[FFmpeg-devel] Jpeg2000 decoders comparison

Michael Niedermayer michaelni at gmx.at
Fri Jul 5 00:54:34 CEST 2013

On Thu, Jul 04, 2013 at 10:34:06PM +0200, Nicolas BERTRAND wrote:
> Hi,
> I made some perf test to compare jpeg2000 native deocoder with libopenjpeg.
> I compared the perfs according the number of threads allocated and
> the number of resolutions levels (lowres)
> The strange stuff is: in a many core machine( bi xeon, so 12coresx2)
> , the jpeg2000 decoder is blocled at some fps, and addition of cores
> no help at all. In reverse with libopenjpeg more we add core, more
> the decode is fast.
> In a 4 coresx2 machines. the results are more as expected, and
> native jpeg2000 decoder is faster in almost all cases.
> In native jpeg2000 decoder, code looks somewhere blocked or still
> waiting. But where or how? Right now, no idea why.

A simple way to find out where something is blocked (assuming its
blocked alot) is to use gdb and hit crtl-c and the look at the
backtraces of all the threads

and google points to this:

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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