[FFmpeg-trac] #10991(undetermined:new): Transcoding to x265 causes frozen frames

[FFmpeg]

#10991: Transcoding to x265 causes frozen frames
-------------------------------------+-------------------------------------
             Reporter:  Yuri         |                     Type:  defect
  Gorokhov                           |
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 Transcoding video to x265 results in a few frozen frames in the output
 video.

 How to reproduce:
 Download the input video:
 https://github.com/yurigorokhov/ffmpeg_bug/raw/main/265_bug_input_video.mov

 For context the input video was generated as such:

 {{{
 % ffmpeg -f lavfi \
     -i testsrc=size=1280x720:duration=50 \
     -vf
 "drawtext=text='%{n}':fontsize=72:x=(w-text_w)/2:y=(h-text_h)/2:fontcolor=white"
 \
     -c:v libx264 -preset ultrafast \
     265_bug_input_video.mov
 }}}

 Then transcode to x265

 {{{
 % ffmpeg -i 265_bug_input_video.mov -c:v libx265 -tag:v hvc1 \
     265_bug_frozen_frames.mov
 }}}

 Open the transcoded video and step through it frame by frame. At some
 point you will see that a sequence of frames is repeated. Unfortunately
 it's in a different time every time, but seems to be in the first 15
 seconds consistently.

 Here is a sample output video:
 https://github.com/yurigorokhov/ffmpeg_bug/raw/main/265_bug_frozen_frames.mov

 It is frozen in the frame range 245 -> 250
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10991>
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