title: Get different valid frame number from the same video on different cpu using opencv-python?
body: <p>I am using opencv-python==4.2.0.32 to extract frames from videos following the code.</p>
  <pre><code>def read_1(self, video_path, delta=0.5):
          video  = cv2.VideoCapture(video_path)
          fps    = video.get(cv2.CAP_PROP_FPS)
          frames = math.ceil(video.get(cv2.CAP_PROP_FRAME_COUNT))
          step = int(fps * delta)
          print(f'fps: {fps} step: {step} frames: {frames}')
      
          for i in range(frames):
              flag, img = video.read()
              if flag:
                  yield img
  </code></pre>
  <p>However, for some videos, the valid frame number is totally different on different CPU machines. Is it caused by hardware or the codecs?</p>
  <p>Does anybody meet this problem?</p>