Added conversions to/from ADPCM(-4); renamed adpcm to adpcm3 (what it
really was).
This commit is contained in:
Guido van Rossum
parent
d7297e61df
commit
b64e63545f
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@ -130,9 +130,27 @@ int sample;
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}
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/* End of code taken from sox */
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/* ADPCM step variation table */
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/* ADPCM-3 step variation table */
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static float newstep[5] = { 0.8, 0.9, 1.0, 1.75, 1.75 };
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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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#define CHARP(cp, i) ((signed char *)(cp+i))
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#define SHORTP(cp, i) ((short *)(cp+i))
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#define LONGP(cp, i) ((long *)(cp+i))
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@ -550,7 +568,7 @@ audioop_ulaw2lin(self, args)
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}
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static object *
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audioop_lin2adpcm(self, args)
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audioop_lin2adpcm3(self, args)
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object *self;
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object *args;
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{
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@ -619,7 +637,7 @@ audioop_lin2adpcm(self, args)
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}
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static object *
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audioop_adpcm2lin(self, args)
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audioop_adpcm32lin(self, args)
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object *self;
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object *args;
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{
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@ -679,6 +697,175 @@ audioop_adpcm2lin(self, args)
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return rv;
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}
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static object *
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audioop_lin2adpcm(self, args)
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object *self;
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object *args;
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{
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signed char *cp;
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signed char *ncp;
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int len, size, val, step, valprev, delta, index, sign;
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object *rv, *state, *str;
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int i, outputbuffer, bufferstep;
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if ( !getargs(args, "(s#iO)",
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&cp, &len, &size, &state) )
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return 0;
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if ( size != 1 && size != 2 && size != 4) {
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err_setstr(AudioopError, "Size should be 1, 2 or 4");
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return 0;
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}
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str = newsizedstringobject(NULL, len/(size*2));
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if ( str == 0 )
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return 0;
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ncp = (signed char *)getstringvalue(str);
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/* Decode state, should have (value, step) */
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if ( state == None ) {
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/* First time, it seems. Set defaults */
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valprev = 0;
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step = 7;
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index = 0;
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} else if ( !getargs(state, "(iii)", &valprev, &step, &index) )
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return 0;
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bufferstep = 1;
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for ( i=0; i < len; i += size ) {
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if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
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else if ( size == 2 ) val = (int)*SHORTP(cp, i);
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else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
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/* Step 1 - compute difference with previous value */
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delta = val - valprev;
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sign = (delta < 0) ? 8 : 0;
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if ( sign ) delta = (-delta);
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/* Step 2 - Divide and clamp */
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#ifdef NODIVIDE
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Program using shifts and subtracts;
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#else
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delta = (delta<<2) / step;
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if ( delta > 7 ) delta = 7;
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#endif
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/* Step 3 - Update previous value */
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if ( sign )
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valprev -= (delta*step)>>2;
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else
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valprev += (delta*step)>>2;
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/* Step 4 - Clamp previous value to 16 bits */
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if ( valprev > 32767 )
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valprev = 32767;
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else if ( valprev < -32768 )
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valprev = -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 (as a whole byte, currently) */
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if ( bufferstep ) {
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outputbuffer = (delta << 4);
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} else {
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*ncp++ = delta | outputbuffer;
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}
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bufferstep = !bufferstep;
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}
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rv = mkvalue("(O(iii))", str, valprev, step, index);
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DECREF(str);
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return rv;
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}
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static object *
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audioop_adpcm2lin(self, args)
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object *self;
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object *args;
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{
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signed char *cp;
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signed char *ncp;
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int len, size, val, valprev, step, delta, index, sign;
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object *rv, *str, *state;
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int i, inputbuffer, bufferstep;
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if ( !getargs(args, "(s#iO)",
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&cp, &len, &size, &state) )
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return 0;
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if ( size != 1 && size != 2 && size != 4) {
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err_setstr(AudioopError, "Size should be 1, 2 or 4");
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return 0;
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}
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/* Decode state, should have (value, step) */
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if ( state == None ) {
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/* First time, it seems. Set defaults */
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valprev = 0;
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step = 7;
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index = 0;
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} else if ( !getargs(state, "(iii)", &valprev, &step, &index) )
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return 0;
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str = newsizedstringobject(NULL, len*size*2);
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if ( str == 0 )
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return 0;
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ncp = (signed char *)getstringvalue(str);
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bufferstep = 0;
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for ( i=0; i < len*size*2; i += size ) {
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/* Step 1 - get the delta value and compute next index */
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if ( bufferstep ) {
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delta = inputbuffer & 0xf;
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} else {
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inputbuffer = *cp++;
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delta = (inputbuffer >> 4) & 0xf;
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}
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bufferstep = !bufferstep;
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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 2 - Separate sign and magnitude */
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sign = delta & 8;
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delta = delta & 7;
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/* Step 3 - update output value */
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if ( sign )
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valprev -= (delta*step) >> 2;
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else
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valprev += (delta*step) >> 2;
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/* Step 4 - clamp output value */
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if ( valprev > 32767 )
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valprev = 32767;
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else if ( valprev < -32768 )
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valprev = -32768;
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/* Step 5 - Update step value */
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step = stepsizeTable[index];
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/* Step 6 - Output value */
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if ( size == 1 ) *CHARP(ncp, i) = (signed char)(valprev >> 8);
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else if ( size == 2 ) *SHORTP(ncp, i) = (short)(valprev);
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else if ( size == 4 ) *LONGP(ncp, i) = (long)(valprev<<16);
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}
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rv = mkvalue("(O(iii))", str, valprev, step, index);
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DECREF(str);
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return rv;
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}
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static struct methodlist audioop_methods[] = {
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{ "max", audioop_max },
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{ "avg", audioop_avg },
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@ -690,6 +877,8 @@ static struct methodlist audioop_methods[] = {
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{ "lin2ulaw", audioop_lin2ulaw },
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{ "adpcm2lin", audioop_adpcm2lin },
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{ "lin2adpcm", audioop_lin2adpcm },
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{ "adpcm32lin", audioop_adpcm32lin },
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{ "lin2adpcm3", audioop_lin2adpcm3 },
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{ "tomono", audioop_tomono },
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{ "tostereo", audioop_tostereo },
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{ "getsample", audioop_getsample },
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