Added conversions to/from ADPCM(-4); renamed adpcm to adpcm3 (what it
really was).
diff --git a/Modules/audioop.c b/Modules/audioop.c
index c3176f9..d37ce8f 100644
--- a/Modules/audioop.c
+++ b/Modules/audioop.c
@@ -130,9 +130,27 @@
}
/* End of code taken from sox */
-/* ADPCM step variation table */
+/* ADPCM-3 step variation table */
static float newstep[5] = { 0.8, 0.9, 1.0, 1.75, 1.75 };
+/* 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
+};
+
#define CHARP(cp, i) ((signed char *)(cp+i))
#define SHORTP(cp, i) ((short *)(cp+i))
#define LONGP(cp, i) ((long *)(cp+i))
@@ -550,7 +568,7 @@
}
static object *
-audioop_lin2adpcm(self, args)
+audioop_lin2adpcm3(self, args)
object *self;
object *args;
{
@@ -619,7 +637,7 @@
}
static object *
-audioop_adpcm2lin(self, args)
+audioop_adpcm32lin(self, args)
object *self;
object *args;
{
@@ -679,6 +697,175 @@
return rv;
}
+static object *
+audioop_lin2adpcm(self, args)
+ object *self;
+ object *args;
+{
+ signed char *cp;
+ signed char *ncp;
+ int len, size, val, step, valprev, delta, index, sign;
+ object *rv, *state, *str;
+ int i, outputbuffer, bufferstep;
+
+ if ( !getargs(args, "(s#iO)",
+ &cp, &len, &size, &state) )
+ return 0;
+
+
+ if ( size != 1 && size != 2 && size != 4) {
+ err_setstr(AudioopError, "Size should be 1, 2 or 4");
+ return 0;
+ }
+
+ str = newsizedstringobject(NULL, len/(size*2));
+ if ( str == 0 )
+ return 0;
+ ncp = (signed char *)getstringvalue(str);
+
+ /* Decode state, should have (value, step) */
+ if ( state == None ) {
+ /* First time, it seems. Set defaults */
+ valprev = 0;
+ step = 7;
+ index = 0;
+ } else if ( !getargs(state, "(iii)", &valprev, &step, &index) )
+ return 0;
+
+ bufferstep = 1;
+
+ for ( i=0; i < len; i += size ) {
+ if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
+ else if ( size == 2 ) val = (int)*SHORTP(cp, i);
+ else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
+
+ /* Step 1 - compute difference with previous value */
+ delta = val - valprev;
+ sign = (delta < 0) ? 8 : 0;
+ if ( sign ) delta = (-delta);
+
+ /* Step 2 - Divide and clamp */
+#ifdef NODIVIDE
+ Program using shifts and subtracts;
+#else
+ delta = (delta<<2) / step;
+ if ( delta > 7 ) delta = 7;
+#endif
+
+ /* Step 3 - Update previous value */
+ if ( sign )
+ valprev -= (delta*step)>>2;
+ else
+ valprev += (delta*step)>>2;
+
+ /* Step 4 - Clamp previous value to 16 bits */
+ if ( valprev > 32767 )
+ valprev = 32767;
+ else if ( valprev < -32768 )
+ valprev = -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 (as a whole byte, currently) */
+ if ( bufferstep ) {
+ outputbuffer = (delta << 4);
+ } else {
+ *ncp++ = delta | outputbuffer;
+ }
+ bufferstep = !bufferstep;
+ }
+ rv = mkvalue("(O(iii))", str, valprev, step, index);
+ DECREF(str);
+ return rv;
+}
+
+static object *
+audioop_adpcm2lin(self, args)
+ object *self;
+ object *args;
+{
+ signed char *cp;
+ signed char *ncp;
+ int len, size, val, valprev, step, delta, index, sign;
+ object *rv, *str, *state;
+ int i, inputbuffer, bufferstep;
+
+ if ( !getargs(args, "(s#iO)",
+ &cp, &len, &size, &state) )
+ return 0;
+
+ if ( size != 1 && size != 2 && size != 4) {
+ err_setstr(AudioopError, "Size should be 1, 2 or 4");
+ return 0;
+ }
+
+ /* Decode state, should have (value, step) */
+ if ( state == None ) {
+ /* First time, it seems. Set defaults */
+ valprev = 0;
+ step = 7;
+ index = 0;
+ } else if ( !getargs(state, "(iii)", &valprev, &step, &index) )
+ return 0;
+
+ str = newsizedstringobject(NULL, len*size*2);
+ if ( str == 0 )
+ return 0;
+ ncp = (signed char *)getstringvalue(str);
+
+ bufferstep = 0;
+
+ for ( i=0; i < len*size*2; i += size ) {
+ /* Step 1 - get the delta value and compute next index */
+ if ( bufferstep ) {
+ delta = inputbuffer & 0xf;
+ } else {
+ inputbuffer = *cp++;
+ delta = (inputbuffer >> 4) & 0xf;
+ }
+
+ bufferstep = !bufferstep;
+
+ index += indexTable[delta];
+ if ( index < 0 ) index = 0;
+ if ( index > 88 ) index = 88;
+
+ /* Step 2 - Separate sign and magnitude */
+ sign = delta & 8;
+ delta = delta & 7;
+
+ /* Step 3 - update output value */
+ if ( sign )
+ valprev -= (delta*step) >> 2;
+ else
+ valprev += (delta*step) >> 2;
+
+ /* Step 4 - clamp output value */
+ if ( valprev > 32767 )
+ valprev = 32767;
+ else if ( valprev < -32768 )
+ valprev = -32768;
+
+ /* Step 5 - Update step value */
+ step = stepsizeTable[index];
+
+ /* Step 6 - Output value */
+ if ( size == 1 ) *CHARP(ncp, i) = (signed char)(valprev >> 8);
+ else if ( size == 2 ) *SHORTP(ncp, i) = (short)(valprev);
+ else if ( size == 4 ) *LONGP(ncp, i) = (long)(valprev<<16);
+ }
+
+ rv = mkvalue("(O(iii))", str, valprev, step, index);
+ DECREF(str);
+ return rv;
+}
+
static struct methodlist audioop_methods[] = {
{ "max", audioop_max },
{ "avg", audioop_avg },
@@ -690,6 +877,8 @@
{ "lin2ulaw", audioop_lin2ulaw },
{ "adpcm2lin", audioop_adpcm2lin },
{ "lin2adpcm", audioop_lin2adpcm },
+ { "adpcm32lin", audioop_adpcm32lin },
+ { "lin2adpcm3", audioop_lin2adpcm3 },
{ "tomono", audioop_tomono },
{ "tostereo", audioop_tostereo },
{ "getsample", audioop_getsample },