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• FFmpeg : Issues for Transparent Background in WebM Video [closed]

  20 juillet 2024, par BlueSky

  I've encountered an issue while processing videos with FFmpeg. I want to convert a MOV video with an alpha channel to WebM format and overlay it onto a main video. Below are the steps I took and the problem I encountered.

  


  I used Adobe After Effects (AE) to remove the green screen background from a video and exported the MOV file with RGB+Alpha channels using the Animation codec. Additionally, I tried exporting in QuickTime format, both ensuring the alpha channel was included.

  


  When converting the MOV video to WebM format, I executed the following command :

  


  ffmpeg -i input.mov -c:v libvpx-vp9 overlay.webm


  


  Then, I attempted to overlay the converted WebM video onto the main video main.mp4 using the following command :

  


  ffmpeg -i main.mp4 -vf "movie=overlay.webm,scale=200x200[video_inner];[in][video_inner]overlay=x=10:y=10[out]" output.mp4


  


  However, in the final output.mp4 video, the background of the WebM video was not transparent as expected, but instead showed a black background after removing the green screen.

  


  Could there be an error in one of my steps ?

  


  I have tried different command parameters and options but have not been able to resolve this issue.

  


  I expected the WebM video to retain its transparent background when overlaid onto the main video. However, the resulting output.mp4 video showed the background of the WebM portion as black instead of transparent.

  


• Python convert audio files to MP3

  19 janvier 2015, par Fernando Retimo

  I’m trying to write a small utility that get as input an m4a/ogg file and converts it to a MP3 audio file.
  My main goal is not to use any third party binaries such as ’Lame’ or ’ffmpeg’.
  I read allot about PyMedia and such, but my knowledge on audio codecs is very poor.
  Can any one help me and give me an elegant cross platform solution ?
  Thanks !

  EDIT :
  meanwhile I know it is very basic but this is my code :

  import sys
  
  
  
  def convert2mp3(input_file):
  
      .....
  
      some magic...
  
      ...
  
      return mp3file
  
  
  
  if __name__ == "__main__":
  
      if len(sys.argv) != 2:
  
          print "%prog Usage: %s <input file="file" />"
  
          sys.exit()
  
  
  
      convert2mp3(sys.argv[1])

• Move all files from a folder EXCEPT those still in use (by other processes like ffmpeg)

  9 janvier 2019, par juzzle

  I am cleaning up a series of MP4 files using FFMPEG. I want to create a simple bat file script which moves the completed files (which are those which have a duration value), not the stubs of files in progress. This is the basic structure :

  set SourcePath=C:\Source Folder
  
  pushd %SourcePath%
  
  move *.MP4 C:\Finished Folder

  What options are available to use in the MOVE command to supress the moving of those files still in use by FFMPEG ?

  I did consider Robocopy’s /minage or /minlad option for this, but the minimimum incremenent is DAYS, not seconds.