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• FFMpeg Speed up transparent webm C#/Cmd

  17 avril 2023, par Alphapixel 182004

  I am trying to speed up a webm video file while maintaining the transparency but every attempt I've made has removed the transparency.

  


  How do I speed up a transparent webm using FFMpeg without losing the transparency ?

  


  Note : I am doing this all in c# but would prefer to use commands instead of wrapper libraries.

  


  this is the general command I have tried :

  


  command = $"-i \"{input}\" -filter_complex \"[0:v]setpts = (1/{speed}) * PTS[v]; [0:a]atempo = {speed}[a]\" -map \"[v]\" -map \"[a]\" -c:v libvpx-vp9 -b:v 1M -y \"{output}";
That command did not maintain transparency though.

  


  A little info about the input video :

  


  


  • The input is transparent

    


  


  • the input is basically a mess of individual transparent webm's joined together that were made with either :

    


    

    • Poster with audio :

    


    


  


  


  $"-threads 4 -loop 1 -i \"{image}\" -i \"{audio}\" -c:v libvpx-vp9 -pix_fmt yuva420p -crf 10 -b:v 0 -c:a libopus -b:a 192k -shortest -movflags +faststart -y \"{output}\"";

  


  

  • Padding the clip :

  


  


  $"-i \"{input}\" -filter_complex \"[0:v]split=2[v1][v2];[v1]tpad=start_duration={startPadMs / 1000}:start_mode=clone:stop_duration={endPadMs / 1000}:stop_mode=clone[v1_edited];[v1_edited][v2]overlay=eof_action=pass[v];[0:a]adelay={startPadMs}|{startPadMs}[a]\" -map \"[v]\" -map \"[a]\" \"{output}\""

  


  

  • Joining videos :

  


  


  var temp = Path.Combine(Path.GetTempPath(), "concat.txt"); File.WriteAllText(temp, string.Join('\n', clips.Select(e => $"file '{e}'"))); var command = $"-f concat -safe 0 -i "{temp}" -c copy -y "{output}"";\

  


• lavu : add an API function to return the FFmpeg version string

  30 juin 2015, par wm4

  lavu : add an API function to return the FFmpeg version string
  This returns something like "N-73264-gb54ac84". This is much more useful
  
  than the individual library versions, of which there are too much and
  
  which are very hard to map back to releases or git commits.
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/APIchanges
  • [DH] libavutil/avutil.h
  • [DH] libavutil/utils.c

• Can I get pictures/stills/photos from inside a container file from a CD-I disc ?

  8 décembre 2017, par user9047197

  I have ffmpeg setup.

  Is there a way to extract pictures/stills/photos (etc) from a container (file) that’s from an old CD-I game that I have.

  I don’t want to extract the audio nor video. And I don’t want frames from the videos either.

  I want the bitmaps (etc) from INSIDE that container file.

  I know my Windows 8.1 PC can’t read inside that container file - so I’m hoping there’s a way to extract all the files (I want) instead using ffmpeg.

  (IsoBuster only gives the audio and video so I know already about IsoBuster.)

  I think there are no individual headers for the pictures/stills/photos, etc.

  Here’s what ExifTool decoded the file as :

  ExifTool Version Number (10.68) 
  
  File Name (green.3t) 
  
  File Size (610 MB) 
  
  File Permissions (rw-rw-rw-) 
  
  File Type (MPEG) 
  
  File Type Extension (mpg) 
  
  MIME Type (video/mpeg) 
  
  MPEG Audio Version (1) 
  
  Audio Layer (2) 
  
  Audio Bitrate (80 kbps) 
  
  Sample Rate (44100) 
  
  Channel Mode (Single Channel) 
  
  Mode Extension (Bands 4-31)
  
  Copyright Flag (False) 
  
  Original Media (False) 
  
  Emphasis (None) 
  
  Image Width (368)
  
  Image Height (272) 
  
  Aspect Ratio (1.0695) 
  
  Frame Rate (25 fps) 
  
  Video Bitrate (1.29 Mbps) 
  
  Duration (1:02:12 approx) 
  
  Image Size (368x272) 
  
  Megapixels (0.100) 

  Thank you for reading and - help !! :D