[FFmpeg-devel] [rfc] qualification task: SSE2 IDCT

[Michael Niedermayer]

On Sun, Mar 30, 2008 at 02:25:15PM +0100, Balatoni Denes wrote:
[...]
> Also if Alexander gets skal to donate his code under LGPL, will it satisfy the 
> qualification task requirement, as skal's idct iirc is in fact very similar 
> to app note 922/945 ? :)

Is skals idct faster/slower/same speed/unknown relative to ap* ?

My original idea for this qualification was to have a AP922/945 SSE2 idct
which combines all optimizations from all existing such IDCTs. So the
question about any single one being ok is not awnserable. The code has to
be compared to see if there are any further improvments possible.
Also the output must be binary identical to an existing IDCT
(to minimize the issues with idct drift between the ever growing number
of idcts)
Its a little mystery to me why alex apparently thought this was an easy task.

Now iam perfectly fine with a simple SSE2 idct one. This would at least
skip the binary identical output problem and the work for me comparing
it against other IDCTs. OTOH its harder as there is no existing SSE2 code
to base ones work on ...

Theres also AMD who have promissed to implement 2 things for us,
they are (since months) working on a SSE float aan dct. I think they might
be happy if the second task would be a AP945/922 SSE2 IDCT as they already
have some code for that.

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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