TT#14008 fix transcoding logic

Transcoding should not be decided based on the name of the codec alone,
but primarily on the payload type. First the PT needs to be compared,
then the codec type must be confirmed.

closes #1289

Change-Id: I1a8bffc6d521443aba14d9b4cf1ad4d1e21f1226

daemon/codec.c

@@ -1454,13 +1454,12 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 				receiver_transcoding,
 				transcode_supplemental, pcm_dtmf_detect);
 
-		struct rtp_payload_type *dest_pt; // transcode to this
+		struct rtp_payload_type *dest_pt = NULL; // transcode to this
 
-		GQueue *dest_codecs = NULL;
 		if (pref_dest_codec->for_transcoding) {
 			// with force accepted codec, we still accept DTMF payloads if possible
 			if (pt->codec_def && pt->codec_def->supplemental)
-				dest_codecs = g_hash_table_lookup(sink->codec_names_send, &pt->encoding);
+				dest_pt = g_hash_table_lookup(sink->codecs_send, GINT_TO_POINTER(pt->payload_type));
 		}
 		else {
 			// we ignore output codec matches if we must transcode supp codecs
@@ -1471,24 +1470,8 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 			else if (pcm_dtmf_detect)
 				;
 			else
-				dest_codecs = g_hash_table_lookup(sink->codec_names_send, &pt->encoding);
-		}
-		if (dest_codecs) {
-			// the sink supports this codec - check offered formats
-			dest_pt = NULL;
-			for (GList *k = dest_codecs->head; k; k = k->next) {
-				unsigned int dest_ptype = GPOINTER_TO_UINT(k->data);
-				dest_pt = g_hash_table_lookup(sink->codecs_send, GINT_TO_POINTER(dest_ptype));
-				if (!dest_pt)
-					continue;
-				if (dest_pt->clock_rate != pt->clock_rate ||
-						dest_pt->channels != pt->channels) {
-					dest_pt = NULL;
-					continue;
+				dest_pt = g_hash_table_lookup(sink->codecs_send, GINT_TO_POINTER(pt->payload_type));
 		}
-				break;
-			}
-
 		if (!dest_pt)
 			goto unsupported;
 
@@ -1523,7 +1506,6 @@ void codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 		if (pt->codec_def && pt->codec_def->dtmf)
 			__dtmf_dsp_shutdown(sink, pt->payload_type);
 		goto next;
-		}
 
 unsupported:
 		// the sink does not support this codec -> transcode