Why does Irfanview take so long time when scrolling jpg:s

[jasifil]

I have a problem which is annoying me. When I scroll (with mousewheel or next/previous-buttons) edited jpg:s it takes 5-10 times longer than the time it takes to scroll unedited files. Even my raw-files (Nef) takes much less time to scroll. My raw-files have a size of about 15-20 MB while my edited jpg:s have a size of about 8-10 MB.

I am using version 4.25 and Windows 7.

Could anyone please tell me what´s wrong in my setup?

[Bhikkhu Pesala]

Size on disk is not important — it is size in memory that matters. You can find the details on the File Information dialogue. How long a file takes to load and display will depend on how long it takes to decompress and how big it is memory.

RAW NEF File
4.97 MB (5,207,669 Bytes) on disk, 17.21 MB (18,048,040 Bytes) in memory, loaded in 516 milliseconds

The same image as JPG
178.53 KB (182,811 Bytes) on disk, 17.21 MB (18,048,040 Bytes) in memory, loaded in 562 milliseconds

So, if your compared RAW and JPG files that were similar sizes on disk, the JPG file would be much bigger in memory, and take much longer to laod — it would also have a lot more detail, i.e. more pixels.

[jasifil]

Thanks for your reply. I did the same test. My results are as follows.

RAW Nef file
14.76 MB, 34.48 MB in memory, loaded in 1326 milliseconds

The same pic but now edited and jpg
9.02 MB, 25.74 MB in memory, loaded in 4322 milliseconds.

Jpg does not take 5-10 times longer but still much too long time in my opinion.

[Bhikkhu Pesala]

I'm wondering why your JPG is so big — 9 Mbytes does not seem possible. Note the size of mine is in Kilobytes. Even if I use the highest quality and disable chroma subsampling it is still only about 2 Mbytes.

What kind of hardware are you using — my 3 year-old PC is pretty slow, but the load times are very much faster than you're reporting.

AMD-64 3500 Ghz with 1 Gbyte of RAM and onboard GeForce 6100 graphics chip.

Perhaps the problem is that you're using fit to window and resample zooming. Check in View, display options.

[jasifil]

My jpg:s become that big since I save them in best possible quality after editing them in Photoshop. Straight out of camera the jpg:s are about 4-5 MB each with mid-quality and the NEF:s are about 15-20 MB each in the compressed mode. Uncompressed they become 25-30 MB each.

My computer hosts an Intel Pentium 4, 3600 Mhz with 3 GB RAM. Harddrive 2x500 GB in raid 0. Graphic board ATI X850XT.

I am thinking if it is possible that Irfanview contains a bug or if the behavior is normal? In my opinion it is rather irritating that the load-time is so long for my jpg:s.

[Bhikkhu Pesala]

My test NEF file is slightly smaller than yours, but I cannot get load times much more than 500 milliiseconds.

If you want to send a link to one of your JPG images I will see how long it takes to load here.

You could also try saving the files from IrfanView and see if the load time is the same as the ones saved from PhotoShop. Only something like wavelet compression would explain the 3x difference between loading NEF and JPG images. Are you saving in JPEG 2000 format?

[jasifil]

Please try to load my file. Download it here.

7,89 MB, 34,48 MB on disk, loaded in 4664 milliseconds.

[Bhikkhu Pesala]

Got it.

Loaded first time in 1047 milliseconds, second time in 875 milliseconds

Saved at highest quality from IrfanView

Loaded first time in 734 milliseconds, second time in 734 milliseconds

[jasifil]

I downloaded the pic to My computer at work. On this machine I use XP and Irfanview 3.99. Loaded in 750 milliseconds the first time. Could it be something wrong in my computer-setup at home?

[Bhikkhu Pesala]

Its not the IrfanView version — times are the same here for 3.97.

It may be that your P4 PC is slow, or it may be the RAID drive setup you're using has a slow data transfer rate.

I thought of a reason why NEF files load much faster than JPG. Check the setting in properties miscellaneous and see if IrfanView is set to load a preview image. Also check the pixel size in the status line. Obviously, half sized preview images will load much faster.

However, that won't explain why your hardware is slow. Drive fragmentation can also affect data transfer rate, so try running some disk mainenance tools.

[jasifil]

I haven´t experienced this kind of problems earlier with the same hardware. One possibility could be Win 7 but I´m not sure. I thin I´m going to try downgrading Irfanview and see if there will be any difference in loadingtime.

[Laurent]

Hi Jan,

Here it took 594 ms to load your image (double click from Windows Explorer).

Try with a JPEG directly from your D700 to see if it is loaded faster. If there is no significant difference, probably your system is slow.

Laurent