[FFmpeg-trac] #7912(undetermined:open): timing is all wrong when extract srt subtitle from video

[FFmpeg]

#7912: timing is all wrong when extract srt subtitle from video
-------------------------------------+-------------------------------------
             Reporter:  jookiyaya    |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  cc           |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by cehoyos):

 * keywords:   => cc
 * status:  new => open
 * version:  unspecified => git-master
 * reproduced:  0 => 1


Comment:

 For future tickets: Please always test current FFmpeg git head, nothing
 else is supported, and provide the command line you tested together with
 the complete, uncut console output.
 {{{
 $ ffmpeg -f lavfi -i movie=SrG.mkv[out+subcc] out.srt
 ffmpeg version N-93886-gfbdb3aa179 Copyright (c) 2000-2019 the FFmpeg
 developers
   built with gcc 8 (SUSE Linux)
   configuration: --enable-gpl --enable-gnutls --enable-libxml2 --enable-
 libx264 --enable-libx265 --enable-libvpx --enable-libaom --enable-libdav1d
 --enable-libmfx
   libavutil      56. 28.100 / 56. 28.100
   libavcodec     58. 52.101 / 58. 52.101
   libavformat    58. 27.103 / 58. 27.103
   libavdevice    58.  7.100 / 58.  7.100
   libavfilter     7. 53.101 /  7. 53.101
   libswscale      5.  4.101 /  5.  4.101
   libswresample   3.  4.100 /  3.  4.100
   libpostproc    55.  4.100 / 55.  4.100
 Input #0, lavfi, from 'movie=SrG.mkv[out+subcc]':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1280x720
 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 1k tbn, 1k tbc
     Stream #0:1: Subtitle: eia_608
 Output #0, srt, to 'out.srt':
   Metadata:
     encoder         : Lavf58.27.103
     Stream #0:0: Subtitle: subrip (srt)
     Metadata:
       encoder         : Lavc58.52.101 srt
 Stream mapping:
   Stream #0:1 -> #0:0 (eia_608 (cc_dec) -> subrip (srt))
 Press [q] to stop, [?] for help
 size=      15kB time=00:00:03.27 bitrate=  38.2kbits/s speed=0.114x
 video:0kB audio:0kB subtitle:10kB other streams:0kB global headers:0kB
 muxing overhead: 48.054531%
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/7912#comment:1>
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