[Matroska-general] Re: VobSub SSA subtitles in matroska

Yusaku yusaku at anime.cz
Fri Dec 26 09:49:24 CET 2003


> > Disadvantages:
> > - No animations, karaoke etc. (forget ASS)
> You should be able to render ASS at 24fps (or whatever framerate) for
importing
> as VobSub.  It would take a lot more space, but it would certainly be
possible.
> If someone made a highspeed lossless codec that supported P frames, it
wouldn't
> even take up that much space.  CorePNG wouldn't be an option for rendered
ASS as
> it decodes much to slowly.  But, someone could probably make a version of
> Huffyuv that used diffs for P frames, just like CorePNG does.

Yeah - unfortunatelly my app just converts already rendered bitmap from
MaestroSBT, which doesn't support ASS. But integrating it to TextSub code
sounds really nice - I am just scared of the DShow part, as it would
probably need a new pins for image (not vobsub) subs etc.

Also, starting from next year (not too far now...) the bloody Unisys GIF LZW
patent will finally become a history - and as GIF decoding is a LOT faster
than PNG, it could be done this way...

> > Notes: Mosu: could you losen up a little on the MPEG2 parsing? VobSub
will
> > not complain about wrong contents of PS packets, but mkvmerge does
complain
> > about "Unsupported MPEG level" or something like that...
>
> That should be a warning to let the user know there was something not
right with
> the data stream.  It might still be playable, but it is important to let
people
> know about potential issues.

I would not say anything if that would be the case, unfortunately now it
rejects all packets which are not MPEG2 compatible (=for quite some time all
I got was empty VobSub stream)

Yusaku






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