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;