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• Anomalie #2987 (Fermé) : Liste a puce dans tableau : erreur 500 dans logfile + PHP has encountered...

  3 mai 2013, par cedric -

  voir #2934 : c’est un problème lié au module PCRE de PHP 5.2...

• 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.