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OpenGL oputput does not work well in OpenCV on Raspberry 4

Posted: Sun Oct 06, 2019 6:12 pm
by Lich
My program processes and displays video using OpenCV. OpenCV 4.1.1 compiled with OpenGL and Qt. OS - Raspbian Buster, all updates are installed.

In the test version I start displaying H.264 HD video (1280x720) from the file without processing.

Code: Select all

vs = cv2.VideoCapture(src1)

while True:
    ret, frame =
    if ret:

1. On Raspberry 4 with the Fake KMS driver enabled, the CPU load is 35-50% (the value is constantly changing within these limits).

2. On Raspberry 3 with the Fake KMS or Full KMS driver enabled, the CPU load is 32-38%.

Both use the same image on the SD card.

Why does Raspberry 3 perform better than Raspberry 4? Is there a problem with drivers for Videocore VI?