[FFmpeg-trac] #7506(undetermined:new): EIA-608 Closed Captions distortion on the output.

[FFmpeg]

#7506: EIA-608 Closed Captions distortion on the output.
-------------------------------------+-------------------------------------
             Reporter:  w_boba       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
  EIA-608,a53cc, closed captions     |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 How to reproduce:
 {{{
 % ffmpeg.exe -y -v 99 -loglevel 99 -i sample-1min.ts -c:a aac -c:v libx264
 sample-1min.mp4
 }}}


 {{{
 ffmpeg version N-92202-gf72b9904fe Copyright (c) 2000-2018 the FFmpeg
 developers
   built with gcc 8.2.1 (GCC) 20181017
   configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
 fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-
 libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-
 amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus
 --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora
 --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp
 --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg
 --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-
 libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex
 --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-
 ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec
 --enable-dxva2 --enable-avisynth
   libavutil      56. 19.101 / 56. 19.101
   libavcodec     58. 33.101 / 58. 33.101
   libavformat    58. 19.100 / 58. 19.100
   libavdevice    58.  4.105 / 58.  4.105
   libavfilter     7. 33.101 /  7. 33.101
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
   libpostproc    55.  2.100 / 55.  2.100
 }}}


 When I try to re-encode some MPEG2 TS files into h.264/mp4 using libx264
 for encoder, embedded closed captions are not properly passed through to
 output file. It looks to me like CCs are doubled for some reason.


 Original CCs (got them with CCextractor tool) look like this:
 {{{
 1
 00:00:01,751 --> 00:00:03,469
         Yup, so you just
        want a nice layer.

 2
 00:00:03,536 --> 00:00:04,670
        That's good there.

 3
 00:00:04,721 --> 00:00:06,305
       Potatoes are ready.

 4
 00:00:06,372 --> 00:00:08,090
   This gets covered in
  your famous pot crack?
 }}}

 While extracted from MP4 file after re-encoding - they look like this:

 {{{
 1
 00:00:01,234 --> 00:00:03,034
    So we'e're makaking B.C. h h?

 2
 00:00:03,036 --> 00:00:04,703
         YuYup, so you u just
        want a  nice layerer.

 3
 00:00:04,871 --> 00:00:06,004
        That''s goodod there.

 4
 00:00:06,105 --> 00:00:07,672
       Potatoes a are ready..
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7506>
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