idx / sub specifications

[kitsaros2000]

Can someone help me to find the tecnhical specs of the vobsub ?
Is someware any kind of documentation about this ?

Thx and have a nice xmas ! :D

[unmei]

Well, the .sub file is basicly a mpeg-2 program stream containing private PES packets which then contain the SPU (sub picture unit) frames.
PS and PES are specified in ISO 13818-1, SPUs are AFAIK not specified in the mpeg-2 spec, but i think they are relatively low complexity, basicly RLE encoded paletted bitmaps and you should be able to get info on that by googling for spu or mpeg subpictrue or something similar. For a start try these sites http://sam.zoy.org/writings/dvd/subtitles/ and http://dvd.sourceforge.net/spu_notes. For more you might want to join mpucoder's site http://mpucoder.com/DVD/

[gircobain]

spumux's source code, included in dvdauthor pack, may give you some clue as well

http://dvdauthor.sourceforge.net

[kitsaros2000]

i already made txt2sup tool and i know the sup format. I cant understand the relationship sup - sub(vobsub) since i opened with an sub with an hex editor and the structure was different from the sup file.

[unmei]

A sup file is the raw SPU data.
The vobsubs have this data packed into mpeg. You have the SPU data chopped up put into mpeg PES packets of 2048 byte and these again are packed into PS packets (or was it the other way round :confused: ). In short you need to have a mpeg stream muxer/demuxer to operate on it, at least a vaery primitive one that can get stuff out of the packs or put it into them even if it doesn't know any more...