no bug management of "ECW" format is slow

[luiscuadrado123]

Hello!!!! first of all.. I LOVE THIS SOFTWARE. THANKS FOR THE CREATORS!!

Excuse my level of English, I speak Spanish and I am using the google translator to communicate this.

I'm not sure if this is a bug or not, but I think it can be improved.

I always deal with images in the ECW format and they are usually large images (greater than 150mb at least). I even get to handle images of the order of 1gb per file.

Specialized GIS programs can view and manipulate this image format very quickly. Not so my dear IrfanView, which takes many seconds (or even a minute) to display the image or if the file is too big I get a "DECODE ERROR" and it can't display it.

Just to do my bit, I want to share a VERY SMALL ECW file viewer (2,2mb size on portable version) whose performance when opening and moving around the image is really impressive. It is even faster than large specialized GIS programs.

The program is called ImageVisu and its website is this:

http://geovisu.free.fr/imagvisu/english/

Maybe, just maybe, you guys can do some sort of reverse technology to the program to see how it works internally and try to copy it.

It would be great to have all the benefits of functions that IrfanView offers with the performance of ImageVisu, since the latter only serves to quickly display the image, but I can't do anything else about it.

If you find it necessary, I'll share a download link for a large example image so you can test it. The image is my own and I upload it to my MEGA account:

EDIT: LINK CORRECTED

https://mega.nz/file/RcNGlT6a#N4PRPjkBZpeaj-vuxsG-RCHQqYnXCkpfsYXQ7ROgmNM

[Bhikkhu Pesala]

We need a password to download the image for testing.

See this earlier thread.

[luiscuadrado123]

sorry by the pass of the link

the correct one is this:

https://mega.nz/file/RcNGlT6a#N4PRPjkBZpeaj-vuxsG-RCHQqYnXCkpfsYXQ7ROgmNM

[luiscuadrado123]

We need a password to download the image for testing.

See this earlier thread.

i have read this time ago... but i don't understand why in the same computer, with the same hardware, the same big image file can't be opened by one software (ImageVisu) and can't be opened by irfanview..

I don't have high computer skills but logic tells me that there must be something in the treatment of the file type that can be optimized. I bring as a contribution this simple free software that I found, that maybe you can use the same library to read/write the ecw format??

[luiscuadrado123]

Imgvisu can read ECW files instantly, even if the file size is 1 or 2gb size.

[Bhikkhu Pesala]

Decode error, because there is not sufficient memory to hold the decoded image.

[JendaLinda]

I suppose IrfanView is trying to load the entire image in memory but the specialized software can load just the part of the image which is viewed.

[luiscuadrado123]

I suppose IrfanView is trying to load the entire image in memory but the specialized software can load just the part of the image which is viewed.

makes sense

but notice that the program that I cite as an example (which I insist weighs less than 2.5mb) opens the "visually complete" image instantly (I put it in quotes because internally I don't know what it does to be able to visualize the complete image so quickly, maybe maybe it shows you a "preview" of it in low quality, I don't know)?

[luiscuadrado123]

Decode error, because there is not sufficient memory to hold the decoded image.

ok.. thanks for that.

but... there is a solution? maybe using the same way that the ImgVisu programm uses to view the images?

i insist... I don't know how, just thinking out the box

[JendaLinda]

That would require fundamental changes in the internal workings of IrfanView.

I'm not familiar with ECW format, but I suppose it allows to quickly view the entire image in low resolution, before zooming in to the details.

[aisle^]

i think there is not sufficient memory to hold the decoded image

[luiscuadrado123]

i think there is not sufficient memory to hold the decoded image

in the actual internal workings of IrfanView, YES.

but may exist other ways to view the same image like other softwares properly.

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OK will keep using other viewer to this file type and using irfan to the normal images