[FFmpeg-cvslog] avformat/concatdec: Clip duration in one more case in get_best_effort_duration()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Jul 13 03:10:27 2025 +0200| [8cdb47e47a7a53a3c635a71bf712d79119eb86b4] | committer: Michael Niedermayer

avformat/concatdec: Clip duration in one more case in get_best_effort_duration()

Fixes: signed integer overflow: 40000 - -9223372036854770000 cannot be represented in type 'long'
Fixes: 427262541/clusterfuzz-testcase-minimized-ffmpeg_dem_CONCAT_fuzzer-4831506940100608

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Nicolas George <george at nsup.org>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8cdb47e47a7a53a3c635a71bf712d79119eb86b4
---

 libavformat/concatdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/concatdec.c b/libavformat/concatdec.c
index fe65d0c768..e0c2c87248 100644
--- a/libavformat/concatdec.c
+++ b/libavformat/concatdec.c
@@ -326,7 +326,7 @@ static int64_t get_best_effort_duration(ConcatFile *file, AVFormatContext *avf)
     if (file->outpoint != AV_NOPTS_VALUE)
         return av_sat_sub64(file->outpoint, file->file_inpoint);
     if (avf->duration > 0)
-        return avf->duration - (file->file_inpoint - file->file_start_time);
+        return av_sat_sub64(avf->duration, file->file_inpoint - file->file_start_time);
     if (file->next_dts != AV_NOPTS_VALUE)
         return file->next_dts - file->file_inpoint;
     return AV_NOPTS_VALUE;