Large JPG files loaded slowly

[a.bocharov]

Hello! Sorry for my english: i'm from Russia:)

I have a trouble. Why big JPEG2000 files (about 2000x2000) are very long loaded when I look it in Viewer, and when I view it in Thumbnails? (and XNView is slow down...)

For example. On my PC (ASUS A6000 notebook, Celeron 1500, 712 Mb RAM, WinXP) I tested following programs (JPEG2000 image, ~2000x2000, lossless compressed):

IrfanView: ~in no time (on Thumbnails) and ~4~5 seconds (on View);
ACDSee: ~in no time (on Thumbnails) and in no time (on View) (!!!);
XNView ver. 1.90.3 (, FastStone and some others): ~8 seconds on Thumbnails and View.

(I tried different settings, but situation has not changed in XN )

Also, it would be desirable, that the image is not loading entirely, but loading as in ACDSee (by piecemeal).

Thanks for the answer!

[xnview]

Hello! Sorry for my english: i'm from Russia:)

I have a trouble. Why big JPEG2000 files (about 2000x2000) are very long loaded when I look it in Viewer, and when I view it in Thumbnails? (and XNView is slow down...)

For example. On my PC (ASUS A6000 notebook, Celeron 1500, 712 Mb RAM, WinXP) I tested following programs (JPEG2000 image, ~2000x2000, lossless compressed):

IrfanView: ~in no time (on Thumbnails) and ~4~5 seconds (on View);
ACDSee: ~in no time (on Thumbnails) and in no time (on View) (!!!);
XNView ver. 1.90.3 (, FastStone and some others): ~8 seconds on Thumbnails and View.

(I tried different settings, but situation has not changed in XN )

Also, it would be desirable, that the image is not loading entirely, but loading as in ACDSee (by piecemeal).

Thanks for the answer!

Perhaps you must try the jpeg2000 plugin from luratech (plugins package)

[a.bocharov]

Thanks, Pierre!

It little bit better with LuraWave JPG2000 plugin: instead of 7~8 sec loading time became some seconds. But... I don't think, why JPEG2000 thumbnails, in comparison with other graphics viewer (I speak about Irfan and ACDSee), are building so long!

And I don't think, why junky ACDSee get fantasy speed in thumbnailing pictures of any dimensions? It would be desirable, that just XNView called the Fastest Browser in the world .

Do you know, what else JPG2000-plug-ins I can use with XNView?

[xnview]

Thanks, Pierre!

It little bit better with LuraWave JPG2000 plugin: instead of 7~8 sec loading time became some seconds. But... I don't think, why JPEG2000 thumbnails, in comparison with other graphics viewer (I speak about Irfan and ACDSee), are building so long!

And I don't think, why junky ACDSee get fantasy speed in thumbnailing pictures of any dimensions? It would be desirable, that just XNView called the Fastest Browser in the world .

Do you know, what else JPG2000-plug-ins I can use with XNView?

Ok, could you send me a file, please?

[foxyshadis]

And I don't think, why junky ACDSee get fantasy speed in thumbnailing pictures of any dimensions? It would be desirable, that just XNView called the Fastest Browser in the world .

Do you know, what else JPG2000-plug-ins I can use with XNView?

ACDSee has a number of methods to significantly speed up thumbnailing images. (Whether they're evil hacks or not depends on your point of view.) JPEG2000 at its most basic is a progressive format with several smaller scan levels - at each level it fills in the canvas, resizes to 2x, and starts filling again with the difference. So you can use only a level up to the size you need, typically the first or second level, and just bypass all the rest for a speedup. DjVu and some other wavelet formats work the same way.

Jpeg can work similarly, but only in the special case of the full image being at least 8 times the size of the preview/thumb, by using only AC coefficients. (Well, it might work at 6x with a small resize, doubt anyone would notice.) It works best in progressive jpegs, but it'll be only marginally slower in baseline/optimized mode, because you still bypass the DCT. This would work for HDP as well.

Xnview doesn't use either of these tricks, it just decodes the image to full size and shrinks it from there. I hope it might someday!

(If you didn't really want to know why, well, sorry...)

[a.bocharov]

I kind of thought so. Thanks. Ehen! There are no advanced algorithms in XNView.

May be, it is not necessary for anybody, except for me?

However, some "advanced" will move XNView on top:
- when loading large JPEG2000, I cannot terminate loading on ESC!
- when I turn in "High Quality Zoom" on enlarge, XN very slow down at the big zooming (on any images, any formats, any dimensions)! Logically to resample only that visible part (!) of Image? Why XN does it with ALL image?
- XNView-Viewer wants INSTANT image showing, that is image must showing synchronously with loading. It is a good idea, isn't it? It may "hide" algorithmics imperfection.

---
What is more, XNView, in my opinion, don't work correctly with DJVU. In all versions, include current, my DJVU files are not loaded (or loaded only first page), but its very vell in IrfanView?? Is it a bug? (I can send you a file)

[foxyshadis]

Slow zoom - totally agreed, above 500k pixels it's painful, to say nothing of 15Gpix zoom I sometimes want (good way to crash it). OTOH, above 8x the HQ serves zero purpose, it's questionable even at 4x whether it's any better than simple point resize. Someone will always want it, no matter how useless, though. Feedback has shown that people want fullscreen HQ zoom at least to some degree beyond fit-to-screen, so letting it go to 200% or 300% of screen size isn't a bad idea, since the basic idea is still sound.

As for windowed vs full image, that's a hard decision to make, because scrolling around is such a common follow-up to zooming. Other software either gets laggy or cuts the rest of the picture off until you stop scrolling. My personal feeling is that a good compromise would be to extend the zoom window a half a screen or a full screen in each direction, sometimes slow but not unbearable; without infinite pan or a zoom window, that's as far as you could go on one mouse drag anyway. (Oh, how I'd love a photoshop-style zoom window.)

(Just thinking out loud here.)

If we keep bugging Pierre, xnview will eventually have these kind of optimizations, hopefully before 16-core, 10GHz cpus make them obselete.

[JohnFredC]

Similar topic here.