Performance improvements

[Agade09]

To grab() a 1440x2560 screen, profiling total time spent in ctypes.string_at() went from ~20% to ~0%. A further optimization is made if grabbing a subset of the screen. Then if we want a 480x640 region of a 1440x2560 screen, only 480x2560x4 contiguous pixels need to be copied. Overall FPS improvements on my machine, grabbing 1440x2560 in BGRA ~271FPS -> ~685FPS

[ninjatall12]

Crazy optimisations, where did you get the experience to know how to improve this code?

[ra1nty]

Thanks for the commit! Interesting optimization. Let me take a look and do some benchmarks & merge

[Agade09]

@ninjatall12 Is this with dxcam in pure python or with AI-M-BOT's pyd ? Because I also have issues with the py310 binary he made.

PS: Thanks, I did a lot of competitions on Codingame and just got experience over the years at work and in personal projects. I was profiling a project of mine with pprofile and noticed that dxcam was spending a lot of time in ctypes.string_at() which just copies memory according to its description; I found this very suspicious and investigated.

[AI-M-BOT]

@Agade09 with AI-M-BOT's pyd, i am using his python 3.11 binary. thanks for the quick reply. will let him know about this

would you share the part of your script taking screenshots? was that area using windll.user32.SetWindowDisplayAffinity?

[AI-M-BOT]

reproduced, my bad

Also i will recommend using grab function instead of using start(), start function create a new thread which doesn't benefit in performance (in Python) Taking screenshots using dxgi repeatly without sleeping will dramatically lower down fps of game. Also the sleep function author used in this project is not precise enough (which sleeps around 15ms at least), i will recommend the following function:

from ctypes import windll

def nanosleep(num: float) -> None:
    windll.winmm.timeBeginPeriod(1)
    windll.kernel32.Sleep(int(num))
    windll.winmm.timeEndPeriod(1)

[crackwitz]

nanosleep

that's not a nanosleep. that gives you whole milliseconds at best. and it affects the kernel.

https://learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod

[AI-M-BOT]

nanosleep

that's not a nanosleep. that gives you whole milliseconds at best. and it affects the kernel.

https://learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod

i know, just need to sleep as precise as possible, my function name means nothing, why care about it

[AI-M-BOT]

@AI-M-BOT Thanks for the tip about sleepnig but i still face this issue after using camera.grab()

please use grab(region=region)

[Agade09]

@AI-M-BOT Could you detail how you compile these .pyd? With Nuitka, I can't get binaries as fast as yours. My binaries also don't reproduce the bug ninjatall12 and I have been seeing. I have been using python -m nuitka --lto=yes --module dxcam --include-package=dxcam.

[AI-M-BOT]

should be fine now, just replace with new file https://github.com/AI-M-BOT/DXcam/releases/tag/1.1

[AI-M-BOT]

create a file named dxshot.py or whatever you prefer, copy the content of dxcam/init.py into dxshot.py, run cmd python -m nuitka --mingw64 --module --show-progress --no-pyi-file --remove-output --follow-import-to=dxcam dxshot.py

[AI-M-BOT]

should be fine now, just replace with new file https://github.com/AI-M-BOT/DXcam/releases/tag/1.1

still the same I get this error either using cam.grab(region=region) or cam.get_latest_frame()

are you using Python 3.9? Is your testing script open source on github?

Exception ignored in: <function _compointer_base.__del__ at 0x000002A710E128B0>
Traceback (most recent call last):
  File "E:\embed_python\python39\Lib\site-packages\comtypes\__init__.py", line 956, in __del__
    self.Release()
  File "E:\embed_python\python39\Lib\site-packages\comtypes\__init__.py", line 1211, in Release
    return self.__com_Release()
OSError: exception: access violation writing 0xFFFFFFFFFFFFFFFF

I only got this and script still works. I just tested all versions with pure grab() and get_last_frame(), no issue on my laptop

[ninjatall12]

Moved on to using c++ instead of python since it better fits my usage case. massive performance bump and a lot less resource intensive was quite a pain to get opencv to work with dxgi but got there in the end.

[ParticleG]

should be fine now, just replace with new file https://github.com/AI-M-BOT/DXcam/releases/tag/1.1

still the same I get this error either using cam.grab(region=region) or cam.get_latest_frame()

are you using Python 3.9? Is your testing script open source on github?

Exception ignored in: <function _compointer_base.__del__ at 0x000002A710E128B0>
Traceback (most recent call last):
  File "E:\embed_python\python39\Lib\site-packages\comtypes\__init__.py", line 956, in __del__
    self.Release()
  File "E:\embed_python\python39\Lib\site-packages\comtypes\__init__.py", line 1211, in Release
    return self.__com_Release()
OSError: exception: access violation writing 0xFFFFFFFFFFFFFFFF

I only got this and script still works. I just tested all versions with pure grab() and get_last_frame(), no issue on my laptop

Hi, could you upload your version to pypi or provide a way that requirements.txt can use? Pycharm doesn't like .pyd files and keeps complaining about module not found errors.

[lucasmonstrox]

Moved on to using c++ instead of python since it better fits my usage case. massive performance bump and a lot less resource intensive was quite a pain to get opencv to work with dxgi but got there in the end.

Is possible to python code call your c++ code? Or use cython style?

[lucasmonstrox]

Moved on to using c++ instead of python since it better fits my usage case. massive performance bump and a lot less resource intensive was quite a pain to get opencv to work with dxgi but got there in the end.

Also, can you show me cpu usage, memory usage and FPS?