Issues with VideoCapture.set

Python
1

Hi,

I want to use openCV to control in python a webcam from an embedded system. I did this code to manage the resolution of the capture:

import cv2

capture = cv2.VideoCapture(0, cv2.CAP_V4L2)

capture.set(3, 1280)
capture.set(4, 720)

However, the resolution of this capture is stuck at the basic resolution for cv2: 640*480.

The webcam is the nuroum V11 (https://resource.auditoryworks.co/newNuroum/support/resource/nuroum%20V11%20datasheet.pdf)

The embedded system is a RFSoC 4x2
(https://www.realdigital.org/downloads/f04f64ad8cc422d64a6ce85580d40834.pdf)

I use a jupyter notebook and PYNQ to execute the previous python code in the Processing System of the board.

Has someone meet a similar issue with that webcam?

Thank you in advance for your assistance

2

try access using ffmpeg or gstreamer or guvcview or other way that isn’t opencv, but also uses V4L2

some video modes might require CAP_PROP_FOURCC set to VideoWriter_fourcc(*"MJPG"). order of set() calls matters, try setting this property first and last (not first and last, first first, then last)

general programming advice: named constants please. cv.CAP_PROP_FRAME_WIDTH etc

1 Like
3

Hi,

Thank you for your answer. I changed the previous code to:

capture = cv2.VideoCapture(0, cv2.CAP_V4L2)

capture.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*“MJPG”))

capture.set(cv2.CAP_PROP_FRAME_WIDTH, 1920)
capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080)

With that, I am able to change the resolution of the capture. Thank you once again