[FFmpeg-cvslog] avformat/movenc: fixed fmp4 packets containing incorrect flags after transcoding

[Wang Yaqiang]

ffmpeg | branch: master | Wang Yaqiang <wangyaqiang03 at kuaishou.com> | Mon Apr 10 20:43:26 2023 +0800| [734a61d282b9cfc89a1e4e7bb174d80f4cce3d88] | committer: Steven Liu

avformat/movenc: fixed fmp4 packets containing incorrect flags after transcoding

When write multi-trun box, the MOV_TRUN_FIRST_SAMPLE_FLAGS flag
need judge by first param, not 0.
If the original video contains consecutive I frames,
this will cause the packets of fmp4 have error sample_flags ,
and then incorrect keyframes were generated,
and then error packet will be seeked.

Signed-off-by: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
Signed-off-by: Steven Liu <liuqi05 at chinaffmpeg.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=734a61d282b9cfc89a1e4e7bb174d80f4cce3d88
---

 libavformat/movenc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index c370922c7d..946e79c5ac 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -4858,8 +4858,8 @@ static int mov_write_trun_tag(AVIOContext *pb, MOVMuxContext *mov,
         if (i > first && get_sample_flags(track, &track->cluster[i]) != track->default_sample_flags)
             flags |= MOV_TRUN_SAMPLE_FLAGS;
     }
-    if (!(flags & MOV_TRUN_SAMPLE_FLAGS) && track->entry > 0 &&
-         get_sample_flags(track, &track->cluster[0]) != track->default_sample_flags)
+    if (!(flags & MOV_TRUN_SAMPLE_FLAGS) && track->entry > first &&
+         get_sample_flags(track, &track->cluster[first]) != track->default_sample_flags)
         flags |= MOV_TRUN_FIRST_SAMPLE_FLAGS;
     if (track->flags & MOV_TRACK_CTTS)
         flags |= MOV_TRUN_SAMPLE_CTS;