[FFmpeg-cvslog] avformat/demux: Fix segfault due to avcodec_open2 failure

[Pavel Koshevoy]

ffmpeg | branch: master | Pavel Koshevoy <pkoshevoy at gmail.com> | Fri Jun 27 19:31:26 2025 -0600| [59a6660625675c8343f3de858b93c8294f05bb52] | committer: Pavel Koshevoy

avformat/demux: Fix segfault due to avcodec_open2 failure

Fixes 'ffprobe 1_poc.mp4' segfault introduced with
commit 0021484d05f9b0f032fa319399de6e24eea0c04f

codec_close should not assume that the codec_id did not change.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=59a6660625675c8343f3de858b93c8294f05bb52
---

 libavformat/demux.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index ecd4f40da9..3749ab67a3 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1292,9 +1292,15 @@ static int codec_close(FFStream *sti)
 {
     AVCodecContext *avctx_new = NULL;
     AVCodecParameters *par_tmp = NULL;
+    const AVCodec *new_codec = NULL;
     int ret;
 
-    avctx_new = avcodec_alloc_context3(sti->avctx->codec);
+    new_codec =
+      (sti->avctx->codec_id != sti->pub.codecpar->codec_id) ?
+      avcodec_find_decoder(sti->pub.codecpar->codec_id) :
+      sti->avctx->codec;
+
+    avctx_new = avcodec_alloc_context3(new_codec);
     if (!avctx_new) {
         ret = AVERROR(ENOMEM);
         goto fail;