#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>
FFmpeg <https://ffmpeg.org>
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