[Matroska-devel] CorePNG to store still images ?

Steve Lhomme steve.lhomme at free.fr
Tue Oct 5 15:27:08 CEST 2004

Hi Jory,

Toff's DvdMenuXtractor used to extract still images from a DVD to BMP 
files. The advantage is that when you compress the images, you can save 
some space. In the other hand BMP is not compressed and it can't be 
muxed into Matroska.

The problem here is that DVD cells can be in still format at anytime 
(maybe not anytime but theoretically they can). So we need to integrate 
it into the stream. We have 2 options :

- encode the still cells as continuous cells. Hopefully MPEG2 readers 
can output the data as one or more frame. One frame with a long duration 
would be nice, but I doubt it will happen :(

- encode the stills as CorePNG and switch between the main and CorePNG 
tracks when needed

I think the cleanest way is to use CorePNG, but that implies using a 
"sub-track" for each possible DVD video track (ie angle).

robUx4 on blog <http://robux4.blogspot.com/>

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