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letmaik / pyvirtualcam

🎥 Send frames to a virtual camera from Python
GNU General Public License v2.0
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Framebuffers are allocated each frame #18

Closed JayFoxRox closed 3 years ago

JayFoxRox commented 3 years ago

This allocation is probably rather slow:

https://github.com/letmaik/pyvirtualcam/blob/44b4184b5cae2edaec45e974babff9ebcf9ff410/pyvirtualcam/native_windows/main.cpp#L22-L25

Instead, it should be allocated once at start, then free'd during stop.

letmaik commented 3 years ago

I don't think memory allocation is slow these days, and considering the typical framerates that would be used it's probably fine. I never saw performance issues myself. I agree though, there's no reason to be wasteful.

JayFoxRox commented 3 years ago

I never saw performance issues myself

Yes, it's probably not bad here, because it's at most 8 * 1080 (= 64 bit pointers at 1080p = ) bytes on most machines. Even then it's only 3x 4kiB pages of memory.

However, in #16 I just copied the general code-style and it's allocating the entire framebuffer - even if it might still not be perceivable, it's still bad practice. That said, the RGB → UYVY conversion in #16 is much worse for performance.

I don't think memory allocation is slow these days

I have written fair bit of graphics related code where allocations were bottleneck in relatively hot-loops. So best to avoid any potential issue.