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• threading with open cv and FFMPEG

  3 février 2023, par share2020 uis

  I'm working on a project which get several CCTV streams and preform some processing with OpenCV. Then I want to get those streams back with rtmp/rtsp protocols.

  


  I can use openCV with threading in python and preform my processing and return in scale of 4 frames from each stream sequentially.
Is there any way to use this python library and FFMPEG to send each stream to corresponding rtmp/rtsp with FFMPG ?

  


  `class LoadStreams:  # multiple IP or RTSP cameras
  def __init__(self, sources='streams.txt', img_size =(1290,720)):
      self.mode = 'images'
      self.img_size = img_size


      if os.path.isfile(sources):
          with open(sources, 'r') as f:
              sources = [x.strip() for x in f.read().splitlines() if len(x.strip())]
      else:
          sources = [sources]

      n = len(sources)
      self.imgs = [None] * n
      self.sources = sources
      for i, s in enumerate(sources):
          cap = cv2.VideoCapture(eval(s) if s.isnumeric() else s)
          assert cap.isOpened(), 'Failed to open %s' % s
          w = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
          h = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
          self.fps = cap.get(cv2.CAP_PROP_FPS) % 100
          _, self.imgs[i] = cap.read()  # guarantee first frame
          thread = Thread(target=self.update, args=([i, cap]), daemon=True)
          print(' success (%gx%g at %.2f FPS).' % (w, h, self.fps))
          thread.start()


  def update(self, index, cap):
      n = 0
      while cap.isOpened():
          n += 1
          # _, self.imgs[index] = cap.read()
          cap.grab()
          if n == 4:  # read every 4th frame
              _, self.imgs[index] = cap.retrieve()
              n = 0
          time.sleep(0.01)  # wait time

  def __iter__(self):
      self.count = -1
      return self

  def __next__(self):
      self.count += 1
      img0 = self.imgs.copy()
      if cv2.waitKey(1) == ord('q'):  # q to quit
          cv2.destroyAllWindows()
          raise StopIteration`


  


  enter image description here

  


  Being able to use ffmpeg for n frames from A_in streaming to A_out url and get n from B_in url stream to B_out url.

  


• Streaming video from nodejs to an open player

  27 août 2013, par Matthew Young

  Odd ball question for somebody just getting started with html5 players and streaming video....

  When using YouTube long videos can be scrolled towards then end then played from there. Assuming YouTube first pulls down metadata like total video start/stop points and a bunch of thumbnails for scrolling.

  Is this possible with an open html5 video player (like projekkter) ? Reason asking is that I have video data inside a mongo database that I would like to stream similar to the YouTube player.

  Inside mongo I have a bunch of smaller h264 files each in a document : actual raw h264 usually 1000kb (max 2 seconds), creation timestamp (long), and potentially a converted format (like mp4) for known clients. Idea is to query off a time range and order by creation time then piping the results into readable stream. There is a nice ffmpeg module to take streams and reformat if needed. Thought about piping the stream to the client with binaryjs and appending it into the player.

  But the source directives in the documentation are usually URLs plus I need to lock down the start/stop point for the total video being played plus thumbnails.

• Revision 09830aa0ea : Small tweaks on the constant quality mode Improves results a little. derf is no

  10 septembre 2013, par Deb Mukherjee

  Changed Paths :
   Modify /vp9/encoder/vp9_onyx_if.c

  
  
  Small tweaks on the constant quality mode

  Improves results a little.
  derf is now +1.078% over bitrate control.

  Change-Id : I4812136f3e67be21d14ec089419976a32a841785