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• How to estimate bandwidth / speed requirements for real-time streaming video ?

  19 juin 2016, par Vivek Seth

  For a project I’m working on, I’m trying to stream video to an iPhone through its headphone jack. My estimated bitrate is about 200kbps (If i’m wrong about this, please ignore that).

  I’d like to squeeze as much performance out of this bitrate as possible and sound is not important for me, only video. My understanding is that to stream a a real-time video I will need to encode it with some codec on-the-fly and send compressed frames to the iPhone for it to decode and render. Based on my research, it seems that H.265 is one of the most space efficient codecs available so i’m considering using that.

  Assuming my basic understanding of live streaming is correct, how would I estimate the FPS I could achieve for a given resolution using the H.265 codec ?

  The best solution I can think of it to take a video file, encode it with H.265 and trim it to 1 minute of length to see how large the file is. The issue I see with this approach is that I think my calculations would include some overhead from the video container format (AVI, MKV, etc) and from the audio channels that I don’t care about.

• Preload reference area in sub-pixel motion search (real-time mode)

  22 juillet 2011, par Yunqing Wang

  Preload reference area in sub-pixel motion search (real-time mode)

• Get image output from python program and use ffmpeg push the real time video stream to web

  26 mai 2018, par Nick Tseng

  I have a question. How to push a real time video streaming after processing ?

  First, below program is to preprocess image from usbcamera

  Second, push the image into real time video streaming by another process (ffmpeg -r 29 -i test.avi http://ffserver IP:8090/camera.ffm)

  cap = cv2.VideoCapture(1) ##activate usbcamera
  
  
  
  frame_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
  
  frame_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
  
  
  
  ysize, xsize = frame_height , frame_width
  
  
  
  filepath = 'test.avi'
  
  fourcc = cv2.VideoWriter_fourcc(*'MJPG')
  
  out = cv2.VideoWriter(filepath , fourcc , 29.0 , (frame_width , frame_height),True)
  
  
  
  while(cap.isOpened()):
  
  
  
      #read camera image
  
      ret , frame = cap.read()
  
  
  
      #color selection
  
      tmp = color_select_test(frame)
  
  
  
      # Mix with original image
  
      tmp = weighted_img(tmp, frame, 0.5, 1.0, 0.0)
  
  
  
      # write in video file
  
      out.write(tmp)
  
  
  
      #cv2.imwrite('test.avi',tmp)
  
  
  
      cv2.imshow('FrameWrite' , tmp)
  
  
  
      if(cv2.waitKey(1) == 27):
  
          ##cv2.imwrite('test_blue.jpg',frame)
  
          break
  
  cap.release()
  
  cv2.destroyAllWindows()