[FFmpeg-trac] #4554(undetermined:reopened): wrong seek with -ss

FFmpeg trac at avcodec.org
Sat Mar 17 15:20:40 EET 2018

#4554: wrong seek with -ss
             Reporter:               |                    Owner:
  josephine.dussourd                 |                   Status:  reopened
                 Type:  defect       |                Component:
             Priority:  normal       |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  mov h264     |               Blocked By:
  seek                               |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |

Comment (by oxd):

 Also seeing same issue with seeking as noirbee when using -ss as an input
 option and doing stream copy.

 In my case when I try to trim a video from a specific keyframe (using
 either same timestamp as keyframe or just afterwards) ffmpeg will seek to
 the previous keyframe. Michael's heuristic subtracts some amount from the
 timestamp that I entered resulting in the seek timestamp being earlier
 than my target keyframe.

 Target keyframe has DTS time of 50.005 any of the following commands are

 ffmpeg -y -noaccurate_seek -ss 50.005 -c copy -i test.mp4 test_out.mp4
 ffmpeg -y -noaccurate_seek -ss 50.055 -c copy -i test.mp4 test_out.mp4
 ffmpeg -y -noaccurate_seek -ss 50.105 -c copy -i test.mp4 test_out.mp4

 The resulting output will start from previous keyframe before 50.005, e.g.

Ticket URL: <https://trac.ffmpeg.org/ticket/4554#comment:8>
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