[Scummvm-devel] DXA file format for videos

Jonathan Gray jsg at goblin.cx
Tue Apr 25 05:15:06 CEST 2006

On Tue, Apr 25, 2006 at 01:32:46PM +0200, Max Horn wrote:
> On Di, April 25, 2006 13:24, Gregory Montoir wrote:
> > Travis Howell wrote:
> >>
> >> So I think it would be a good idea to use the DXA file format for video
> >> playback in all games supported by ScummVM.  The DXA file format would
> >>
> >
> > As a prerequisite, it might good to know what epic-interactive/rune-soft
> > think of this idea (that's more or less part of their technology,
> > afterall).
> >
> > I don't think the .DXA file format has been re-used since Feeble Files
> > and Software Tycoon ; but still, it would be best to have some kind of
> > authorization.
> >
> Considering the extreme simplicity of the scheme (XORing a frame with the
> previous frame, the compressing the result using zlib), I am pretty sure
> there is little they could do against it. For the frame xoring, there is
> definitely prior art. So is there for compressing the result. And using
> zlib likely isn't turning this into an "original" protecable technology.
> But of course IANAL.
> We certainly can ask them out of courtesy, but if done, it should be
> executed in such a way that makes it *very* clear that it's likely
> unprotected technology anyway. Else, the standard reaction of many
> companies is to deny such requests, or only agree with them under certain
> conditions.
> Anyway, we might want to change the name from DXA to something of our own,
> to make it look less like we are copying some advanced video compression
> scheme. zXOR, ZOR, XORz, ZXC (zlib xor compression) etc., many
> possibilities up there ;-).
> Cheers,
> Max

There are several openly documented lossless video codecs out
there if that is what is being considered.

ie HuffYUV http://wiki.multimedia.cx/index.php?title=HuffYUV

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