@@ -3308,13 +3308,16 @@ static void mov_estimate_video_delay(MOVContext *c, AVStream* st) {

         for(ind = 0; ind < st->nb_index_entries && ctts_ind < msc->ctts_count; ++ind) {

             if (buf_size == (MAX_REORDER_DELAY + 1)) {

                 // If circular buffer is full, then move the first element forward.

-                buf_start = (buf_start + 1) % buf_size;

+                buf_start = (buf_start + 1);

+                if (buf_start == MAX_REORDER_DELAY + 1)

+                    buf_start = 0;

             } else {

                 ++buf_size;

             }

             // Point j to the last elem of the buffer and insert the current pts there.

-            j = (buf_start + buf_size - 1) % buf_size;

+            j = buf_start - 1;

+            if (j < 0) j = buf_size - 1;

             pts_buf[j] = st->index_entries[ind].timestamp + msc->ctts_data[ctts_ind].duration;

             // The timestamps that are already in the sorted buffer, and are greater than the

@@ -3325,7 +3328,8 @@ static void mov_estimate_video_delay(MOVContext *c, AVStream* st) {

             // go through, to keep this buffer in sorted order.

             num_swaps = 0;

             while (j != buf_start) {

-                r = (j - 1 + buf_size) % buf_size;

+                r = j - 1;

+                if (r < 0) r = buf_size - 1;

                 if (pts_buf[j] < pts_buf[r]) {

                     FFSWAP(int64_t, pts_buf[j], pts_buf[r]);

                     ++num_swaps;