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• Getting video properties with Python without calling external software

  24 juillet 2019, par ullix

  [Update :] Yes, it is possible, now some 20 months later. See Update3 below ! [/update]

  Is that really impossible ? All I could find were variants of calling FFmpeg (or other software). My current solution is shown below, but what I really would like to get for portability is a Python-only solution that doesn’t require users to install additional software.

  After all, I can easily play videos using PyQt’s Phonon, yet I can’t get simply things like dimension or duration of the video ?

  My solution uses ffmpy (http://ffmpy.readthedocs.io/en/latest/ffmpy.html ) which is a wrapper for FFmpeg and FFprobe (http://trac.ffmpeg.org/wiki/FFprobeTips). Smoother than other offerings, yet it still requires an additional FFmpeg installation.

      import ffmpy, subprocess, json
  
      ffprobe = ffmpy.FFprobe(global_options="-loglevel quiet -sexagesimal -of json -show_entries stream=width,height,duration -show_entries format=duration -select_streams v:0", inputs={"myvideo.mp4": None})
  
      print("ffprobe.cmd:", ffprobe.cmd)  # printout the resulting ffprobe shell command
  
      stdout, stderr = ffprobe.run(stderr=subprocess.PIPE, stdout=subprocess.PIPE)
  
      # std* is byte sequence, but json in Python 3.5.2 requires str
  
      ff0string = str(stdout,'utf-8')
  
  
  
      ffinfo = json.loads(ff0string)
  
      print(json.dumps(ffinfo, indent=4)) # pretty print
  
  
  
      print("Video Dimensions: {}x{}".format(ffinfo["streams"][0]["width"], ffinfo["streams"][0]["height"]))
  
      print("Streams Duration:", ffinfo["streams"][0]["duration"])
  
      print("Format Duration: ", ffinfo["format"]["duration"])

  Results in output :

      ffprobe.cmd: ffprobe -loglevel quiet -sexagesimal -of json -show_entries stream=width,height,duration -show_entries format=duration -select_streams v:0 -i myvideo.mp4
  
      {
  
          "streams": [
  
              {
  
                  "duration": "0:00:32.033333",
  
                  "width": 1920,
  
                  "height": 1080
  
              }
  
          ],
  
          "programs": [],
  
          "format": {
  
              "duration": "0:00:32.064000"
  
          }
  
      }
  
      Video Dimensions: 1920x1080
  
      Streams Duration: 0:00:32.033333
  
      Format Duration:  0:00:32.064000

  UPDATE after several days of experimentation : The hachoire solution as proposed by Nick below does work, but will give you a lot of headaches, as the hachoire responses are too unpredictable. Not my choice.

  With opencv coding couldn’t be any easier :

  import cv2
  
  vid = cv2.VideoCapture( picfilename)
  
  height = vid.get(cv2.CAP_PROP_FRAME_HEIGHT) # always 0 in Linux python3
  
  width  = vid.get(cv2.CAP_PROP_FRAME_WIDTH)  # always 0 in Linux python3
  
  print ("opencv: height:{} width:{}".format( height, width))

  The problem is that it works well on Python2 but not on Py3. Quote : "IMPORTANT NOTE : MacOS and Linux packages do not support video related functionality (not compiled with FFmpeg)" (https://pypi.python.org/pypi/opencv-python).

  On top of this it seems that opencv needs the presence of the binary packages of FFmeg at runtime (https://docs.opencv.org/3.3.1/d0/da7/videoio_overview.html).

  Well, if I need an installation of FFmpeg anyway, I can stick to my original ffmpy example shown above :-/

  Thanks for the help.

