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• Python ImageIO : Too many open files

  24 août 2017, par orbv12

  I am using imageio in python in order to open all video files in a directory and convert them to numpy arrays.

  Here is the script I am using :

    1 from __future__ import print_function
  
    2 from avi_to_numpy import *
  
    3 from os import listdir
  
    4 import numpy as np
  
    5 import imageio 
  
    6       
  
    7 class_path = '../Diving/'
  
    8 max_frames = 16
  
    9 stride = 8
  
   10 videos = [vid for vid in listdir(class_path)]
  
   11 train = []
  
   12 
  
   13 for vid in videos:
  
   14     print(str.format('Loading {}...', vid), end="")
  
   15     filename = class_path + vid
  
   16     reader = imageio.get_reader(filename, 'ffmpeg')
  
   17     frames = []
  
   18     
  
   19     for i, im in enumerate(reader):
  
   20         if len(frames) == max_frames:
  
   21             break
  
   22         
  
   23         if i % stride == 0:
  
   24             frames.append(im)
  
   25     
  
   26     reader.close()
  
   27     train.append(np.array(frames))
  
   28     print('done')        
  
   29 
  
   30 
  
   31 print(len(train))

  Eventually this script crashes with the following error output :

  Traceback (most recent call last):
  
    File "load_class_test.py", line 16, in <module>
  
      reader = imageio.get_reader(filename, 'ffmpeg')
  
    File "/usr/local/lib/python2.7/site-packages/imageio/core/functions.py", line 111, in get_reader
  
      return format.get_reader(request)
  
    File "/usr/local/lib/python2.7/site-packages/imageio/core/format.py", line 158, in get_reader
  
      return self.Reader(self, request)
  
    File "/usr/local/lib/python2.7/site-packages/imageio/core/format.py", line 207, in __init__
  
      self._open(**self.request.kwargs.copy())
  
    File "/usr/local/lib/python2.7/site-packages/imageio/plugins/ffmpeg.py", line 260, in _open
  
      self._initialize()
  
    File "/usr/local/lib/python2.7/site-packages/imageio/plugins/ffmpeg.py", line 326, in _initialize
  
      stdout=sp.PIPE, stderr=sp.PIPE)
  
    File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
  
      errread, errwrite)
  
    File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1223, in _execute_child
  
      errpipe_read, errpipe_write = self.pipe_cloexec()
  
    File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1175, in pipe_cloexec
  
      r, w = os.pipe()
  
  OSError: [Errno 24] Too many open files
  
  </module>

  I am closing the Reader object from imageio. It seems as if the files opened by ffmpeg are not being closed properly.

  Is there an obvious step I am missing here ? Am I closing the files properly ?

  EDIT : Found temporary solution. Opened a new issue on github.

  I was able to resolve the issue by uncommenting the following lines of code from ’imageio/plugins/ffmpeg.py’ :

  381         def _close_streams(self):
  
  382             for std in (self._proc.stdin,
  
  383                         self._proc.stdout,
  
  384                         self._proc.stderr):
  
  385                 try:
  
  386                     std.close()
  
  387                 except Exception:  # pragma: no cover
  
  388                     pass

  I then added a call to the above function in _close(self) :

  271         def _close(self):
  
  272             self._terminate(0.05)  # Short timeout
  
  273             self._close_streams()
  
  274             self._proc = None

  I am not sure what the side effects of doing this are, but it provides a solution for me.

  Here is the link to the issue : https://github.com/imageio/imageio/issues/145

• OpenCV-C++ VideoCapture fails to open video files

  9 août 2017, par Akihiko

  Recently I upgraded my OS from Ubuntu Precise Saucy (13.10) to Trusty (14.04). After this upgrade, cv::VideoCapture became not working properly. The program aborts when reading a video file. For example,

  int main(int argc, char**argv)
  
  {
  
    cv::VideoCapture vin("sample/vout2l.avi");
  
  ...

  Executing this program, it aborts with a message :

  *** Error in `./cv2-videoread.out': malloc(): memory corruption: 0x0000000000e3eff0 ***
  
  Abort (core dumped)

  The backtrace looks like :

  [New LWP 15586]
  
  [New LWP 15587]
  
  [Thread debugging using libthread_db enabled]
  
  Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
  
  Core was generated by `./cv2-videoread.out'.
  
  Program terminated with signal SIGABRT, Aborted.
  
  #0  0x00007ff953e61c37 in raise () from /lib/x86_64-linux-gnu/libc.so.6
  
  (gdb) bt
  
  #0  0x00007ff953e61c37 in raise () from /lib/x86_64-linux-gnu/libc.so.6
  
  #1  0x00007ff953e65028 in abort () from /lib/x86_64-linux-gnu/libc.so.6
  
  #2  0x00007ff953e9e2a4 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
  
  #3  0x00007ff953eabe26 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
  
  #4  0x00007ff953eac1ab in ?? () from /lib/x86_64-linux-gnu/libc.so.6
  
  #5  0x00007ff953eadba4 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
  
  #6  0x00007ff953eaf7d2 in posix_memalign () from /lib/x86_64-linux-gnu/libc.so.6
  
  #7  0x00007ff94fa640fe in av_malloc () from /usr/lib/x86_64-linux-gnu/libavutil.so.52
  
  #8  0x00007ff94fa641b1 in av_strdup () from /usr/lib/x86_64-linux-gnu/libavutil.so.52
  
  #9  0x00007ff94fa5e5db in av_dict_set ()
  
    from /usr/lib/x86_64-linux-gnu/libavutil.so.52
  
  #10 0x00007ff954738574 in CvCapture_FFMPEG::open(char const*) ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  #11 0x00007ff954738719 in cvCreateFileCapture_FFMPEG ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  #12 0x00007ff95473aac9 in cvCreateFileCapture_FFMPEG_proxy(char const*) ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  ---Type <return> to continue, or q <return> to quit---
  
  #13 0x00007ff954722d89 in cvCreateFileCapture ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  #14 0x00007ff954723045 in cv::VideoCapture::open(std::string const&amp;) ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  #15 0x00007ff95472315c in cv::VideoCapture::VideoCapture(std::string const&amp;) ()
  
    from /usr/lib/libopencv_highgui.so.2.4
  
  #16 0x0000000000401281 in main (argc=1, argv=0x7fff1f938388) at cv2-videoread.cpp:30
  
  (gdb)
  
  </return></return>

  NOTE : cv::VideoCapture vin(... is 30th line.

  Before upgrading the OS, this code was working with the same input file.

  From the backtrace, it seems that the trouble happens at CvCapture_FFMPEG and libavutil. I upgraded the packages ffmpeg libavutil-dev libavutil51 libavutil52 but they were already up-to-date.
  Also, OpenCV packages are up-to-date (I checked libopencv-core-dev libopencv-core2.4 libopencv-dev libopencv-highgui-dev libopencv-highgui2.4).

  I also tested OpenCV built from source, but got the same results.

  Do you have ideas to figure this out ?

• rmdec : add missing brackets to compound statement

  25 juillet 2017, par Sean McGovern

  rmdec : add missing brackets to compound statement
  Accidentally left out of 95ce02b35d3d1bb16111031df1d82a6e4d894d36.
  

  • [DBH] libavformat/rmdec.c