(Problem) Resolution limit?

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Offline ThunderboltPagoda

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« on: October 28, 2018, 05:13:30 PM »
Hi!

I just wanted to post a JPG with 5600*4200 and 4.829.816 bytes, but it didn't work. Uploading worked, but after clicking the Post button, a white page appeared, and nothing else happened, and the posting didn't show up in my image thread. Is there a resolution limit in addition to the size limit?

Linkback: https://fractalforums.org/forum-help-and-support/31/resolution-limit/2067/

Online claude

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« Reply #1 on: October 28, 2018, 06:19:32 PM »
I think there is, but I'm not sure what it is.

Also be aware that the JPEG must be decompressed to downscale it for the thumbnail, which is 67MB in this case.  Be gentle on the server!  Maybe it took too long to do that and timed out somewhere?

Offline gerrit

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« Reply #2 on: October 28, 2018, 08:06:20 PM »
Hi!

I just wanted to post a JPG with 5600*4200 and 4.829.816 bytes, but it didn't work. Uploading worked, but after clicking the Post button, a white page appeared, and nothing else happened, and the posting didn't show up in my image thread. Is there a resolution limit in addition to the size limit?
No pixel limit; it used to be a problem but was fixed this year, I've posted up to 8000*8000 but not recently, maybe some recent change reintroduced the problem.

Offline 3DickUlus

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« Reply #3 on: October 28, 2018, 10:30:01 PM »
looking into it...

absolute mem limit for GD process to resize an image is 90M, this is internal for the resize function itself, other limits are set elsewhere.

for the gallery the limits are..

Max allowed image height:    3840
Max allowed image width:    3840
Max image filesize:    (bytes)    5000000

for attachements...

Max attachment size per post                   5000kB (total)
Max size per attachment                            5000kB
Max number of attachments per post      5

exceeding these limits generates a blank, it should definitely handle this in a nicer way, reporting the cause and cleaning up the leftovers, but it doesn't... yet.
« Last Edit: October 28, 2018, 11:54:17 PM by 3DickUlus »
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Offline 3DickUlus

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« Reply #4 on: October 28, 2018, 11:58:30 PM »
I do see the error in the logs as...

Your attachment couldn't be saved. This might happen because it took too long to upload or the file is bigger than the server will allow.

..but it should be nice and actually show you that message instead of a blank.

Offline ThunderboltPagoda

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« Reply #5 on: October 30, 2018, 12:42:52 AM »
Thank you for the answers.

Claude:
Quote
Also be aware that the JPEG must be decompressed to downscale it for the thumbnail, which is 67MB in this case.

That might be the reason. As Bitmap it has around 70 MB, perhaps too much.

3DickUlus:
Quote
Your attachment couldn't be saved. This might happen because it took too long to upload or the file is bigger than the server will allow.

But it was an attachment in my image thread, and it was less than 5000000 bytes. When a file is too large, there is an error message before the upload starts, but in this case it was not beyond the limit. And the upload didn't take longer than usual.

Now I tried it again, and it still didn't work (and again the upload didn't take very long). Then I tried a resized version of the file (I think it was 5400*3900) with the same result. Then I tried it with 5000*3750, and now it worked. It's here:
https://fractalforums.org/image-threads/25/lyapunov-fractals/1779/msg10386#msg10386

Offline 3DickUlus

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« Reply #6 on: October 31, 2018, 02:17:12 AM »
not sure of the exact internal format used by GD process but assuming 4 bytes per pixel

5000*3750*4 = 75,000,000
5400*3900*4 = 84,240,000

both within the limits and should be fine but, again, I'm not sure of the requirements for the GD process itself or how much of the 90M might be used for things other than user image data, like IO buffers, stack, executable program space etc. it probably needs some for the scaled images too, thumb, medium and large + the original. I would suggest that a reasonable resolution would be 1920x1080 for attachments and 3840 x 2160 for gallery images

We set the limits in the forum admin section as you see them posted in the gallery and message system and we are as disappointed as you are that the numbers are not the "real" numbers in practice. If we change them you will still have the same sort of failures when approaching those limits and no matter how big we make them people will always try to post to the limit. The php code for the forum and gallery is available from the SMF web site and if anyone presents a solution I would be happy to apply it to the site.

Offline ThunderboltPagoda

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« Reply #7 on: November 01, 2018, 01:08:12 AM »
and we are as disappointed as you are that the numbers are not the "real" numbers in practice.

Oh, I'm not disappointed. I just wanted to know the reason for the failure, but I can perfectly live with it. No need to change anything. Thank you once again!


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