[FFmpeg-devel] [PATCH] read palette information from extradata for dvd subtitle decoder

elupus elupus
Fri Jan 18 10:42:05 CET 2008

M?ns Rullg?rd <mans <at> mansr.com> writes:

> elupus <elupus <at> ecce.se> writes:
> >
> > I suppose the string based extradata isn't the best way to store that
> > stuff, but seems silly to invent a new format since matroska and vobsub idx
> > files already use this.
> Sensible would be to use the same format as on actual DVDs.

That might get abit complicated. Palette is stored somewhere inside the PGC's 
ifo files. Don't exactly remember where, and providing the full ifo seems very 
much overkill + most of the structure it is part of is of no interest 

What would be of more interest would be to have decoder swallow PCI nav 
packets during decode, so you get all colors needed for dvdplayback. The 
navpackets contain the lookup tables (colormap/alpha) used to index into the 
palette. It would require decoder to output 7 different palettes (3 different 
button colors and select/action palettes for each + the standard clut 
contained in the subtitle).

Now i'm not saying that isn't a good idea, but it would require extending the 
avsubtitle structure to support multiple palettes. Could just add a 
palette_stride parameter so you could split the palette structure in different 


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