Black Vertical Line After Resampling

[KMinOZ]

I just upgraded to 4.10 after noticing in a panorama viewer that I get a black vertical line when resampling a JPG image from 13766 x 6883 pixels to 3000 x 1500 pixels.

The problem persisted in 4.10

After changing the background in Irfanview to white, I could confirm that this line only appears after resizing, the original does not have a black border.

Would be great if this could be fixed in the next release. Needless to say that I am otherwise a very happy user of this fantastic program that can easily be copied to a memory stick to be available wherever I am.

[Bhikkhu Pesala]

I can reproduce the problem with a new image of those dimensions, but not with one of 15,000 by 7,500. It could be a rounding error.

I wonder what is so special about the numbers 13766 and 6883?

[Sjef]

It doesn't occur on my system. I produced an image of 13766 x 6883. Than I resized it to 3000 x 1500 pixels. No vertical line here.

[KMinOZ]

I resized a lot of 2:1 panoramas lately and noticed the error in the panorama viewer. I just picked 13766 and 6883 as an example but the problem also occurs for other dimensions and I agree that it looks like a rounding error.

The dimensions 15000x7500 has the integer 5 as divisor to get to 3000x1500 while 13766x6883 has 4.588666period

I can reproduce the problem with a new image of those dimensions, but not with one of 15,000 by 7,500. It could be a rounding error.

I wonder what is so special about the numbers 13766 and 6883?

[cmichael]

Right side of large images gets corrupted

When I process high-resolution images (ie, panoramas), the right-hand side gets corrupted. Specifically, there's a dark vertical area (stripe) along the right, from top to bottom. The wider the image, the wider the stripe. It starts to become a problem with images around 10K pixels wide. Around 15K or 20K it becomes so noticable as to ruin the image. I haven't counted the pixel columns but it's probably around 50. This is 100% repeatable. I'm using v4.10.

[ChuckE]

Really? I just created a 15,800 pixel wide image, and I don't see it.

[matera]

M-hmmm...but I think it's not how much IrfanView can handle but how much your computer can handle. I had a lot of trouble trying to generate large fractals before my last upgrade. Fractal Explorer would chug along for a couple of hours, and there was a 60:40 chance that the result would be partially corrupted.

[Bhikkhu Pesala]

I still see this problem with 13766 x 6883 dimensions, but I don't get it with round numbers like resampling a 24,000 x 6,000 pixel image.

[cmichael]

Test images

Here are some test images to reproduce the problem. The bigger file is 27,000 pixels across (a 360-degree panorama image). I compressed the heck out of it to get around the max file length restriction of attachments for this forum. The second file was produced by Irfanview. It has the black vertical line on the right side, as I described. Once again the forum uploader gave me trouble because it considers it an "attached thumbnail" rather than an "Attached file" as I intended it to be. You can view it by clicking on the thumbnail. I made this using:
v4.10
Batch Mode
JPG compression: 65
Advanced: Resize, set long side to: 1500

Attached is the .ini file I used. The forum uploader kept saying "invalid file" so I had to rename it to a .txt. You'll need to rename it back to a ".ini" extension. I'd be curious as to whether others can reproduce the problem. It happens with any large image. The higher resolution, the wider the black bar is. Pls let me know how if you can reproduce it. Good luck,

- Chris

[Bhikkhu Pesala]

The bug has already been confirmed a few times. You can test with a new image of any colour with large dimensions that are not a round number.

A pair of 16 colour PNG images will illustrate the problem, but they are much smaller in file size. The forum doesn't seem to like the 16 colour images though so I have attached them in a zip file.

[jazzman]

FWIW: I tried with your picture and IV 3.98/WinXP Pro and get the black bar alright.

[KMinOZ]

Resampling Bug causing black vertical lines still in V4.20

This problem persists in version 4.20

Just tried to resample a 16372 x 8186 JPEG to 3000 x 1500 and get a black line on the right side again. Unfortunately this bug disqualifies Irfanview from use for resizing of equirectangular panoramas because the resulting black line is very disturbing when viewing 360° panoramas.

I just upgraded to 4.10 after noticing in a panorama viewer that I get a black vertical line when resampling a JPG image from 13766 x 6883 pixels to 3000 x 1500 pixels.

The problem persisted in 4.10

After changing the background in Irfanview to white, I could confirm that this line only appears after resizing, the original does not have a black border.

Would be great if this could be fixed in the next release. Needless to say that I am otherwise a very happy user of this fantastic program that can easily be copied to a memory stick to be available wherever I am.