TT#121752 fix RTCP RR SSRC substitution when transcoding

Perform reverse SSRC mapping even if output media is not known, and use
the appropriate media side when looking up SSRCs for received RTCP
timestamps.

closes #1298

Change-Id: Ifa5a982163bf7b0510ffc2a92ae25995d1adb888

daemon/rtcp.c

@@ -1307,7 +1307,7 @@ static void transcode_rr(struct rtcp_process_ctx *ctx, struct report_block *rr)
 		return;
 	if (ctx->scratch.rr.from != ctx->mp->ssrc_in->parent->h.ssrc)
 		return;
-	if (!ctx->mp->media || !ctx->mp->media_out)
+	if (!ctx->mp->media)
 		return;
 
 	// reverse SSRC mapping
@@ -1315,6 +1315,9 @@ static void transcode_rr(struct rtcp_process_ctx *ctx, struct report_block *rr)
 			SSRC_DIR_OUTPUT, ctx->mp->media->monologue);
 	rr->ssrc = htonl(map_ctx->ssrc_map_out);
 
+	if (!ctx->mp->media_out)
+		return;
+
 	// for reception stats
 	struct ssrc_ctx *input_ctx = get_ssrc_ctx(map_ctx->ssrc_map_out,
 			ctx->mp->media_out->monologue->ssrc_hash,

daemon/ssrc.c

@@ -274,13 +274,22 @@ static long long __calc_rtt(struct call_monologue *ml, uint32_t ssrc, uint32_t n
 	if (!ntp_middle_bits || !delay)
 		return 0;
 
-	struct ssrc_entry_call *e = hunt_ssrc(ml, ssrc);
+	struct ssrc_entry_call *e = find_ssrc(ssrc, ml->ssrc_hash);
 	if (G_UNLIKELY(!e))
 		return 0;
 
 	if (pt_p)
 		*pt_p = e->output_ctx.tracker.most[0] == 255 ? -1 : e->output_ctx.tracker.most[0];
 
+	// grab the opposite side SSRC for the time reports
+	uint32_t map_ssrc = e->output_ctx.ssrc_map_out;
+	if (!map_ssrc)
+		map_ssrc = e->h.ssrc;
+	obj_put(&e->h);
+	e = hunt_ssrc(ml, map_ssrc);
+	if (G_UNLIKELY(!e))
+		return 0;
+
 	struct ssrc_time_item *sti;
 	GQueue *q = (((void *) e) + reports_queue_offset);
 	mutex_lock(&e->h.lock);