[FFmpeg-trac] #8857(undetermined:new): ffmpeg h264_qsv force_key_frames incorret

FFmpeg trac at avcodec.org
Wed Dec 23 14:01:53 EET 2020


#8857: ffmpeg h264_qsv force_key_frames  incorret
-------------------------------------+-------------------------------------
             Reporter:  mikejson     |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  h264_qsv     |               Blocked By:
  force_key_frames                   |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by zimbler):

 * cc: zimbler@… (added)
 * keywords:  h264_qsv => h264_qsv force_key_frames


Comment:

 Same problem for me, only with force_key_frames parameter present.

 {{{
 ffmpeg  -y -i timecode.mp4 -init_hw_device qsv=foo:/dev/dri/renderD128
 -filter_hw_device foo -filter_complex
 "[0:v]format=nv12,hwupload=extra_hw_frames=64[v]" -map '[v]' -c:v h264_qsv
 -g 50 -flags +cgop -r 25 -keyint_min 49 -forced_idr 1 -force_key_frames
 "expr:gte(t,(n_forced*2)+ 2)" out_cgop.mp4

 ffprobe -show_frames -select_streams v:0 out_cgop.mp4 | egrep
 '(pict_type|key_frame|pkt_pts_time)' | xargs -n 3 echo | grep I
 }}}

 * without `force_key_frames` a key frame is set to every 50 frames.
 * with `force_key_frames`, first key frame is at 0:00:00.0, second ad
 0:02:00.0 and then randomly with average distance 2-5 frames.
 * two consequent launches produces different key frames, so there may be a
 race condition
 * output with or without `force_key_frames` is same and does not contain
 any warning or error.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8857#comment:3>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list