diff --git a/libavformat/mov.c b/libavformat/mov.c
index 06ea76a5da..6e196f31c1 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1753,6 +1753,9 @@ static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         sc->ctts_data[i].count   = count;
         sc->ctts_data[i].duration= duration;
 
+        av_dlog(c->fc, "count=%d, duration=%d\n",
+                count, duration);
+
         if (FFABS(duration) > (1<<28) && i+2<entries) {
             av_log(c->fc, AV_LOG_WARNING, "CTTS invalid\n");
             av_freep(&sc->ctts_data);