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#ifndef __STDC__
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#define signed
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#endif
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#define ADPCM_PACKED_FRAME_SIZE_IN_BYTES 512
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#define ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES 2048
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#define ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS 1024
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// Intel ADPCM step variation table */
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static int indexTable[16] = {
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-1, -1, -1, -1, 2, 4, 6, 8,
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-1, -1, -1, -1, 2, 4, 6, 8,
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};
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static int stepsizeTable[89] = {
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7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
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19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
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50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
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130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
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337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
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876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
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2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
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5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
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15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
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};
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void ADPCM_compress(short indata[],char outdata[],int len,ADPCM_state *state)
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{
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short *lpIn; /* Input buffer pointer */
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signed char *lpOut; /* output buffer pointer */
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int val; /* Current input sample value */
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int sign; /* Current adpcm sign bit */
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int delta; /* Current adpcm output value */
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int diff; /* Difference between val and valprev */
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int step; /* Stepsize */
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int valpred; /* Predicted output value */
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int vpdiff; /* Current change to valpred */
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int index; /* Current step change index */
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int outputbuffer = 0; /* place to keep previous 4-bit value */
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int bufferstep; /* toggle between outputbuffer/output */
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lpOut = (signed char *)outdata;
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lpIn = indata;
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valpred = state->valprev;
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index = state->index;
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step = stepsizeTable[index];
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bufferstep = 1;
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for ( ;len > 0;len-- ) {
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val = *lpIn++;
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// Step 1 - compute difference with previous value
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diff = val - valpred;
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sign = (diff < 0) ? 8 : 0;
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if(sign)diff=(-diff);
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// Step 2 - Divide and clamp
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// Note:
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// This code *approximately* computes:
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// delta = diff*4/step;
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// vpdiff = (delta+0.5)*step/4;
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// but in shift step bits are dropped. The net result of this is
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// that even if you have fast mul/div hardware you cannot put it to
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// good use since the fixup would be too expensive.
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//
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delta = 0;
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vpdiff = (step >> 3);
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if (diff >=step){
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delta = 4;
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diff -= step;
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vpdiff += step;
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}
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step >>= 1;
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if (diff >= step) {
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delta |= 2;
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diff -= step;
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vpdiff += step;
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}
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step >>= 1;
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if ( diff >= step ) {
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delta |= 1;
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vpdiff += step;
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}
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// Step 3 - Update previous value
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if(sign)valpred -= vpdiff;
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else valpred += vpdiff;
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// Step 4 - Clamp previous value to 16 bits
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if ( valpred > 32767 )valpred = 32767;
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else if ( valpred < -32768 )valpred = -32768;
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// Step 5 - Assemble value, update index and step values
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delta |= sign;
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index += indexTable[delta];
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if ( index < 0 ) index = 0;
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if ( index > 88 ) index = 88;
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step = stepsizeTable[index];
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// Step 6 - Output value
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if ( bufferstep )outputbuffer = (delta << 4) & 0xf0;
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else *lpOut++ = (delta & 0x0f) | outputbuffer;
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bufferstep = !bufferstep;
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}
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// Output last step, if needed
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if (!bufferstep)*lpOut++ = outputbuffer;
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state->valprev = valpred;
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state->index = index;
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}
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void ADPCM_uncompress(char indata[],short outdata[],int len,ADPCM_state *state)
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{
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signed char *inp; /* Input buffer pointer */
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short *outp; /* output buffer pointer */
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int sign; /* Current adpcm sign bit */
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int delta; /* Current adpcm output value */
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int step; /* Stepsize */
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int valpred; /* Predicted value */
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int vpdiff; /* Current change to valpred */
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int index; /* Current step change index */
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int inputbuffer=0; /* place to keep next 4-bit value */
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int bufferstep; /* toggle between inputbuffer/input */
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outp = outdata;
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inp = (signed char *)indata;
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valpred = state->valprev;
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index = state->index;
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step = stepsizeTable[index];
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bufferstep = 0;
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for ( ; len > 0 ; len-- ) {
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/* Step 1 - get the delta value */
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if ( bufferstep )delta = inputbuffer & 0xf;
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else {
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inputbuffer = *inp++;
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delta = (inputbuffer >> 4) & 0xf;
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}
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bufferstep = !bufferstep;
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/* Step 2 - Find new index value (for later) */
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index += indexTable[delta];
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if ( index < 0 ) index = 0;
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if ( index > 88 ) index = 88;
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/* Step 3 - Separate sign and magnitude */
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sign = delta & 8;
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delta = delta & 7;
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/* Step 4 - Compute difference and new predicted value */
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/*
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** Computes 'vpdiff = (delta+0.5)*step/4', but see comment
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** in adpcm_coder.
