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• ffmpeg : Crop webm file with circular .png mask [closed]

  26 mars 2021, par Beneos Battlemaps

  I tried everything for hours and can get it working by myself. I want to create animated Pen&Paper tokens for virtuale tabletops. I have a .webm video file with 720x720 pixel showing an animation of a render file created out of a png sequence via

  


  ffmpeg -framerate 24 -f image2 -i face.%04d.png -c:v libvpx-vp9 -pix_fmt yuva420p face1.mp4

  


  See here : https://webmshare.com/play/ZxZa0

  


  Now i want to overlay this .webm with an circle image as frame :

  


  overlay

  


  and crop the black part so its transparent in the end result as well as keeping the transparent area in the center for the video itself.

  


  So the endresult is from this :

  


  Face1

  


  to this :

  


  Face2

  


  Can you help me out with that ? If its easier i can split the steps, making first the alpha mask crop via png and adding the circle in it later.

  


  Beste regards in advance
-Ben

  


• Graph-based video processing for .NET

  23 octobre 2016, par Borv

  Does anyone know a good object-oriented library (preferably high-level, like C# or Java) for working with video and audio streams ?

  I wrote an app which fiddles with video and audio streams, feeds and such. The original task was simple :

  • grab an RTSP feed
  • display original feed(s) on the display
  • convert it to a series of h264 ts files
  • extract audio into separate MP3 files
  • upload videos and audio to the web site (preferably in real time, few minute delay is acceptable)

  As you may have already guessed it is about recording events (e.g. lectures) and publishing them on the web.

  To pull this out I needed some graph-based non-linear editing for media. Two weeks in, I tried ffmpeg, vlc and WMF. The only library I got to work is ffmpeg, and that comes with lots of "however". WMF required a lot of coding (and I abandoned this path), vlc looked great on paper, but I stumbled across some bugs with input splitting I could not get around (e.g. transcode:es combination flat out refused to work).

  So, the question. What are good non-linear editing libraries besides ffmpeg, vlc and wmf/directshow that allow for building video processing graphs with sources, sinks and filters ? Or perhaps good bindings over ffmpeg and vlc allowing to build such graphs ?

• Multimedia Exploration Journal : The Past Doesn’t Die

  12 juillet 2011, par Multimedia Mike — Game Hacking

  New haul of games, new (old) multimedia formats.

  Lords of Midnight
  Check out the box copy scan for Lords of Midnight in MobyGames. In particular, I’d like to call your attention to this little blurb :

  
  
  

  Ahem, "Journey through an immense world — the equivalent of 8 CD-ROMs." Yet, when I procured the game, it only came on a single CD-ROM. It’s definitely a CD-ROM (says so on the disc) and, coming from 1995, certainly predates the earliest DVD-ROMs (which can easily store 8 CD-ROMs on a disc). Thus, I wanted to jump in a see if they were using some phenomenal compression in order to squeeze so much info into 600 or so megabytes.

  I was surprised to see the contents of the disc clocking in at just under 40 megabytes. An intro movie and an outro movie account for 75% of that. Format ? None other than that curious ASCII anomaly, ARMovie/RPL with Escape 122 codec data.

  Cyclemania

  
  
  

  Cyclemania is one of those FMV backdrop action games, but with a motorcycle theme. I had a good feeling I would find some odd multimedia artifacts here and the game didn’t disappoint. The videos are apparently handled using 3-4 discrete files per animation. I’ve documented my cursory guesses and linked some samples at the new MultimediaWiki page.

  Interplay ACMP
  This is unrelated to this particular acquistion, but I was contacted today about audio files harvested from the 1993 DOS game Star Trek : Judgment Rites. The files begin with the ASCII signature "Interplay ACMP Data". This reminds me of Interplay MVE files which begin with the similar string "Interplay MVE File". My theory is that these files use the ACOMP compression format, though I’m still trying to make it fit.

  Wiki and samples are available as usual if you’d like to add your own research.