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• 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])

• 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.

  


• Curator of the Samples Archive

  13 mai 2011, par Multimedia Mike — General

  Remember how I mirrored the world-famous MPlayerHQ samples archive a few months ago ? Due to a series of events, the original archive is no longer online. However, me and the people who control the mplayerhq.hu domain figured out how to make samples.mplayerhq.hu point to samples.multimedia.cx.

  That means... I’m the current owner and curator of our central multimedia samples repository. Such power ! This should probably be the fulfillment of a decade-long dream for me, having managed swaths of the archive, most notably the game formats section.

  How This Came To Be

  If you pay any attention to the open source multimedia scene, you might have noticed that there has been a smidge of turmoil. Heated words were exchanged, authority was questioned, some people probably said some things they didn’t mean, and the upshot is that, where once there was one project (FFmpeg), there are now 2 projects (also Libav). And to everyone who has wanted me to mention it on my blog— there, I finally broke my silence and formally acknowledged the schism.

  For my part, I was just determined to ensure that the samples archive remained online, preferably at the original samples.mplayerhq.hu address. There are 10 years worth of web links out there pointing into the original repository.

  Better Solution

  I concede that it’s not entirely optimal to host the repository here at multimedia.cx. While I can offer a crazy amount of monthly bandwidth, I can’t offer rsync (invaluable for keeping mirrors in sync), nor can the server provide anonymous FTP or allow me to offer accounts to other admins who can manage the repository.

  The samples archive is also mirrored at samples.libav.org/samples. I understand that service is provided by VideoLAN. Right now, both repositories are known to be static. I’m open to brainstorms about how to improve the situation.