[Ffmpeg-devel] [PATCH] Fraps decoder

Roine Gustafsson roine
Fri May 13 21:08:46 CEST 2005


On May 13, 2005, at 7:51 PM, Mike Melanson wrote:
> 	What have you figured out about v2? Are the frames constant- or 
> variably-sized? Are you reverse engineering the binary or visually 
> inspecting the compressed video data?

No, they're not constant size. I haven't looked at the dll, only the 
data.
There seems to be a frequency table stored before each plane. It's 256 
frequencies that has the 'bell' form; therefore I'm suspecting it's a 
simple left-difference or similar.
I tried interpreting the data planes as being canonical Huffman coded 
difference, with the frequencies from the table, but I've not gotten 
anything reasonable out from that.

I think the 2nd and 3rd planes are smaller so it might be yuv420.

Anyway, the files I wanted  to watch (Konoko_*) were all v0, so my 
mission is completed :)

> 	"fps1" is currently the top search string driving people to my 
> multimedia.cx site. This work should be useful.

Cool.

   /Roine





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