diff --git a/libavformat/mov.c b/libavformat/mov.c
index caba256161..9c5442988c 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7879,6 +7879,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
     }
 
     /* adjust stsd index */
+    if (sc->chunk_count) {
     time_sample = 0;
     for (i = 0; i < sc->stsc_count; i++) {
         int64_t next = time_sample + mov_get_stsc_samples(sc, i);
@@ -7890,6 +7891,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
         av_assert0(next == (int)next);
         time_sample = next;
     }
+    }
 
     return sample;
 }