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• Compression of a video with constant background

  28 juin 2017, par Spirou003

  (sorry if my english is bad, I can read it but I don’t write it quite well...)

  I want to compress some videos, which have two particularities :

  • there is a background that covers 90% of the area, during the whole video
  • most of the others elements can be separately described by a picture in move

  My videos are like this one, and don’t have audio. As you can see, almost everything can be described only by using a fixed background, few small images in move, plus a noise. Moreover, this noise will be almost nul and then an entropic coding would be very efficient. I think it will produce tiny files (< 5 Mo) even if the duration is in hours, a result that is very appreciable since I have actually recorded 30h of game (actual size is 3 Go).

  Is there any way to get new video files, that benefit of these informations ? If yes, what are the implication of a such encoding for watching these videos with Windows Media Player, or for usage with ffmpeg ?

  I searched with Google after anything that can help me, but I don’t know which keyword I can use for this, then I didn’t found anything usefull :-(

  Thanks in advance :-)

  PS : another example, the video is accelerated but shows the interesting moves

• In some cases, the value of FFmpegMSS is null

  16 février 2018, par Sanhei

  Uri uri = new Uri("https://cloud189-nj.oos-js.ctyunapi.cn/68e09e6a-3a50-4f7b-ba59-968d61dcb771?response-content-type=video/mp4&Expires=1518683112&response-content-disposition=attachment%3Bfilename%3D%22%5BUHA-WINGS%5D%5BKakegurui%5D%5B01%5D%5B720p%5D%5BGB%5D.mp4%22&AWSAccessKeyId=ad2d051c334eb8bbf4c1&Signature=22RXF7qDozpBQNl44/QVx62Anv4%3D");
  
  var FFmpegMSS = FFmpegInteropMSS.CreateFFmpegInteropMSSFromUri(uri, true, true);

  When the value of uri is "http://edge.ivideo.sina.com.cn/31451018.flv?KID=sina,viask&Expires=1518796800&ssig=7zn7dHMQVK",the program can run normally

  What is the difference between them ?
  How do I modify the code to make ffmpeg work properly ?

  My English is not good, I’m sorry for the inconvenience.

• using ffmpeg to resize video with black bars

  23 juillet 2018, par Jens S

  i have a video with resolution 720:576 and i want it to have the ratio 16:9, e.g. 1024:576 with black bars on the sides. don’t know if it matters, but i am working with ffmpeg for windows. After research i tried the solution i found on 2 related questions :

  -i .\video.mp4 -vf scale=1024:576:force_original_aspect_ratio=decrease,pad=1024:576:(ow-iw)/2:(oh-ih)/2,setsar=1 out.mp4

  but i get an output that "ow-iw" was not recognized. Here is the complete output. unfortunatly it is in german(as am i) if u tell me how to change the output language i will provide it in english :

  ow-iw : Die Benennung "ow-iw" wurde nicht als Name eines Cmdlet, einer Funktion, einer Skriptdatei oder eines ausführbaren Programms erkannt. Überprüfen Sie die Schreibweise des
  
  Namens, oder ob der Pfad korrekt ist (sofern enthalten), und wiederholen Sie den Vorgang.
  
  In Zeile:1 Zeichen:119
  
  + ... :576:force_original_aspect_ratio=decrease,pad=1024:576:(ow-iw)/2:(oh- ...
  
  +                                                             ~~~~~
  
      + CategoryInfo          : ObjectNotFound: (ow-iw:String) [], CommandNotFoundException
  
      + FullyQualifiedErrorId : CommandNotFoundException