Adding a coroutine with a webcam feed to a running asyncio loop stops tasks from running

huangapple
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英文:

Adding a coroutine with a webcam feed to a running asyncio loop stops tasks from running

问题

如果我运行1+n个异步问候循环，一切都运行正常。但每当我添加runCamera方法，它会停止问候循环的运行。为什么会发生这种情况？或者这更适合使用线程吗？我希望问候循环和摄像头图像同时显示。

  1. def main():
  2.     loop = asyncio.get_event_loop()
  3.     asyncio.ensure_future(greet_every_two_seconds())
  4.     asyncio.ensure_future(runCamera())
  5.     loop.run_forever()
  7. async def greet_every_two_seconds():
  8.     while True:
  9.         print('Hello World')
  10.         await asyncio.sleep(1)
  12. async def runCamera():
  13.     vid = cv.VideoCapture(0)
  15.     while (True):
  16.         ret, frame = vid.read()
  17.         cv.imshow('frame', frame)
  18.         if cv.waitKey(1) & 0xFF == ord('q'):
  19.             break
  21.     vid.release()
  22.     cv.destroyAllWindows()
英文:

If I run 1+n async greeting loops everything works fine. Whenever I add the runCamera method, it stops the greeting loops from running. Why is this happening? Or is this rather a case for threading? I want the greeting loops to run and the webcam image showing at the same time.

  1.     def main():
  2.         loop = asyncio.get_event_loop()
  3.         asyncio.ensure_future(greet_every_two_seconds())
  4.         asyncio.ensure_future(runCamera())
  5.         loop.run_forever()
  7.     async def greet_every_two_seconds():
  8.         while True:
  9.           print('Hello World')
  10.           await asyncio.sleep(1)
  12.     async def runCamera():
  13.         vid = cv.VideoCapture(0)
  15.         while (True):
  16.            ret, frame = vid.read()
  17.           cv.imshow('frame', frame)
  18.            if cv.waitKey(1) & 0xFF == ord('q'):
  19.                break
  21.         vid.release()
  22.         cv.destroyAllWindows()

答案1

得分: 0

这是代码部分，无需翻译。

英文:

It is a matter of threading and my guess is that that is due to: Threading provides thread-based concurrency, suitable for blocking I/O tasks - Asyncio doesnt.

Solution based on the two methods shown above (greet_every_two_seconds and runCamera) looks like this:

  1. def main():
  2.     server = threading.Thread(target=start_cam, daemon=True)
  3.     server.start()
  4.     client = threading.Thread(target=client_call)
  5.     client.start()
  6.     client.join()
  9. def start_greeting():
  10.     loop = asyncio.new_event_loop()
  11.     asyncio.set_event_loop(loop)
  12.     asyncio.ensure_future(greet_every_two_seconds())
  13.     loop.run_forever()
  15. def start_cam():
  16.     loop = asyncio.new_event_loop()
  17.     asyncio.set_event_loop(loop)
  18.     asyncio.ensure_future(runCamera())
  19.     loop.run_forever()

huangapple
  • 本文由 发表于 2023年2月16日 17:34:23
  • 转载请务必保留本文链接：https://go.coder-hub.com/75470290.html
  • opencv
  • python
  • python-asyncio
  • video-capture
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