[FFmpeg-user] Mixing audio tracks

Nicolas George nicolas.george at normalesup.org
Wed May 23 11:13:36 CEST 2012

Le quintidi 5 prairial, an CCXX, Andrey Utkin a écrit :
> First i tried with recently added -af flag, but it looks unclear how
> to address different input files, and is it is possible at all. See
> Listing 1.

-af works only for a single input and a single output. For several inputs or
outputs, you need to use -filter_complex.

> Then i tried -f lavfi, but having confusion about usability of it.
> amerge filter tells on merging two mono files "Inputs overlap: output
> layout will be meaningless".

That is probably normal, since your source tracks have the same channels.

> LD_LIBRARY_PATH=. ./ffmpeg -f lavfi -i
> "amovie=/home/krieger_nocrypt/music/Iron_Maiden/Brave_new_world/05-out_of_the_silent_planet.mp3,pan=1
> [a0]; amovie=/home/krieger_nocrypt/music/Iron_Maiden/Brave_new_world/04-ghost_of_the_navigator.mp3,pan=1
> [a1]; [a0][a1] amerge,pan=1" -codec libfaac -y /tmp/amerge.flv
> -loglevel debug

> Segmentation fault (core dumped)

That should not have happened. I will try to look into it shortly.


  Nicolas George

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