[FFmpeg-trac] #8410(ffmpeg:new): wishlist vtt: support styling when converting to ass

FFmpeg trac at avcodec.org
Mon Dec 2 13:15:32 EET 2019


#8410: wishlist vtt: support styling when converting to ass
-------------------------------------+-------------------------------------
             Reporter:  pan93412     |                     Type:  defect
               Status:  new          |                 Priority:  wish
            Component:  ffmpeg       |                  Version:  4.2
             Keywords:  wishlist,    |               Blocked By:
  vtt, ass, subtitle                 |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 == Summary of the bug
 When I convert a vtt file to ass, it appears like styles are removed.

 == How to reproduce
 === Logs
 {{{#!bash
 $ ffmpeg -i AIAIAI.zh-TW.vtt -f ass out.ass
 ffmpeg version n4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
   built with gcc 9.2.0 (GCC)
   configuration: --prefix=/usr --disable-debug --disable-static --disable-
 stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl
 --enable-ladspa --enable-libaom --enable-libass --enable-libbluray
 --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi
 --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug
 --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb
 --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr
 --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2
 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp
 --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2
 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-
 shared --enable-version3
   libavutil      56. 31.100 / 56. 31.100
   libavcodec     58. 54.100 / 58. 54.100
   libavformat    58. 29.100 / 58. 29.100
   libavdevice    58.  8.100 / 58.  8.100
   libavfilter     7. 57.100 /  7. 57.100
   libswscale      5.  5.100 /  5.  5.100
   libswresample   3.  5.100 /  3.  5.100
   libpostproc    55.  5.100 / 55.  5.100
 [webvtt @ 0x5648bc272780] Dropping 2 duplicated subtitle events
 Input #0, webvtt, from 'AIAIAI.zh-TW.vtt':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Subtitle: webvtt
 Output #0, ass, to 'out.ass':
   Metadata:
     encoder         : Lavf58.29.100
     Stream #0:0: Subtitle: ass (ssa)
     Metadata:
       encoder         : Lavc58.54.100 ssa
 Stream mapping:
   Stream #0:0 -> #0:0 (webvtt (native) -> ass (ssa))
 Press [q] to stop, [?] for help
 size=      96kB time=00:03:03.99 bitrate=   4.3kbits/s speed=2.72e+03x
 video:0kB audio:0kB subtitle:56kB other streams:0kB global headers:1kB
 muxing overhead: 69.999657%
 }}}

 === Platform
 * System: Arch Linux (testing / kde-unstable) x86-64
 * System Language: `zh_TW.UTF-8`
 * Desktop Environment: Plasma 5.17.3 / KDE Frameworks 5.64.0 / Qt 5.14
 * Font: Noto Sans CJK TC
 * `youtube-dl` installed

 == Expected Behavior
 [[Image(https://user-
 images.githubusercontent.com/28441561/69917571-70538280-14a2-11ea-9365-de85e28b82e2.png)]]

 When playing this video with zh_TW subtitle on YouTube Web. (0:14)

 == Actual behavior
 [[Image(https://user-
 images.githubusercontent.com/28441561/69917763-90844100-14a4-11ea-
 99d2-075839fca6f7.png)]]

 When playing this video with the converted ass on mpv. (0:14)

 == (For developers) some reference of styling
 Text Color: https://www.w3.org/TR/webvtt1/#default-text-color
 Cue settings, like alignment, position and etc.:
 https://www.w3.org/TR/webvtt1/#cue-settings

 == Sample File
 * [https://github.com/mpv-player/mpv/files/3908491/AIAIAI-zh-TW-subtitle-
 raw.zip The zh_TW subtitle of that video]

 == Referenced Issues
 * [https://github.com/mpv-player/mpv/issues/7214 GitHub - mpv-player/mpv:
 #7214 wishlist: vtt: support styling]

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8410>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list