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OpenCV minimal example showing multithreaded video processing.
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# Original code here: | |
# https://github.com/opencv/opencv/blob/master/samples/python/video_threaded.py | |
#!/usr/bin/env python3 | |
''' | |
Multithreaded video processing minimal sample. | |
Usage: | |
python3 video_threaded.py | |
Shows how python threading capabilities can be used | |
to organize parallel captured frame processing pipeline | |
for smoother playback. | |
Keyboard shortcuts: | |
ESC - exit | |
''' | |
from collections import deque | |
from multiprocessing.pool import ThreadPool | |
import cv2 as cv | |
VIDEO_SOURCE = 0 | |
def process_frame(frame): | |
# some intensive computation... | |
frame = cv.medianBlur(frame, 19) | |
return frame | |
if __name__ == '__main__': | |
# Setup. | |
cap = cv.VideoCapture(VIDEO_SOURCE) | |
thread_num = cv.getNumberOfCPUs() | |
pool = ThreadPool(processes=thread_num) | |
pending_task = deque() | |
while True: | |
# Consume the queue. | |
while len(pending_task) > 0 and pending_task[0].ready(): | |
res = pending_task.popleft().get() | |
cv.imshow('threaded video', res) | |
# Populate the queue. | |
if len(pending_task) < thread_num: | |
frame_got, frame = cap.read() | |
if frame_got: | |
task = pool.apply_async(process_frame, (frame.copy(),)) | |
pending_task.append(task) | |
# Show preview. | |
if cv.waitKey(1) == 27 or not frame_got: | |
break | |
cv.destroyAllWindows() |
It is.
i have tested the scipt and add to disolay the FPS but i get 8, when i move my hand the fps goes up to 17. i measure it in the while loop
while len(pending_task) > 0 and pending_task[0].ready():
res = pending_task.popleft().get()
# fps calulation
....
may be i make a mistake, fps is low.
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Isn't this just a near straight up copy from the official documentation? https://github.com/opencv/opencv/blob/master/samples/python/video_threaded.py