[FFmpeg-devel] DVD subtitles

Erik Slagter erik
Wed Feb 27 15:13:11 CET 2008

M?ns Rullg?rd wrote:

>> 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
> data.

Reading separate IFO files of course would be The Right Thing To Do, but 
from past experience I've learned there isn't much interest in (DVD) 
subtitling from most ffmpeg developers. Also the whole of libav* and 
ffmpeg is really too complex for the amount of spare time I have, so 
there won't be a "patch" from me either (libav* opening "other" files 
from disk, I've just read the thread on mov..., ouch!)

So, I'd really settle with some knob that indeed allows to scan an 
arbitrary amount of a vob file for subtitles. If the colours are 
incorrect, that's something I can live with.

BTW We're talking of English/American DVD's subtitled in Dutch. That 
means a subtitle generally comes up within only a few seconds after each 
chapter change. It's not like audiodubbed movies with in total two 
forced subs.

More information about the ffmpeg-devel mailing list