Fix to generate tones having one amplitude modulated by another: Bug #746

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1902 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/indications.c b/indications.c
index 180b948..864fd6a 100755 (executable)
--- a/indications.c
+++ b/indications.c
@@ -31,6 +31,7 @@ struct playtones_item {
        int freq1;
        int freq2;
        int duration;
+       int modulate;
 };
 
 struct playtones_def {
@@ -103,7 +104,15 @@ static int playtones_generator(struct ast_channel *chan, void *data, int len, in
 
        pi = &ps->items[ps->npos];
        for (x=0;x<len/2;x++) {
-               ps->data[x] = ps->vol * (
+               if (pi->modulate)
+               /* Modulate 1st tone with 2nd, to 90% modulation depth */
+               ps->data[x] = ps->vol * 2 * (
+                       sin((pi->freq1 * 2.0 * M_PI / 8000.0) * (ps->pos + x)) *
+                       (0.9 * fabs(sin((pi->freq2 * 2.0 * M_PI / 8000.0) * (ps->pos + x))) + 0.1)
+                       );
+               else
+                       /* Add 2 tones together */
+                       ps->data[x] = ps->vol * (
                                sin((pi->freq1 * 2.0 * M_PI / 8000.0) * (ps->pos + x)) +
                                sin((pi->freq2 * 2.0 * M_PI / 8000.0) * (ps->pos + x))
                        );
@@ -157,7 +166,7 @@ int ast_playtones_start(struct ast_channel *chan, int vol, const char *playlst,
                separator = ",";
        s = strsep(&stringp,separator);
         while(s && *s) {
-               int freq1, freq2, time;
+               int freq1, freq2, time, modulate=0;
 
                if (s[0]=='!')
                        s++;
@@ -168,6 +177,13 @@ int ast_playtones_start(struct ast_channel *chan, int vol, const char *playlst,
                } else if (sscanf(s, "%d+%d", &freq1, &freq2) == 2) {
                        /* f1+f2 format */
                        time = 0;
+               } else if (sscanf(s, "%d*%d/%d", &freq1, &freq2, &time) == 3) {
+                       /* f1*f2/time format */
+                       modulate = 1;
+               } else if (sscanf(s, "%d*%d", &freq1, &freq2) == 2) {
+                       /* f1*f2 format */
+                       time = 0;
+                       modulate = 1;
                } else if (sscanf(s, "%d/%d", &freq1, &time) == 2) {
                        /* f1/time format */
                        freq2 = 0;
@@ -186,6 +202,7 @@ int ast_playtones_start(struct ast_channel *chan, int vol, const char *playlst,
                d.items[d.nitems].freq1    = freq1;
                d.items[d.nitems].freq2    = freq2;
                d.items[d.nitems].duration = time;
+               d.items[d.nitems].modulate = modulate;
                d.nitems++;
 
                s = strsep(&stringp,separator);