I am using FFMPEG to transcode a large file to a smaller file. Usually the files will have 2 audio channels (though not always). I am trying to center all audio channels.
I asked over at the ffmpeg-users for examples of how to do this: http://ffmpeg-users.933282.n4.nabble.com/Panning-audio-channels-example-td4417939.html
What I got from the replies is that FFMPEG has yet to implement audio filters. Somehow I should be able to set up a libav filter (?) to pan all channels center… something to the effect of:
pan="c0=0.5*FL+0.5*FR" though when I do this, I get the error: No such filter: 'pan'. Those guys are great but I can’t figure this out by reading the docs.
I have not disabled filters, here is my build info
configuration: --prefix=/opt/local --enable-gpl --enable-postproc --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libdirac --enable-libschroedinger --enable-libopenjpeg --enable-libxvid --enable-libx264 --enable-libvpx --enable-libspeex --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/opt/local/bin/gcc-apple-4.2 --arch=x86_64 --enable-yasm --enable-nonfree --enable-libfaac
Here is an example of one of my built command lines: ffmpeg -i inMovie.mov -acodec libfaac -ab 64k -vcodec libx264 -vpre medium -b 320k -pass 1 -s 374x210 -threads 0 outMov.mp4
I’ve got the rest of my FFMPEG command line working great… Essentially what I am looking for is to have left/right audio channels both have the same audio in the output file. If there is an easier way to do this (convert to 2 mixed mono channels?) I am all ears!!
Thank you for your help!
The audio filters have a different sintax on FFMPEG. You can pan audio channels without create a mixdown.
Using your example: