From 3f3e60dd7aaf369d4b7cf740f88c92781c65626c Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Sat, 18 Feb 2023 17:37:58 +0100
Subject: [PATCH] Do not merge config audio packets

For video streams (at least H.264 and H.265), the config packet
containing SPS/PPS must be prepended to the next packet (the following
keyframe).

For audio streams (at least OPUS), they must not be merged.
---
 app/src/demuxer.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/app/src/demuxer.c b/app/src/demuxer.c
index 6089e614..53a0effe 100644
--- a/app/src/demuxer.c
+++ b/app/src/demuxer.c
@@ -191,8 +191,15 @@ run_demuxer(void *data) {
         goto end;
     }
 
+    // Config packets must be merged with the next non-config packet only for
+    // video streams
+    bool must_merge_config_packet = codec->type == AVMEDIA_TYPE_VIDEO;
+
     struct sc_packet_merger merger;
-    sc_packet_merger_init(&merger);
+
+    if (must_merge_config_packet) {
+        sc_packet_merger_init(&merger);
+    }
 
     AVPacket *packet = av_packet_alloc();
     if (!packet) {
@@ -208,11 +215,13 @@ run_demuxer(void *data) {
             break;
         }
 
-        // Prepend any config packet to the next media packet
-        ok = sc_packet_merger_merge(&merger, packet);
-        if (!ok) {
-            av_packet_unref(packet);
-            break;
+        if (must_merge_config_packet) {
+            // Prepend any config packet to the next media packet
+            ok = sc_packet_merger_merge(&merger, packet);
+            if (!ok) {
+                av_packet_unref(packet);
+                break;
+            }
         }
 
         ok = sc_demuxer_push_packet(demuxer, packet);
@@ -225,7 +234,9 @@ run_demuxer(void *data) {
 
     LOGD("End of frames");
 
-    sc_packet_merger_destroy(&merger);
+    if (must_merge_config_packet) {
+        sc_packet_merger_destroy(&merger);
+    }
 
     av_packet_free(&packet);
 finally_close_sinks: