mirror of
https://github.com/opencv/opencv.git
synced 2024-11-25 19:50:38 +08:00
68 lines
1.9 KiB
Python
68 lines
1.9 KiB
Python
#!/usr/bin/env python
|
|
|
|
'''
|
|
VideoCapture sample showcasing some features of the Video4Linux2 backend
|
|
|
|
Sample shows how VideoCapture class can be used to control parameters
|
|
of a webcam such as focus or framerate.
|
|
Also the sample provides an example how to access raw images delivered
|
|
by the hardware to get a grayscale image in a very efficient fashion.
|
|
|
|
Keys:
|
|
ESC - exit
|
|
g - toggle optimized grayscale conversion
|
|
|
|
'''
|
|
|
|
# Python 2/3 compatibility
|
|
from __future__ import print_function
|
|
|
|
import cv2
|
|
|
|
def decode_fourcc(v):
|
|
v = int(v)
|
|
return "".join([chr((v >> 8 * i) & 0xFF) for i in range(4)])
|
|
|
|
font = cv2.FONT_HERSHEY_SIMPLEX
|
|
color = (0, 255, 0)
|
|
|
|
cap = cv2.VideoCapture(0)
|
|
cap.set(cv2.CAP_PROP_AUTOFOCUS, False) # Known bug: https://github.com/opencv/opencv/pull/5474
|
|
|
|
cv2.namedWindow("Video")
|
|
|
|
convert_rgb = True
|
|
fps = int(cap.get(cv2.CAP_PROP_FPS))
|
|
focus = int(min(cap.get(cv2.CAP_PROP_FOCUS) * 100, 2**31-1)) # ceil focus to C_LONG as Python3 int can go to +inf
|
|
|
|
cv2.createTrackbar("FPS", "Video", fps, 30, lambda v: cap.set(cv2.CAP_PROP_FPS, v))
|
|
cv2.createTrackbar("Focus", "Video", focus, 100, lambda v: cap.set(cv2.CAP_PROP_FOCUS, v / 100))
|
|
|
|
while True:
|
|
status, img = cap.read()
|
|
|
|
fourcc = decode_fourcc(cap.get(cv2.CAP_PROP_FOURCC))
|
|
|
|
fps = cap.get(cv2.CAP_PROP_FPS)
|
|
|
|
if not bool(cap.get(cv2.CAP_PROP_CONVERT_RGB)):
|
|
if fourcc == "MJPG":
|
|
img = cv2.imdecode(img, cv2.IMREAD_GRAYSCALE)
|
|
elif fourcc == "YUYV":
|
|
img = cv2.cvtColor(img, cv2.COLOR_YUV2GRAY_YUYV)
|
|
else:
|
|
print("unsupported format")
|
|
break
|
|
|
|
cv2.putText(img, "Mode: {}".format(fourcc), (15, 40), font, 1.0, color)
|
|
cv2.putText(img, "FPS: {}".format(fps), (15, 80), font, 1.0, color)
|
|
cv2.imshow("Video", img)
|
|
|
|
k = cv2.waitKey(1)
|
|
|
|
if k == 27:
|
|
break
|
|
elif k == ord('g'):
|
|
convert_rgb = not convert_rgb
|
|
cap.set(cv2.CAP_PROP_CONVERT_RGB, convert_rgb)
|