[sldev] OpenJPEG vs KDU

Dirk Moerenhout blakar at gmail.com
Wed Jun 27 13:19:58 PDT 2007


Great, the work of you and Callum combined brings us probably already
very close to the target. From LL's point of view it's clear: as soon
as OpenJPEG competes on speed with KDU, KDU can be replaced. If Callum
posts the current status of his patch we can see where we are in terms
of beating KDU.

Do you by any chance have already coded up something that calls KDU
thru llkdu? I'm not exactly planning to pay 250AU$ to get the library
:)

Dirk aka Blakar Ogre

On 6/27/07, Dzonatas <dzonatas at dzonux.net> wrote:
> Some of the patches have already been applied to the main OpenJPEG
> repository.  They provide about a 2x speed-up.
>
> I started work on the Floating Point/SSE and posted the patch here.
> Callum has taken over to finish up that code with merges into the T1
> work that was done.
>
> The Floating Point/SSE, as it was, provided about anywhere from 2x to
> 20x speed-up, which set it closely behind KDU.
>
> I bet that OpenJPEG could be made to go faster than KDU under the
> terrible threads conditions (cache pollution) of Second Life. KDU was
> not designed to handle such conditions.
>
> Dirk Moerenhout wrote:
> > Have these patches been submitted to the OpenJPEG maintainers? Do you
> > think there would be any resistance from them in getting them applied?
> > Given I'm located very near to them I wouldn't mind lending a hand
> > when it comes to communication.
> >
> > Where can I get these patches?
> >
> > Dirk aka Blakar Ogre
> >
> > On 6/27/07, Callum Lerwick <seg at haxxed.com> wrote:
> >> On Wed, 2007-06-27 at 01:39 +0200, Dirk Moerenhout wrote:
> >> > Ok, in light of VWR-866 I'm wondering what it would take for OpenJPEG
> >> > to replace KDU. I've heard that KDU would be faster. Anybody has an
> >> > idea on how much? I've build OpenJPEG 1.2 with VS2005 and did a quick
> >> > check using CodeAnalyst. A few minutes after my first run I got a 0.5%
> >> > benefit with 1 minor change. That may sound minor but given the
> >> > simplicity of the change I guess some real effort would give us quite
> >> > a bit more.
> >>
> >> I've revived Dzonatas DWT vectorization patch, which results in a
> >> significant speedup. Especially combined with my T1
> >> vectorization/cleanup patch which can pass floating point data direct
> >> from T1 to DWT.
> >>
> >> I've got a bunch of patches lined up I really need to finish off and
> >> submit...
> >>
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> --
> Power to Change the Void
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