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• Revision 32979 : meilleure structure pour les liens du .meta-publi on retient pour le ...

  15 novembre 2009, par cedric@… — Log

  meilleure structure pour les liens du .meta-publi on retient pour le titre dans le lien "Lire la suite de .."

• How to directly embed an flv in actionscript so ffmpeg can convert from the compiled swf ?

  3 décembre 2012, par user1872755

  I have an flv that needs to be embedded into a swf. I am currently using the Embed tag and playing the flv with NetStream. The problem is that it does not seem to be directly embedding the flv file, as ffmpeg does not detect it. I am currently using mxmlc to compile. If published from Flash Professional the conversion works. I can't use Flash Professional because I need to use the command line. Is there a way to embed an FLV in actionscript and have ffmpeg convert it ?

• Python : What's the fastest way to load a video file into memory ?

  8 juillet 2017, par michaelh

  First some background

  I am trying to write my own set of tools for video analysis, mainly for detecting render errors like flashing frames and possibly some other stuff in the future.

  The (obvious) goal is to write a script, that is faster and more accurate than me watching the file in real time.

  Using OpenCV, I have something that looks like this :

  import cv2
  
  
  
  
  
  vid = cv2.VideoCapture("Video/OpenCV_Testfile.mov", cv2.CAP_FFMPEG)
  
  width = 1024
  
  height = 576
  
  length = vid.get(cv2.CAP_PROP_FRAME_COUNT)
  
  
  
  for f in range(length):
  
      blue_values = []
  
      vid.set(cv2.CAP_PROP_POS_FRAMES, f)
  
      is_read, frame = vid.read()
  
      if is_read:
  
          for row in range(height):
  
              for col in range(width):
  
                  blue_values.append(frame[row][col][0])
  
      print(blue_values)
  
  vid.release()

  This just prints out a list of all blue values of every frame.
   Just for simplicity (My actual script compares a few values across each frame and only saves the frame number when all are equal)

  Although this works, it is not a very fast operation. (Nested loops, but most important, the read() method has to be called for every frame, which is rather slow.
  I tried to use multiprocessing but basically ended up having the same crashes as described here :

  how to get frames from video in parallel using cv2 & multiprocessing in python

  I have a 20s long 1024x576@25fps Testfile which performs as follows :

  • mov, ProRes : 15s
  • mp4, h.264 : 30s (too slow)

  My machine is capable of playing back h.264 in 1920x1080@50fps with mplayer (which uses ffmpeg to decode). So, I should be able to get more out of this. Which leads me to

  my Question

  How can I decode a video and simply dump all pixel values into a list for further (possibly multithreaded) operations ? Speed is really all that matters. Note : I’m not fixated on OpenCV. Whatever works best.

  Thanks !