cv2.imshow freezes after av is imported

[samiamlabs]

Overview

My setup is a docker container with Ubuntu 22.04 and python 3.10 and av installed through pip as a dependency of aiortc.

The python scripts freeze on the cv2.imshow line after av is imported. There is no opencv window either.
If I don't import av it works.

Expected behavior

The pip installed version of av should not cause any issues for opencv.

Actual behavior

cv2.imshow does not work after av is imported

Traceback:
There is no error print or traceback, and I was not able to find any info additional info through the VSCode debugger.

Investigation

I tried building/installing v10.0.0 of PyAV from the source, which fixed the issue.

Reproduction

import cv2
import numpy as np

import av

def main(args=None):
    img = np.zeros((200, 200, 3), dtype=np.uint8)
    cv2.imshow('ImageWindow', img)
    cv2.waitKey()

if __name__ == '__main__':
    main()

Versions

• OS: Ubuntu 22.04
• PyAV versions: 9 and greater

[HanzCEO]

So the solution was to upgrade to pyav 10?

[jlaine]

Looks like a re-occurrence of #978 . Is this still current with PyAV 10?

[marcusvaltonen]

Looks like a re-occurrence of #978 . Is this still current with PyAV 10?

With Python 3.9.14 on Ubuntu 20.04 and

av==10.0.0
opencv-python==4.7.0.72

I still get this issue. EDIT: Without building from source.

[Linusnie]

As a temporary fix I found that calling cv2.imshow before import av prevents the freeze:

import numpy as np
import cv2
cv2.imshow('ffmpeg fix', np.array([1], dtype=np.uint8))
cv2.destroyAllWindows()
import av

red = np.ones((256, 256, 3)) * np.array([0, 0, 255])

cv2.imshow("red", red.astype(np.uint8))

cv2.waitKey(0)
cv2.destroyAllWindows()

[coder111111]

I can verify this issue still happens with opencv-python 4.7.0.72 and av 10.0.0
Running Debian/Sid, x64

[hmasum52]

I am facing the issue in raspberry pi 4.
python 3.11
av==12.1.0
opencv-python==4.10.0.82

What is the fix?