Out of memory error at very end of stitching process

[Karl Johnson]

Hello,

I have been steadily increasing the size of panoramas which I have been attempting to stitch on my laptop recently, but I seem to have hit a wall at ~8-10 gigapixels. In two instances recently, I have let my computer stitch overnight, and when I return in the morning, the loading bar for stitching is very near to the end (15/16ths or so). However, after stalling at this point for a while, I get an "out of memory" error. This has happened both for a 12 gigapixel panorama (910 photos) and a 9 gigapixel panorama (770 photos) which failed due to this memory error this morning. (I was eventually able to stitch the 12 gigapixel panorama on a much more powerful computer which I have occasional access to at my university)

This error is confusing to me - due to out of memory issues I've experienced in the past (earlier in the stitching process), I've reduced my RAM and VRAM allocated to PTGui well below the physical limits:

My impression was that this could mitigate out of memory issues, as there should be significant margin for any memory leaks/etc. that might result in memory usage beyond the limits specified in the menu above. Additionally, I have plenty of free disk space (~850 GB across two drives) for the temp files generated, which I believe should be plenty for this size of LDR stitch (I expect around 200-300 GB of temp files).

I've searched around on this google group, and the error described in "V12 beta 3 - limit number of images?" seems similar, but it appears as if this was fixed (?). Are there any settings I can adjust to prevent getting out of memory errors? Here are a few more details about the situation:

• I am stitching on fairly slow HDD's, so my stitching speed is currently bottlenecked by disk speed - disk usage is generally pegged during stitching, while CPU and GPU almost never go above 10%.
• In the past two instances of this happening, the stitching process has lasted for 7 and 10 hours, respectively, before failing right at the end.
• When stitching at the machine at my university (128 GB RAM, dual Xeon, nice GPU, designed for image processing), stitching appears to stall at the same point in the loading bar. However, this machine is actually able to finish the stitching process - I'm not sure how long the stitching is stalled at that point in the loading bar, as I usually leave the computer alone overnight once it gets to this point.

While I'm perfectly able to stitch my personal panoramas on this university computer right now, I won't have access to that computer forever and I'd like to be able to stitch these types of panoramas on my own machine. Do I really need to upgrade my computer, or is there a bug/setting that's responsible for these out of memory errors?

Thanks,

Karl Johnson

[Karl Johnson]

Quick additional note: this is on PTGui Pro 11.30.

[PTGui Support]

Hi Karl,

Especially for large multi gigapixel images it's difficult to confine
PTGui to exactly the configured RAM limit. PTGui will swap image data to
disk but there are always some data structures in memory. The operating
system should be able to handle this by swapping between RAM and disk.

So I think it's just a matter of increasing the page file size in
Windows. Could you try that? You can find instructions by googling.

BTW using an SSD for temp files instead of a spinning hard drive may
save hours of time.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

On 28/02/2021 17:24, Karl Johnson wrote:
> Hello,
>
> I have been steadily increasing the size of panoramas which I have been
> attempting to stitch on my laptop recently, but I seem to have hit a
> wall at ~8-10 gigapixels. In two instances recently, I have let my
> computer stitch overnight, and when I return in the morning, the loading
> bar for stitching is very near to the end (15/16ths or so). However,
> after stalling at this point for a while, I get an "out of memory"
> error. This has happened both for a 12 gigapixel

> <http://ka.rljohnson.net/photos/Panoramas/20210223/> panorama (910

> photos) and a 9 gigapixel panorama (770 photos) which failed due to this
> memory error this morning. (I was eventually able to stitch the 12
> gigapixel panorama on a much more powerful computer which I have
> occasional access to at my university)
>
> This error is confusing to me - due to out of memory issues I've
> experienced in the past (earlier in the stitching process), I've reduced
> my RAM and VRAM allocated to PTGui well below the physical limits:

> Screenshot 2021-02-28 085948.jpg
> My impression was that this could mitigate out of memory issues, as
> there should be significant margin for any memory leaks/etc. that might
> result in memory usage beyond the limits specified in the menu above.
> Additionally, I have plenty of free disk space (~850 GB across two
> drives) for the temp files generated, which I believe should be plenty
> for this size of LDR stitch (I expect around 200-300 GB of temp files).
> I've searched around on this google group, and the error described in
> "V12 beta 3 - limit number of images?" seems similar, but it appears as
> if this was fixed (?). Are there any settings I can adjust to prevent
> getting out of memory errors? Here are a few more details about the
> situation:
>

> * I am stitching on fairly slow HDD's, so my stitching speed is

> currently bottlenecked by disk speed - disk usage is generally
> pegged during stitching, while CPU and GPU almost never go above 10%.

> * In the past two instances of this happening, the stitching process

> has lasted for 7 and 10 hours, respectively, before failing right at
> the end.

> * When stitching at the machine at my university (128 GB RAM, dual

> Xeon, nice GPU, designed for image processing), stitching appears to
> stall at the same point in the loading bar. However, this machine is
> actually able to finish the stitching process - I'm not sure how
> long the stitching is stalled at that point in the loading bar, as I
> usually leave the computer alone overnight once it gets to this point.
>
> While I'm perfectly able to stitch my personal panoramas on this
> university computer right now, I won't have access to that computer
> forever and I'd like to be able to stitch these types of panoramas on my
> own machine. Do I really need to upgrade my computer, or is there a
> bug/setting that's responsible for these out of memory errors?
>
> Thanks,
> Karl Johnson
>

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[Karl Johnson]

Thanks for the tip - I'll look into increasing the page file size and see how that helps. I just noticed I only have 10GB or so of free space on my C: drive (which I am not using for temp files) and that could very likely be the cause. I've been eyeing some fast M.2 SSDs for a while for the express purpose of speeding up my stitching (and expanding the size of my C drive) and it looks like it might finally be time to upgrade my computer.

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