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

[1035567130@qq.com]

From: Wang Yaqiang <wangyaqiang03@kuaishou.com>

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@kuaishou.com>
---
 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;
-- 
2.39.2

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