MT#55283 extend codec_tracker_update

Allow codec_tracker_update to reference an existing codec_store. Then
when a supplemental codec type needs to be generated, make it look up
the type in the existing codec_store and re-use the existing payload
type if present instead of creating a new one. This allows payload type
numbers to remain unchanged during a re-invite.

Change-Id: I9e5edd897515a5e3eb5033aa6bbf21c8667d6133

daemon/call.c

@@ -2446,14 +2446,14 @@ static void codecs_offer(struct call_media *media, struct call_media *other_medi
 	codec_store_synthesise(&media->codecs, &other_media->codecs);
 
 	// update supp codecs based on actions so far
-	codec_tracker_update(&media->codecs);
+	codec_tracker_update(&media->codecs, &sp->codecs);
 
 	// set up handlers
 	codec_handlers_update(media, other_media, .flags = flags, .sp = sp,
 			.allow_asymmetric = !!(flags && flags->allow_asymmetric_codecs));
 
 	// updating the handlers may have removed some codecs, so run update the supp codecs again
-	codec_tracker_update(&media->codecs);
+	codec_tracker_update(&media->codecs, &sp->codecs);
 
 	// finally set up handlers again based on final results
 
@@ -2506,8 +2506,8 @@ static void codecs_answer(struct call_media *media, struct call_media *other_med
 			.allow_asymmetric = !!flags->allow_asymmetric_codecs);
 
 	// updating the handlers may have removed some codecs, so run update the supp codecs again
-	codec_tracker_update(&media->codecs);
+	codec_tracker_update(&media->codecs, NULL);
-	codec_tracker_update(&other_media->codecs);
+	codec_tracker_update(&other_media->codecs, NULL);
 
 	// finally set up handlers again based on final results
 

daemon/codec.c

@@ -4678,7 +4678,7 @@ static int ptr_cmp(const void *a, const void *b) {
 		return 1;
 	return 0;
 }
-void codec_tracker_update(struct codec_store *cs) {
+void codec_tracker_update(struct codec_store *cs, struct codec_store *orig_cs) {
 	if (!cs)
 		return;
 	struct codec_tracker *sct = cs->tracker;
@@ -4732,7 +4732,23 @@ void codec_tracker_update(struct codec_store *cs) {
 				= g_strdup_printf(STR_FORMAT "/%u", STR_FMT(supp_codec), clockrate);
 			str pt_str = STR_INIT(pt_s);
 
-			struct rtp_payload_type *pt = codec_add_payload_type(&pt_str, cs->media, NULL, NULL);
+			// see if we have a matching PT from before
+			struct rtp_payload_type *pt = NULL;
+			if (orig_cs) {
+				GQueue *ptq = g_hash_table_lookup(orig_cs->codec_names, &pt_str);
+				if (ptq) {
+					for (GList *n = ptq->head; n; n = n->next) {
+						pt = g_hash_table_lookup(orig_cs->codecs, n->data);
+						if (!pt)
+							continue;
+						pt = rtp_payload_type_dup(pt);
+						break;
+					}
+				}
+			}
+
+			if (!pt)
+				pt = codec_add_payload_type(&pt_str, cs->media, NULL, NULL);
 			if (!pt)
 				continue;
 

include/codec.h

@@ -190,7 +190,7 @@ uint64_t codec_last_dtmf_event(struct codec_ssrc_handler *ch);
 uint64_t codec_encoder_pts(struct codec_ssrc_handler *ch, struct ssrc_ctx *);
 void codec_decoder_skip_pts(struct codec_ssrc_handler *ch, uint64_t);
 uint64_t codec_decoder_unskip_pts(struct codec_ssrc_handler *ch);
-void codec_tracker_update(struct codec_store *);
+void codec_tracker_update(struct codec_store *, struct codec_store *);
 void codec_handlers_stop(GQueue *, struct call_media *sink);
 
 
@@ -229,7 +229,7 @@ INLINE void __codec_handlers_update(struct call_media *receiver, struct call_med
 {
 }
 INLINE void codec_handler_free(struct codec_handler **handler) { }
-INLINE void codec_tracker_update(struct codec_store *cs) { }
+INLINE void codec_tracker_update(struct codec_store *cs, struct codec_store *ocs) { }
 INLINE void codec_handlers_stop(GQueue *q, struct call_media *sink) { }
 INLINE void ensure_codec_def(struct rtp_payload_type *pt, struct call_media *media) { }