[FFmpeg-devel] [PATCH v2] avformat/mov: fix timecode with counter mode flag set

[mindmark at gmail.com]

From: Mark Reid <mindmark at gmail.com>

The current behaviour ends up squaring the avg_frame_rate if the conter mode flag is set.
This messes up the timecode calculation, and looks to me as a regression that
seems to have been introduced 428b4aac.

Upon further testing is seems that no special case is need for having the counter flag set. 
av_timecode_init appears to handles the timecode correctly, at least in the sample files
I have.

Here is a sample mov file with the counter flag set
https://www.dropbox.com/s/5l4fucb9lhq523s/timecode_counter_mode.mov

before the patch ffmpeg will report the timecode as:
00:37:11:97 and warns that the timecode framerate is 576000000/1002001

after patch:
14:50:55:02

---
 libavformat/mov.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 3215b53636..f8856a43dd 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2350,19 +2350,6 @@ FF_DISABLE_DEPRECATION_WARNINGS
             st->codec->time_base = av_inv_q(st->avg_frame_rate);
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
-            /* adjust for per frame dur in counter mode */
-            if (tmcd_ctx->tmcd_flags & 0x0008) {
-                int timescale = AV_RB32(st->codecpar->extradata + 8);
-                int framedur = AV_RB32(st->codecpar->extradata + 12);
-                st->avg_frame_rate.num *= timescale;
-                st->avg_frame_rate.den *= framedur;
-#if FF_API_LAVF_AVCTX
-FF_DISABLE_DEPRECATION_WARNINGS
-                st->codec->time_base.den *= timescale;
-                st->codec->time_base.num *= framedur;
-FF_ENABLE_DEPRECATION_WARNINGS
-#endif
-            }
             if (size > 30) {
                 uint32_t len = AV_RB32(st->codecpar->extradata + 18); /* name atom length */
                 uint32_t format = AV_RB32(st->codecpar->extradata + 22);
-- 
2.21.1 (Apple Git-122.3)