无法使用opencv获得我想要的分辨率

Question

import cv2
import numpy as np
cap = cv2.VideoCapture(1)
cap.set(3,1920)
cap.set(4,1080)

while(1):
    _,frame = cap.read()
    cv2.imshow("capture", frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        cv2.imwrite("save.jpg", frame)
        break
cap.release()
cv2.destroyAllWindows()

When I set the resolution to 1920*1080, I get the save.jpg with 1920*1080. But I get save .jpg with 1280*720 when I set the resolution to 1280*1024. Is this the problem with opencv or the camera? Any suggestions？ Thanks very much！

Answer 1

1920x1080 has aspect ratio of 16:9, when you change the resolution OpenCV preserved the aspect ratio, hence 1280x720, which also has aspect ratio 16:9.

If you are desperate to get 1280x1024, I'd recommend you capture 1920x1080 and then crop the necessary part from the middle.