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*/
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vpdiff = step >> 3;
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if( delta & 4 )vpdiff += step;
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if( delta & 2 )vpdiff += step>>1;
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if( delta & 1 )vpdiff += step>>2;
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if(sign)valpred -= vpdiff;
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else valpred += vpdiff;
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/* Step 5 - clamp output value */
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if(valpred > 32767)valpred = 32767;
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else if(valpred < -32768)valpred = -32768;
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/* Step 6 - Update step value */
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step = stepsizeTable[index];
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/* Step 7 - Output value */
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*outp++ = valpred;
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}
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state->valprev = valpred;
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state->index = index;
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}
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KviDccVoiceAdpcmCodec::KviDccVoiceAdpcmCodec()
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: KviDccVoiceCodec()
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{
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m_pEncodeState = new ADPCM_state;
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m_pEncodeState->index = 0;
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m_pEncodeState->valprev = 0;
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m_pDecodeState = new ADPCM_state;
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m_pDecodeState->index = 0;
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m_pDecodeState->valprev = 0;
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m_szName = "adpcm (compression 1:4)";
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}
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KviDccVoiceAdpcmCodec::~KviDccVoiceAdpcmCodec()
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{
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delete m_pEncodeState;
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delete m_pDecodeState;
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}
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void KviDccVoiceAdpcmCodec::encode(KviDataBuffer * signal,KviDataBuffer * stream)
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{
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if(signal->size() < ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES)return; // nothing to encode
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char * ptr = (char *)signal->data();
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int uFrames = signal->size() / ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
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int uTotalDataCompressed = uFrames * ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
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int uFrameOffset = stream->size();
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char * endPtr = ptr + uTotalDataCompressed;
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stream->addSize(ADPCM_PACKED_FRAME_SIZE_IN_BYTES * uFrames);
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while(ptr != endPtr)
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{
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ADPCM_compress((short *)ptr,(char *)(stream->data() + uFrameOffset),ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS,m_pEncodeState);
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ptr += ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
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uFrameOffset += ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
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}
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signal->remove(uTotalDataCompressed);
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}
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void KviDccVoiceAdpcmCodec::decode(KviDataBuffer * stream,KviDataBuffer * signal)
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{
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if(stream->size() < ADPCM_PACKED_FRAME_SIZE_IN_BYTES)return; // nothing to decode
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char * ptr = (char *)stream->data();
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// Adpcm codec
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int uFrames = stream->size() / ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
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int uTotalDataDecompressed = uFrames * ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
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int uSignalOffset = signal->size();
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char * endPtr = ptr + (uTotalDataDecompressed);
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signal->addSize(ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES * uFrames);
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while(ptr != endPtr)
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{
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ADPCM_uncompress((char *)ptr,(short *)(signal->data() + uSignalOffset),ADPCM_UNPACKED_FRAME_SIZE_IN_SHORTS,m_pDecodeState);
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ptr += ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
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uSignalOffset += ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
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}
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stream->remove(uTotalDataDecompressed);
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}
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int KviDccVoiceAdpcmCodec::encodedFrameSize()
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{
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return ADPCM_PACKED_FRAME_SIZE_IN_BYTES;
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}
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int KviDccVoiceAdpcmCodec::decodedFrameSize()
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{
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return ADPCM_UNPACKED_FRAME_SIZE_IN_BYTES;
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}
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