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• FFMPEG VS Shaka Packager

  6 mai 2021, par Diogo Crava

  I want to understand in more detail the difference in capabilities between FFMPEG and Shaka Packager.
I know that the purpose of FFMPEG is to transcode and modify videos while Shaka Packager is to apply Widevine DRM to the videos but doesn't Shaka also transcode MP4 to DASH ? Doesn't FFMPEG also encrypt videos ?
I'm a bit confused in this gray area.

  


• Issue opening video file with OpenCV VideoCapture

  6 décembre 2017, par user1938805

  I’ve been reviewing the multitudes of similar questions for this issue, but I’m afraid I just cannot figure out why I cannot open a file in opencv

  I have a file "small.avi", which is a reencoding of "small.mp4" that I got from the internet. I reencoded it with ffmpeg -i small.mp4 small.avi, and I did this because I couldn’t open a mp4 file either and online it recommended trying an avi format first.

  Here is my code (mostly copied from a tutorial, with a few lines to show some relevant info) :

  import cv2
  
  import os
  
  
  
  for _, __, files in os.walk("."):
  
      for file in files:
  
          print file
  
  print ""
  
  
  
  cap = cv2.VideoCapture("small.mp4")
  
  print cap.isOpened()
  
  print cap.open("small.avi")
  
  i = 0
  
  while cap.isOpened() and i < 10:
  
      i += 1
  
      ret, frame = cap.read()
  
      print "read a frame"
  
      gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
  
      cv2.imshow('frame', gray)
  
      if cv2.waitKey(1) & 0xFF == ord('q'):
  
          break
  
  cap.release()
  
  cv2.destroyAllWindows()

  This produces the following output :

  "A:\Program Files\AnacondaPY\Anaconda\python.exe" A:/Documents/Final/VideoProcessor.py
  
  small.avi
  
  small.mp4
  
  VideoProcessor.py
  
  
  
  False
  
  False
  
  
  
  Process finished with exit code 0

  My program does not appear to properly open either file. Following the advice of

  Can not Read or Play a Video in OpenCV+Python using VideoCapture

  and

  Cannot open ".mp4" video files using OpenCV 2.4.3, Python 2.7 in Windows 7 machine,

  I found my cv2 version to be 3.0.0, went to

  A :\Downloads\opencv\build\x86\vc12\bin

  and copied the file opencv_ffmpeg300.dll to

  A :\Program Files\AnacondaPY\Anaconda

  Despite this, the code still does not successfully open the video file. I even tried the x64 versions, and tried naming the file opencv_ffmpeg.dll, opencv_ffmpeg300.dll, and opencv_ffmpeg300_64.dll (for the x64 version). Is there anything else I can try to fix this ?

  Thanks for any help

• Issue opening video file with OpenCV VideoCapture

  1er mai 2017, par user1938805

  I’ve been reviewing the multitudes of similar questions for this issue, but I’m afraid I just cannot figure out why I cannot open a file in opencv

  I have a file "small.avi", which is a reencoding of "small.mp4" that I got from the internet. I reencoded it with ffmpeg -i small.mp4 small.avi, and I did this because I couldn’t open a mp4 file either and online it recommended trying an avi format first.

  Here is my code (mostly copied from a tutorial, with a few lines to show some relevant info) :

  import cv2
  
  import os
  
  
  
  for _, __, files in os.walk("."):
  
      for file in files:
  
          print file
  
  print ""
  
  
  
  cap = cv2.VideoCapture("small.mp4")
  
  print cap.isOpened()
  
  print cap.open("small.avi")
  
  i = 0
  
  while cap.isOpened() and i < 10:
  
      i += 1
  
      ret, frame = cap.read()
  
      print "read a frame"
  
      gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
  
      cv2.imshow('frame', gray)
  
      if cv2.waitKey(1) & 0xFF == ord('q'):
  
          break
  
  cap.release()
  
  cv2.destroyAllWindows()

  This produces the following output :

  "A:\Program Files\AnacondaPY\Anaconda\python.exe" A:/Documents/Final/VideoProcessor.py
  
  small.avi
  
  small.mp4
  
  VideoProcessor.py
  
  
  
  False
  
  False
  
  
  
  Process finished with exit code 0

  My program does not appear to properly open either file. Following the advice of

  Can not Read or Play a Video in OpenCV+Python using VideoCapture

  and

  Cannot open ".mp4" video files using OpenCV 2.4.3, Python 2.7 in Windows 7 machine,

  I found my cv2 version to be 3.0.0, went to

  A :\Downloads\opencv\build\x86\vc12\bin

  and copied the file opencv_ffmpeg300.dll to

  A :\Program Files\AnacondaPY\Anaconda

  Despite this, the code still does not successfully open the video file. I even tried the x64 versions, and tried naming the file opencv_ffmpeg.dll, opencv_ffmpeg300.dll, and opencv_ffmpeg300_64.dll (for the x64 version). Is there anything else I can try to fix this ?

  Thanks for any help