[FFmpeg-cvslog] avformat/mov: Eliminate variable buf_size from mov_estimate_video_delay()

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jul 11 02:17:56 2018 +0200| [052edeec55fdcc977f1e3e7d89c9b616ae461a82] | committer: Michael Niedermayer

avformat/mov: Eliminate variable buf_size from mov_estimate_video_delay()

Reviewed-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
Reviewed-by: Sasi Inguva <isasi at google.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 3ce4034308a3726395a2c1b18a3dff3554e0b619)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=052edeec55fdcc977f1e3e7d89c9b616ae461a82
---

 libavformat/mov.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 1df6b3781f..b01d533eb4 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -3299,25 +3299,22 @@ static void mov_estimate_video_delay(MOVContext *c, AVStream* st) {
     int ctts_sample = 0;
     int64_t pts_buf[MAX_REORDER_DELAY + 1]; // Circular buffer to sort pts.
     int buf_start = 0;
-    int buf_size = 0;
     int j, r, num_swaps;
 
+    for (j = 0; j < MAX_REORDER_DELAY + 1; j++)
+        pts_buf[j] = INT64_MIN;
+
     if (st->codecpar->video_delay <= 0 && msc->ctts_data &&
         st->codecpar->codec_id == AV_CODEC_ID_H264) {
         st->codecpar->video_delay = 0;
         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);
-                if (buf_start == MAX_REORDER_DELAY + 1)
-                    buf_start = 0;
-            } else {
-                ++buf_size;
-            }
+            buf_start = (buf_start + 1);
+            if (buf_start == MAX_REORDER_DELAY + 1)
+                buf_start = 0;
 
             // Point j to the last elem of the buffer and insert the current pts there.
             j = buf_start - 1;
-            if (j < 0) j = buf_size - 1;
+            if (j < 0) j = MAX_REORDER_DELAY;
             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
@@ -3329,7 +3326,7 @@ static void mov_estimate_video_delay(MOVContext *c, AVStream* st) {
             num_swaps = 0;
             while (j != buf_start) {
                 r = j - 1;
-                if (r < 0) r = buf_size - 1;
+                if (r < 0) r = MAX_REORDER_DELAY;
                 if (pts_buf[j] < pts_buf[r]) {
                     FFSWAP(int64_t, pts_buf[j], pts_buf[r]);
                     ++num_swaps;