opening large JPG pictures

[dschallock]

I have a fairly beefed up Amiga 3000 Tower. 060 - Picasso IV - 86 Megs of fast ram - etc.

I have been taking digital photographs and transferring to my Amiga to manipulate in ImageFX4.5

I took a panographic picture with my iphone and the final jpg was like 2000x6000 pixels or something like that. The JPG size was 17 megs. When I try to open it, it tells me there is not enough memory.

I tried Imagefx, Adpro, ArtEffect4 and all gave errors.

Is this some kind of issue where a 17meg Jpg needs 10times the memory to open or something? Is more Ram the solution or is there some other limitation that does not allow this on an Amiga?

Thanks.

[robinsonb5]

Have you tried ImageStudio? It has a disk-buffering system so it can deal with images larger than available memory.

[twitek]

Originally Posted by dschallock

Is this some kind of issue where a 17meg Jpg needs 10times the memory to open or something?

Not 10 times more memory, but it needs to decode the JPG format to raw pixels, which is around 46MB, then convert it to your display size of 1280x1024x24bit, which is another 3.75MB.


I don't know if more memory will help, because you should already have enough. So it's probably a limitation of the software.
If i remember correctly, even PC JPG viewers could not display JPGs larger than 2048px on one side for a long time. Must be some C-programming thing.

[dschallock]

Appreciate the advice.
Actually, since you mentioned that imagestudio uses virtual memory I think Imagefx4.5 also has an option for that.
Maybe I should just try turning that up and see if that helps too.

[source]

Under prefs in imageFX there is an option for virtural memory. In there you set it to use virtual mem if needed. then you specify the amount of true memory that you want to use before it buffers to the hard drive (directory that you specify). I do know that imageFX does have issues with large image sizes. Save your projects often and don't over write previous files until you know that the more recent edits were ok and saved.

[Thomas Richter]

Originally Posted by dschallock

I took a panographic picture with my iphone and the final jpg was like 2000x6000 pixels or something like that.


Is this some kind of issue where a 17meg Jpg needs 10times the memory to open or something? Is more Ram the solution or is there some other limitation that does not allow this on an Amiga?

This is simply not practical. An Amiga, even a 68060, does not enough computing resources to render today's images, even if it is only JPEG, in a time that would make this convenient or practical.


With your average badly implemented JPEG decoder, I would expect that the memory requirement for 2000x6000 pixels is approximately 3x2000x6000x4 bytes, thus approximaley 137MB. One can with only a small fraction of that if the input file uses the progressive scan only, ~570KB only, but this requires a smarter implementation, and I doubt anyone back then had done that and just copied the (not so smart) IJG code.

[ProfPlum]

And here I am foolishly trying to view a 4k picture not realizing the memory requirements.
Thank-you Thomas.

[gdonner]

I can only imagine how slow 4k can be even on a decently beefy PC (which I have). It takes a lot of RAM and bandwidth at that resolution... not to mention gaming at that screen res. 8-O

I'm actually pretty impressed with how well an '060 Zorro III Amiga and a good RTG card can still fare considering its age. Still some work to do, but there are some nice things on the way (e.g. OS 3.2 and Warp 3060/4060) that will give the Amiga a nice boost software -and- hardware-wise. My hat's off to all those who have put in a great deal of work for both those projects.

[meynaf]

Just attempted to show a 5760x3240 baseline JPG i've found on the net, under winuae jit and my own picture viewer -- for the fun.
I needed to configure 32MB of 32-bit chipmem, something real miggies can't do.
However fastmem requirement was way under 4MB. Took approx 5 secs, including HAM8 rendering (i have a 6 years old i7 laptop).
So memory requirements of showing a jpeg image aren't so bad.