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--- src/ptclib/dtmf.cxx.old 2007-10-19 02:22:33.000000000 -0400
+++ src/ptclib/dtmf.cxx 2008-01-05 21:17:37.000000000 -0500
@@ -121,6 +121,64 @@
}
+PString PDTMFDecoder::Decode(const void *buf, PINDEX bytes)
+{
+ int x;
+ int s, kk;
+ int c, d, f, n;
+ short *buffer = (short *)buf;
+
+ PINDEX numSamples = bytes >> 1;
+
+ PString keyString;
+
+ PINDEX pos;
+ for (pos = 0; pos < numSamples; pos++) {
+
+ /* Read (and scale) the next 16 bit sample */
+ x = ((int)(*buffer++)) / (32768/FSC);
+
+ /* Input amplitude */
+ if (x > 0)
+ ia += (x - ia) / 128;
+ else
+ ia += (-x - ia) / 128;
+
+ /* For each tone */
+ s = 0;
+ for(kk = 0; kk < 8; kk++) {
+
+ /* Turn the crank */
+ c = (P2 * (x - k[kk])) / FSC;
+ d = x + c;
+ f = (p1[kk] * (d - h[kk])) / FSC;
+ n = x - k[kk] - c;
+ k[kk] = h[kk] + f;
+ h[kk] = f + d;
+
+ /* Detect and Average */
+ if (n > 0)
+ y[kk] += (n - y[kk]) / 64;
+ else
+ y[kk] += (-n - y[kk]) / 64;
+
+ /* Threshold */
+ if (y[kk] > FSC/10 && y[kk] > ia)
+ s |= 1 << kk;
+ }
+
+ /* Hysteresis and noise supressor */
+ if (s != so) {
+ nn = 0;
+ so = s;
+ } else if (nn++ == 520 && s < 256 && key[s] != '?') {
+ PTRACE(3,"DTMF\tDetected '" << key[s] << "' in PCM-16 stream");
+ keyString += key[s];
+ }
+ }
+ return keyString;
+}
+
PString PDTMFDecoder::Decode(const short * sampleData, PINDEX numSamples)
{
int x;
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