[opensource-dev] Openjpeg/KDU the cold hard metrics

Robin Cornelius robin.cornelius at gmail.com
Wed Sep 22 00:55:20 PDT 2010


On Wed, Sep 22, 2010 at 4:01 AM, Sheet Spotter <sheet.spotter at gmail.com> wrote:
> I would love to see Robin's test harness. I would also love to see the
> images that failed with v2.

For the record I cannot give you (or anyone else) the images that
failed, I was testing against a random selection of images pulled from
the texture cache (and yes i know how to get a complete image out the
cache) i wanted it to be a fair cross section of real SL textures not
contrived test cases. I can probably people on an individual basis
UUIDs of failed images but i'm afraid you will have to obtain the
images yourselves I can't just go around distributing SL textures that
are not mine.

Maybe we can make a collection of test textures that we (the
collective we) own, if an individual copyright holder has textures
they can donate we can build a collection of test textures that can be
used for metrics now and in the future.

>
> I started diving into the v2 branch of OpenJPEG a few days ago, after
> research JPEG 2000 for a week. Tackling the bugs from the failed images
> might be a good way to become more familiar with the source code.

I can get full back traces to the offending lines which will be some help.

>
> I posted a very minor patch correcting some simple build problems with the
> DLL version of OpenJPEG V2.
>        http://code.google.com/p/openjpeg/issues/detail?id=40

Yes i had to fix a few issues to get the dll to build, nothing major.

> Thank you for publishing your results, Robin. They are encouraging me to
> continue looking at OpenJPEG v2.

Thanks OJP V2 looks like its worth the effort, so far using it with
the viewer is failing badly. Encode now i've stopped it crashing is
failing causing  a "bake loop of hell" which consumes massive amounts
of CPU time and spams the LL servers with bakes, so bad all around.

As for the test harness, Yes let me tidy it slightly and I'll publish
it, its really simple but i'm lazily working around one issue with
error reporting currently. I also hopefully will have some new data
tonight myself, looks like my results are artificially slow, BUT there
remains a massive difference between KDU and openjpg, possibly worse
than the x4 data i obtained, maybe in the order of x16-x20 slower but
i need to rerun all the tests. This could also explain why SSE was
showing odd results.

Robin


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