  UPDATE2 : master_q (see below) proposed MediaInfo. While this failed to work on my Linux system (see my comments), the alternative of using pymediainfo, a py wrapper to MediaInfo, did work. It is simple to use, but it takes 4 times longer than my initial ffprobe approach to obtain duration, width and height, and still needs external software, i.e. MediaInfo :

  from pymediainfo import MediaInfo
  
  media_info = MediaInfo.parse("myvideofile")
  
  for track in media_info.tracks:
  
      if track.track_type == 'Video':
  
          print("duration (millisec):", track.duration)
  
          print("width, height:", track.width, track.height)

  UPDATE3 : OpenCV is finally available for Python3, and is claimed to run on Linux, Win, and Mac ! It makes it really easy, and I verfied that external software - in particular ffmpeg - is NOT needed !

  First install OpenCV via Pip :

  pip install opencv-python

  Run in Python :

  import cv2
  
  cv2video = cv2.VideoCapture( videofilename)
  
  height = cv2video.get(cv2.CAP_PROP_FRAME_HEIGHT)
  
  width  = cv2video.get(cv2.CAP_PROP_FRAME_WIDTH) 
  
  print ("Video Dimension: height:{} width:{}".format( height, width))
  
  
  
  framecount = cv2video.get(cv2.CAP_PROP_FRAME_COUNT ) 
  
  frames_per_sec = cv2video.get(cv2.CAP_PROP_FPS)
  
  print("Video duration (sec):", framecount / frames_per_sec)
  
  
  
  # equally easy to get this info from images
  
  cv2image = cv2.imread(imagefilename, flags=cv2.IMREAD_COLOR  )
  
  height, width, channel  = cv2image.shape
  
  print ("Image Dimension: height:{} width:{}".format( height, width))

  I also needed the first frame of a video as an image, and used ffmpeg for this to save the image in the file system. This also is easier with OpenCV :

  hasFrames, cv2image = cv2video.read()   # reads 1st frame
  
  cv2.imwrite("myfilename.png", cv2image) # extension defines image type

  But even better, as I need the image only in memory for use in the PyQt5 toolkit, I can directly read the cv2-image into an Qt-image :

  bytesPerLine = 3 * width
  
  # my_qt_image = QImage(cv2image, width, height, bytesPerLine, QImage.Format_RGB888) # may give false colors!
  
  my_qt_image = QImage(cv2image.data, width, height, bytesPerLine, QImage.Format_RGB888).rgbSwapped() # correct colors on my systems

  As OpenCV is a huge program, I was concerned about timing. Turned out, OpenCV was never behind the alternatives. I takes some 100ms to read a slide, all the rest combined takes never more than 10ms.

  I tested this successfully on Ubuntu Mate 16.04, 18.04, and 19.04, and on two different installations of Windows 10 Pro. (Did not have Mac avalable). I am really delighted about OpenCV !

  You can see it in action in my SlideSorter program, which allows to sort images and videos, preserve sort order, and present as slideshow. Available here : https://sourceforge.net/projects/slidesorter/

• vf_scale_vaapi : Add options to configure output colour properties

  28 février 2019, par Mark Thompson

  vf_scale_vaapi : Add options to configure output colour properties
  The "out_color_matrix" and "out_range" properties match the same options
  
  in vf_scale ; the others attempt to follow the same pattern.
  

  • [DH] libavfilter/vf_scale_vaapi.c

• lavfi/vaapi : Improve support for colour properties

  28 février 2019, par Mark Thompson

  lavfi/vaapi : Improve support for colour properties
  Attempts to pick the set of supported colour properties best matching the
  
  input.  Output is then set with the same values, except for the colour
  
  matrix which may change when converting between RGB and YUV.
  

  • [DH] libavfilter/vaapi_vpp.c
  • [DH] libavfilter/vaapi_vpp.h
  • [DH] libavfilter/vf_deinterlace_vaapi.c
  • [DH] libavfilter/vf_misc_vaapi.c
  • [DH] libavfilter/vf_procamp_vaapi.c
  • [DH] libavfilter/vf_scale_vaapi.c
  • [DH] libavfilter/vf_transpose_vaapi.c