[FFmpeg-devel] DVD subtitles

Måns Rullgård mans
Wed Feb 27 14:49:37 CET 2008

Erik Slagter wrote:
> Hi, it's me again ;-)
> As the AVFilter framework got merged recently, it looks to me a perfect
> basis for a hardsub filter, it looks like there doesn't exist something
> like that yet(?). Although I am ehrm... not too enthusiastic about
> hardcoding subtitles in video, encoding to mp4 with subtitles and
> playing on non-mplayer "equipment" seems to leave me no choice :-/
> Anyway for this to work I'd reckon all (DVD) subtitles need to be
> detected correctly. At this moment it doesn't. In the past I had a
> workaround, forcing the probe routines to dive further into the file
> than it normally does, but it seems that this knob (#define) is no
> longer used.
> So, my question: is there a (known) method/workaround to have
> ffmpeg/libav* detect all DVD subtitles in a vob? Or is this simply a
> bug/regression?

Without the IFO files, the only way to find all subtitle streams is to
read the entire file.  It is not uncommon for a DVD subtitle stream
to have its first packet an hour or more into the film.  This is
typically the case for a mostly English film with a few lines in some
other language.

Even if you do find the subtitle streams, you are still missing the
palettes.  Supporting subtitles in raw vob files will always be a
bit hit or miss.  There's only so much you can do without all the

M?ns Rullg?rd
mans at mansr.com

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