XnView Software

win10x64 xnviewmp 1.5.3.

I just tested opening my big image in irfan view: jpeg xl opened ~1.5 times slower than jpeg. In xnview jpeg xl opened ~4 times slower than jpeg!

This should be fixed as fast as possible.

Just look at how it opens an image at 50 or 100 megapixels (or more) in irfan view and xnview, which makes viewing many images in xnview extremely inconvenient and a lack of desire to use it.


Other performance JPEG XL bug:
viewtopic.php?f=62&t=45830
Maybe they correlate. So fixing one cause will fix those two bugs, and maybe more.

could you send me a sample file?

As an example, you can take any full hd image (for example - https://www.pixelstalk.net/wp-content/u ... wnload.jpg), resize it to 14400x8100 (116mp), then save in xnview in jpeg and jpeg xl formats. The jpeg xl will open 4.5 times slower than jpeg. irfan view will open jpeg 2x faster, and jpeg xl 3x faster than xnview. But okay jpeg, it still opens fast enough in xnview, but jpeg xl is too slow, this needs to be fixed.

I have to say that I was comparing xnview to irfanview x32. When I tried the irfanview x64, it was even faster when opening multi-megapixel images. He's surprisingly fast.

Hi,
I made some tests (on win64). Indeed, for huge images, viewing is far longer for jxl than for jpg. Not a big issue in my view because for images with a 'reasonable' size (say up to UHD) viewing is almost instantaneous for both jpg and jxl. According to jxl developers, jxl code is slower to run than jpg code, but this can be compensated by relying on multi-threading (while opening jpg is compelled to run on a single thread). Maybe the issue comes from XnViewMP opens jxl images based on a single-threading ?
cheers
simon

simon wrote: Wed Aug 09, 2023 10:28 amNot a big issue in my view because for images with a 'reasonable' size (say up to UHD) viewing is almost instantaneous for both jpg and jxl.

The uhd resolution is unlikely to be used by those who use jpeg xl. This is not a web format, but a format for taken photos, the resolution of which photographers now have is above 20mp and much higher. Even a smartphone can have 100mp.

Maybe the issue comes from XnViewMP opens jxl images based on a single-threading ?

That's right, xnview only uses one core when decoding. Which is unacceptable for jpeg XL and makes it 6 times slower than fast single-core jpeg libraries.

I've sent you a PM

Thanks to your detailed description I can reproduce the problem.

This problem is supposed to be fixed in XnView MP 1.5.4. Please check and confirm the bug fix here.

Problem is fixed