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• Can I use FFMPEG to losslessly merge three audio and video files and keep all of the streams for an. mp4 file ?

  26 décembre 2022, par AmalgamAsh

  I regularly use video editing software and use a few lines of FFMPEG to do some work on the files before I get to them.

  


  I don't understand FFMPEG that well, and am trying to see if it is possible to do what I want, which is create a single video file that has two video streams (from two synced sources - for example, screen capture and facecam footage from another device).

  


  What I usually end up with after recording is this :

  


  File 1 :

  


  

  • Screencapture video

  


  • PC default audio

  


  


  File 2 :

  


  

  • Face cam footage

  


  • Face cam audio capture

  


  


  File 3 :

  


  

  • Microphone audio captured independently

  


  


  and what I would like to end up with is this :

  


  File 1 :

  


  

  • facecam video

  


  • screencapture video

  


  • PC default audio

  


  • Face cam audio capture

  


  • Microphone audio

  


  


  I'd really like to have this in an .mp4 and then, hopefully, adobe premiere can open it and display the separate video tracks. As for the video footage, I would be resizing the face cam footage, placing it "on top of" the screen capture layer in premiere, and syncing the audio sources before getting rid of the face cam audio. As such, I don't want to display the videos side-by-side or vertically — just overlaid (I guess if the video result was viewed as-is, the viewer would only be able to see the "top" layer, right ? But this is fine, as I'd be using this file to edit a new video).

  


  I'm willing to try and extrapolate any examples anyone can give me of how to do this ; I've tried altering and playing with other FFMPEG examples here and have gotten the simplest ones to work but so far have had no luck with this more complex process.

  


  Here is the code I've tried to use, and endless variations of it, to no avail.
I am sure the mistake is glaring at me clearly but I just haven ;t been able to wrap my head around the simplest of explanations that explain how to use FFMPEG.
used in conjunction with batch :

  


  ffmpeg -i %file1% -i %file2% -i %file3% -map 0:v -map 1:a:0 -map 0:a:0 -map 2:v -c copy %outputfile%


  


• Anomalie #2729 : titre mot

  6 décembre 2012, par realet RealET

  Voir aussi http://core.spip.org/issues/2862 qui porte sur les id au lieu des titres des mots.

• Converting png images series to webm with transparent white background from Daz3d

  25 août 2015, par James

  I’m trying to make a webm video with a transparent background from a Daz3D model.
  My process is export png image series with transparent background from Daz3D, use ffmpeg to convert png series to webm video.
  This was working well in Daz3D 4.6.

  But in Daz3D 4.8 the exported background is black instead of white, so when converted to webm is ok on Chrome as has the transparency, but on Firefox is black and has a halo (as Firefox does not support transparency so displays background).

  So I’m looking for a solution with Daz3D, or tools like ImageMagik.
  I almost got it with ImageMagik,

  convert -alpha extract *.png mask.png
  
  mogrify -flatten talk*.png
  
  for /f %x in ('dir /s /b blink*.png') do @composite -compose CopyOpacity mask-0.png %x %x

  But for some reason the final webm has a white background not transparent ...
  Some more info here,

  http://www.daz3d.com/forums/discussion/61237/daz3d-4-8-png-background-is-black

  and here,

  http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=28214

  >
  Doh, okay I figured it out. My images were good, but I somehow have two different versions of ffmpeg on my computer and was using the wrong one that doesn’t seem to support transparency.

  Now it is working.

  My only issue is the last shell line,

  for /f %x in (’dir /s /b blink*.png’) do @composite -compose CopyOpacity mask-0.png %x %x

  This only uses mask-0.png, instead of mask-1 for blink01.png, mask-2 for blink02.png etc.