[FFmpeg-trac] #7694(avcodec:new): Decoding EIA-608 closed captions in MP4 (created by Final Cut Pro) not working

FFmpeg trac at avcodec.org
Wed Jan 23 08:33:58 EET 2019


#7694: Decoding EIA-608 closed captions in MP4 (created by Final Cut Pro) not
working
------------------------------------+--------------------------------------
             Reporter:  fumoboy007  |                     Type:  defect
               Status:  new         |                 Priority:  normal
            Component:  avcodec     |                  Version:  git-master
             Keywords:              |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+--------------------------------------
 = Summary of the bug

 I created an MP4 using Final Cut Pro that contains EIA-608 closed
 captions. (The closed captions are muxed by Final Cut Pro as a separate
 stream from the video.) I tried playing this file using `ffplay`, VLC, and
 my own video application that uses the FFmpeg libraries; the closed
 captions are not shown.

 More specifically, `avcodec_decode_subtitle2` always returns `0` into
 `got_sub_ptr`.

 = How to reproduce

 Download the attached sample file and then run the following command:

 {{{
 % ffplay FFmpeg\ EIA-608\ Bug.m4v
 ffplay version 4.1 Copyright (c) 2003-2018 the FFmpeg developers
   built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1_1 --enable-shared
 --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-
 avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay
 --enable-gpl --enable-libmp3lame --enable-libopus --enable-libsnappy
 --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264
 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfreetype
 --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-
 libopencore-amrwb --enable-librtmp --enable-libspeex --enable-videotoolbox
   libavutil      56. 22.100 / 56. 22.100
   libavcodec     58. 35.100 / 58. 35.100
   libavformat    58. 20.100 / 58. 20.100
   libavdevice    58.  5.100 / 58.  5.100
   libavfilter     7. 40.101 /  7. 40.101
   libavresample   4.  0.  0 /  4.  0.  0
   libswscale      5.  3.100 /  5.  3.100
   libswresample   3.  3.100 /  3.  3.100
   libpostproc    55.  3.100 / 55.  3.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'FFmpeg EIA-608 Bug.m4v':
   Metadata:
     major_brand     : M4V
     minor_version   : 1
     compatible_brands: M4V M4A mp42isom
     creation_time   : 2019-01-23T06:04:07.000000Z
   Duration: 00:00:09.44, start: 0.000000, bitrate: 4165 kb/s
     Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz,
 stereo, fltp, 124 kb/s (default)
     Metadata:
       creation_time   : 2019-01-23T06:04:07.000000Z
       handler_name    : Core Media Audio
     Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv,
 bt709, progressive), 960x540 [SAR 1:1 DAR 16:9], 4034 kb/s, 25 fps, 25
 tbr, 25 tbn, 50 tbc (default)
     Metadata:
       creation_time   : 2019-01-23T06:04:07.000000Z
       handler_name    : Core Media Video
     Stream #0:2(eng): Subtitle: eia_608 (c608 / 0x38303663), 960x540, 0
 kb/s (default)
     Metadata:
       creation_time   : 2019-01-23T06:04:07.000000Z
       handler_name    : Core Media Closed Caption
 }}}

 I have also attached an SCC file (generated by Final Cut Pro) that
 contains only the closed captions.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7694>
FFmpeg <https://ffmpeg.org>
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