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• error when running "imageio.plugins.ffmpeg.download()"

  14 juin 2018, par Maryeveh

  I am trying to run the command imageio.plugins.ffmpeg.download() after installing moviepy and imageio and importing imageio without error.
  I keep getting the following error and cannot figure out the solution :

  Imageio: 'ffmpeg-osx-v3.2.4' was not found on your computer; downloading it now.
  
  Error while fetching file: <urlopen error="error" certificate="certificate" verify="verify" failed="failed">.
  
  Error while fetching file: <urlopen error="error" certificate="certificate" verify="verify" failed="failed">.
  
  Error while fetching file: <urlopen error="error" certificate="certificate" verify="verify" failed="failed">.
  
  Error while fetching file: <urlopen error="error" certificate="certificate" verify="verify" failed="failed">.
  
  
  
      ---------------------------------------------------------------------------
  
      IOError                                   Traceback (most recent call last)
  
       in <module>()
  
            3 get_ipython().magic(u'matplotlib inline')
  
            4 import imageio
  
      ----> 5 imageio.plugins.ffmpeg.download()
  
            6 import matplotlib
  
            7 import matplotlib.pyplot as plt
  
  
  
      /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/imageio/plugins/ffmpeg.pyc in download(directory, force_download)
  
          71     get_remote_file(fname=fname,
  
           72                     directory=directory,
  
      ---> 73                     force_download=force_download)
  
          74 
  
          75 
  
  
  
      /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/imageio/core/fetching.pyc in get_remote_file(fname, directory, force_download, auto)
  
        125             return filename
  
         126     else:  # pragma: no cover
  
     --> 127         _fetch_file(url, filename)
  
         128         return filename
  
         129 
  
  
  
      /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/imageio/core/fetching.pyc in _fetch_file(url, file_name, print_destination)
  
          181         raise IOError('Unable to download %r. Perhaps there is a no internet '
  
          182                       'connection? If there is, please report this problem.' %
  
      --> 183                       os.path.basename(file_name))
  
          184 
  
          185 
  
  </module></urlopen></urlopen></urlopen></urlopen>

  IOError : Unable to download ’ffmpeg-osx-v3.2.4’. Perhaps there is a
  no internet connection ? If there is, please report this problem.

  I tried all the solutions I could think of or/and found online, including the ones described here ffmpeg installation on macOS for MoviePy fails with SSL error, but nothing helped.
  Does anyone found another solution ?

  Thanks

• Merging audio channels by FFmpeg libraries C++

  13 juin 2023, par Elija

  C/C++ project. There are several audio tracks with an individual number of channels. Each is processed using a avresampler. The avresampler converts all tracks to the same format. At the output of the avresampler, we get a set of channels from all audio tracks. Do the FFmpeg libraries have any standard means to merge all these audio channels into another set of audio channels using AVFrame::ch_layout to form a single audio track ? That is, no additional processing is required, except for copying channels buffers from several AVFrames of different audio tracks to new positions of one AVFrame according to the new layout and aligning the timestamps of different audio tracks, since different audio tracks can have audio frames of different sizes with different timestamps.

  


  For example, 1 audio track with 2 channels and 2 audio tracks with 6 channels will be merged into 16 channels with silence in the "missing" channels. Or 4 audio tracks with 2 channels merged into 8 channels. Etc...

  


  Is there a way to use a avresampler for this ? Or a avfilter ? Or something else ?

  


  Any source code or any reading source that can help me is welcome.

  


• ffmpeg create thumbnail image of multiple images from video

  21 janvier 2018, par Michael Yousef

  So I want to create a thumbnail image that consists of multiple images from a single video. I’m looking to make them 4x8, and I want to spread out the images uniformly throughout the video.

  Ideally the final product should show 32 image captures, all downscaled to a reasonable size so they can fit on screen at the same time. Also, I’d like to have the final product have some overhead text like the video title, and I’d like to put the timestamp in the images as well.

  

  This is an example of what I want to do. The text at the top and the timestamp in the images. This one’s 6x4 and I want 4x8 but other than that it looks about what I want.

  I think ffmpeg probably has something to do this but I can’t seem to figure it out. I can generate individual screens but not collapse them into one. It’s also slower than programs I’ve used to do this in the past, not sure how they can do it as fast as they do. If I can’t get ffmpeg to do this, I’m open to using Python to accomplish this.