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• VideoCapture is not working in OpenCV 2.4.2

  31 mai 2016, par Froyo

  I recently installed OpenCV 2.4.2 in Ubuntu 12.04.

  cap = VideoCapture(0)

  is working. but I can’t grab frames from some video source.

  cap = VideoCapture("input.avi")
  
  img = cap.read() 

  gives me a numpy with all zero elements.

  I have also installed ffmpeg 0.11, Latest snapshot of x264, v4l-0.8.8 (All are latest stable versions)

  cmake -D WITH_QT=ON -D WITH_FFMPEG=ON -D WITH_OPENGL=ON -D WITH_TBB=ON -D BUILD_EXAMPLES=OFF WITH_V4L=ON .. 
  
  make
  
  sudo make install

  When I do cmake, I get this

  — Detected version of GNU GCC : 46 (406)
  — Found OpenEXR : /usr/lib/libIlmImf.so
  — Looking for linux/videodev.h
  — Looking for linux/videodev.h - not found
  — Looking for linux/videodev2.h
  — Looking for linux/videodev2.h - found
  — Looking for libavformat/avformat.h
  — Looking for libavformat/avformat.h - found
  — Looking for ffmpeg/avformat.h
  — Looking for ffmpeg/avformat.h - not found
  — checking for module ’tbb’
  — package ’tbb’ not found

  And

  --   Video I/O:  
  
  --     DC1394 1.x:                  NO  
  
  --     DC1394 2.x:                  YES (ver 2.2.0)  
  
  --     FFMPEG:                      YES  
  
  --       codec:                     YES (ver 54.23.100)  
  
  --       format:                    YES (ver 54.6.100)  
  
  --       util:                      YES (ver 51.54.100)  
  
  --       swscale:                   YES (ver 2.1.100)  
  
  --       gentoo-style:              YES  
  
  --     GStreamer:                   
  
  --       base:                      YES (ver 0.10.36)  
  
  --       app:                       YES (ver 0.10.36)  
  
  --       video:                     YES (ver 0.10.36)  
  
  --     OpenNI:                      NO  
  
  --     OpenNI PrimeSensor Modules:  NO  
  
  --     PvAPI:                       NO  
  
  --     UniCap:                      NO  
  
  --     UniCap ucil:                 NO  
  
  --     V4L/V4L2:                    Using libv4l (ver 0.8.8)  
  
  --     XIMEA:                       NO  
  
  --     Xine:                        NO

  I looked for videodev.h, etc

  • /usr/include/linux/videodev2.h exists
  • /usr/include/libavformat/avformat.h exists
  • /usr/local/include/libavformat/avformat.h exists

  But I couldn’t find ffmpeg/avformat.h

  What’s the problem here ?

• Cannot run ffmpeg in subproces.call

  27 juin 2012, par Richard Knop

  So, I have a simple class where I am trying to save a string response from a terminal ffmpeg command into an object property :

  import os
  
  import subprocess
  
  
  
  class Movie(object):
  
  
  
      absolute_path = None
  
      movie_info = None
  
  
  
      def __init__(self, path):
  
          self.absolute_path = "%s/%s" % (os.getcwd(), path)
  
          if(os.path.exists(self.absolute_path) is False):
  
              raise IOError("File does not exist")
  
  
  
      def get_movie_info(self):
  
          ffmpeg_command = "ffmpeg -i %s" % self.absolute_path
  
          self.movie_info = subprocess.call(ffmpeg_command)
  
          print self.movie_info

  When I then run this command in cmd :

  import os
  
  import sys
  
  sys.path.append(os.getcwd())
  
  
  
  from Encode.Movie import Movie
  
  
  
  try:
  
      movie = Movie("tests/test_1.mpg")
  
      movie.get_movie_info()
  
  except IOError as e:
  
      print e

  I get this exception :

  richard@richard-desktop:~/projects/hello-python$ python main.py 
  
  Traceback (most recent call last):
  
    File "main.py", line 9, in <module>
  
      movie.get_movie_info()
  
    File "/home/richard/projects/hello-python/Encode/Movie.py", line 16, in get_movie_info
  
      self.movie_info = subprocess.call(ffmpeg_command)
  
    File "/usr/lib/python2.7/subprocess.py", line 493, in call
  
      return Popen(*popenargs, **kwargs).wait()
  
    File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
  
      errread, errwrite)
  
    File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
  
      raise child_exception
  
  OSError: [Errno 2] No such file or directory
  
  </module>

  The path is correct because when I do print self.absolute_path before subprocess.call(), I get :

  /home/richard/projects/hello-python/tests/test_1.mpg

  And this file exists.

• Install FFMPEG on WAMP

  1er décembre 2014, par nico55555

  I’ve probably spent over 12 hours trying to install FFMPEG on WAMP. I’m aware that other people have had this question answered on this site, however it does not work for my setup.

  I have tried the below :

  Download ffmpeg_new
  
  Copy php_ffmpeg.dll from the php5 folder to the C:\wamp\bin\php\php5.2.9-2\ext
  
  Copy files from common to the windows/system32 folder
  
  Add extension=php_ffmpeg.dll to php.ini file
  
  Restarted all services (Apache, PHP...)

  My current setup is PHP 5.2.1, Apache 2.0.63. I have a Windows 7 64bit computer.

  I get the following error in my PHP error log :

  [22-Jun-2012 01:39:31] PHP Warning : PHP Startup : Unable to load dynamic library ’c :/wamp/bin/php/php5.2.1/ext/php_ffmpeg.dll’ - The specified module could not be found.
  in Unknown on line 0

  Obviously I have placed the module in the ext folder.

  Phpinfo.php verifies that the FFMPEG module is not being loaded. I have tried installing PHP 5.3 (with a later FFMPEG version), 5.2.6 and 5.2.9-2, but the module still fails to load. Is there anything else I should try ? Does having a 64bit Windows 7 computer make any difference ?