Legacy ImageMagick Discussions Archive

Sorry to keep reporting this.

I am still getting very slow conversions from jpg to gif after IM 6.4.1-3 for both Q16 and Q16 HDRI

convert logo: logo.jpg

6.4.1-3 Q16 non-HDRI

time convert logo.jpg logo.png

real 0m0.348s
user 0m0.270s
sys 0m0.043s


6.4.1-3 Q16 HDRI

time convert logo.jpg logo.png

real 0m0.339s
user 0m0.270s
sys 0m0.042s


6.4.1-4 Q16 HDRI
time convert logo.jpg logo.gif

real 1m3.886s
user 1m2.246s
sys 0m0.675s


6.4.1-5 Q16 non-HDRI

time convert logo.jpg logo.gif

real 1m5.445s
user 1m2.386s
sys 0m0.688s


6.4.1-5 Q16 HDRI

time convert logo.jpg logo.gif

real 1m4.148s
user 1m2.091s
sys 0m0.657s


I am on Mac OSX Tiger PPC

> Sorry to keep reporting this.

We've been swamped with refactoring ImageMagick for dealing with importing / exporting pixels and supporting OpenMP. That's done now and we can refocus on other problems. Give us a few days to investigate and we will hopefully have a fix for this problem.

Thanks. Whenever you can get to it.

By the way, did anyone bite-off on trying to speed up -fx?

The ImageMagick developers sped it up significantly but only if you have a quad-core processor. There are few additional opportunities for speed-ups other than creating a postfix stack and interpreting the stack. Even then we can only see about a 40% speed-up. Some FX expressions could be optimized but either of these options require the skill of a wizard developer which are difficult to find and engage. The most promising speed-up is a command line program that converts the FX expression to an ImageMagick filter that can be compiled and loaded. We intend to develop this program but it may be years before we get to it...

HDRI is floating point intensive. Does you computer perform floating point in software or hardware?

It took 8 seconds on our 3Ghz Intel chip to convert logo.jpg to logo.gif with HDRI Q16 ImageMagick.

Actually, I have no idea. But the point is that under IM 6.4.1-3 HDRI it only took 0.4 sec, but under IM 6.4.1-4 and 6.4.1-5 either Q16 or Q16-HDRI, it took over a minute. See timings above. So something has changed for the worse since 6.4.1-3