Recherche avancée

Sur d’autres sites (12689)

• Generate valid ASF file for WMAsfReader

  3 février 2020, par user6380706

  My legacy software breaks after migrating it to Windows 10 since WMV Encoder 9 SDK isn’t longer supported.

  I’ve tried other approaches, and I can generate the ASF file I need using FFmpeg.
  I only need mux audio and video into ASF container, and this command do it :

  ffmpeg -y -i audio.mp3 -i video.asf -vcodec copy -acodec copy output.asf

  It works well, and the file can be played using VLC or Windows Media Player.
  But it can’t be played by DirectShow. I’ve got a ASF_E_INVALIDHEADER error when I set as the source of WMAsfReader. Any idea how can I generate a valid ASF file for the WMAsfReader ?

  Thnks !

• jpeg2000dec : assert that curtileno is valid when used

  3 juin 2013, par Michael Niedermayer

  jpeg2000dec : assert that curtileno is valid when used
  Fixes CID1026755
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/jpeg2000dec.c

• FFMPEG Determine average color of an area of a video

  12 novembre 2019, par Naved Khan

  I have a use case where I’d want to insert one of two watermarks - one designed for a dark-ish background, the other for a light background into a video. Let’s say that I’d want to do this on the top right corner of the video.

  How do I determine the average color of the top right section of the video ? Post this, how do I determine which watermark to use by looking at the average color ?

  I have a solution right now where I am taking equally spaced screenshots and then measuring the average color, but it’s excruciatingly slow, especially for longer videos.

  # Calculate average color
  
      black_distances = []
  
      white_distances = []
  
  
  
      movie = FFMPEG::Movie.new(video_file)
  
      (0..movie.duration / 10).each do |second|
  
  
  
        # extract a frame
  
        filename = "tmp/watermark/#{SecureRandom.uuid}.jpg"
  
        movie.screenshot filename.to_s, seek_time: second
  
  
  
        # analyse frame for color distance
  
        frame = MiniMagick::Image.open(filename)
  
        frame.crop('20%x20%+80%+0')
  
        frame.resize('1x1')
  
        pixel = frame.get_pixels.flatten
  
  
  
        distance_from_black = Math.sqrt(((black[0] - pixel[0])**2 + (black[1] - pixel[1])**2 + (black[2] - pixel[2])**2))
  
        distance_from_white = Math.sqrt(((white[0] - pixel[0])**2 + (white[1] - pixel[1])**2 + (white[2] - pixel[2])**2))
  
  
  
        black_distances.push distance_from_black
  
        white_distances.push distance_from_white
  
  
  
        File.delete(filename) if File.exist?(filename)
  
      end
  
  
  
      average_black_distance = black_distances.reduce(:+).to_f / black_distances.size
  
      average_white_distance = white_distances.reduce(:+).to_f / white_distances.size

  I am also confused about how to use the resulting average_black_distance and average_white_distance to determine which watermark to use.