64 bit SC Crashes

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Re: 64 bit SC Crashes

Post by admin » Thu Mar 19, 2020 5:37 pm

Ah, interesting. I think I still have a motherboard with an i7 870 CPU in it - unfortunately not in a case with PSU at the moment, but if I can get it up and running then I can try testing on that machine.

thanks for the report,

Robin

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Re: 64 bit SC Crashes

Post by admin » Wed Mar 25, 2020 8:51 pm

Well, the good news is that I can now make this bug happen - I had to resurrect my old PC motherboard CPU that had been on the point of being thrown out. Unfortunately I did not have a spare case to fit it, but a little open heart surgery on another PC got it up and running...
IMG_20200325_204739.jpg
IMG_20200325_204739.jpg (238.01 KiB) Viewed 34 times
For some reason the OpenCV libraries I am using decide they can run AVX instructions on this CPU in 64 bit mode when it doesn't support the AVX instruction set. Odd that it is fine in 32 bit mode.

More digging required...

cheers, Robin

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Re: 64 bit SC Crashes

Post by admin » Thu Mar 26, 2020 9:06 pm

Hi,

I can now confirm that the problem occurs on CPUs that do not support the AVX instruction set with the 64 bit version of SharpCap. This is related to an OpenCV bug :

https://github.com/opencv/opencv/issues/15690

This bug is a problem in the version of openCV that SharpCap currently uses (3.4.0) and also in 3.4.8. Apparently it may be fixed in version 4.0, but I'm reluctant to upgrade to that before SharpCap 3.3. There is also some suggestion that it may be broken again in the very latest open CV :-(

I don't want to disable AVX instructions as that would likely slow down things like live stacking on more modern CPUs. I think I'm going to have to leave this as an unresolved issue until I get a chance to update to a much newer open CV in SharpCap 3.3.

Cheers, Robin

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