[Image-SIG] Workarounds for MemoryErrors

[Gregor Kopka]

Hello,

to process a ~ 25GB (uncompressed image data) you are afaik out of luck 
with PIL.
Only chance would be to use a fairly recent 64 bit OS with 64 bit python 
binaries (some custom patches /might/ be needed though) and give it a 
hefty amount of swapspace (at least eight times main memory) to fit the 
image into virtual memory, but then you would wait for the disk for 
hours (at best) or - depending on the operations you want to perform - 
way longer.

The question of how to open the resulting image also arises...

Since you didn't give any details on what you need as output format, or 
the operations you want to perform on the image while in memory (or 
whereever it might be at that point) it's hard to give any better clues.

Regards,

Gregor

B. Bogart schrieb:
> Hello all,
>
> I want to create a very large RGBA image (96000x72000 pixels).
>
> I have 4GB of RAM.
>
> Is there an easy way of getting around this error by having PIL only
> allocate one section of the image at a time?
>
> If PIL does not have any internal trick to work with large images then
> I'll have to make 4+ smaller images one at a time, but then I'm not sure
> how I could combine them without needing to allocate a memory chunk for
> the whole image.
>
> Otherwise I suppose I'll have to try with some other language, perhaps
> C/SDL, though a quick calculation seems to show that such a large RGBA
> image is just unworkable. Is there some way of using disk space rather
> than memory? Does not matter if it is slow, just that it is possible!
>
> Any advice?
>
> Thanks,
> B.
> _______________________________________________
> Image-SIG maillist  -  Image-SIG at python.org
> http://mail.python.org/mailman/listinfo/image-sig
>
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