Pan all audio center channels in ffmpeg?

I use FFMPEG to transcode a large file to a smaller file. Typically, files will have 2 audio channels (although not always). I'm trying to focus all the audio channels.

I asked 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 answers is that FFMPEG has not yet implemented sound filters. Somehow I had to create a filter libav To pan of all channels in the heart of ... something like (?) pan="c0=0.5*FL+0.5*FR", But when I do it, I get an error: No such filter: 'pan'. These guys are great, but I can't figure it out by reading the docs .

I have no disabled filters, here is my assembly information 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-in commands: ffmpeg -i inMovie.mov -acodec libfaac -ab 64k -vcodec libx264 -vpre medium -b 320k -pass 1 -s 374x210 -threads 0 outMov.mp4

I have the rest of my FFMPEG command line working fine ... Essentially, I'm looking for the left / right audio channels to have the same sound in the output file. If there is an easier way to do this (convert to 2 mixed mono channels?) I'm all ears!

Thank you for your help!

+3
source share
2 answers

Sound filters have different syntax on FFMPEG. You can pan the audio channels without creating a mix.

Using your example:

ffmpeg -f lavfi -i "amovie=inMovie.mov,pan=stereo: c0=c0+c1: c1=c0+c1" -i inMovie.mov -map 0:0 -map 1:0 -vcodec libx264 -vpre medium -b 320k -pass 1 -s 374x210 -threads 0 -acodec libfaac -ab 64k outMov.mp4
+2
source

At the moment, I don’t have a link to the command, but I would use FFMPEG to mix in mono and then convert back to stereo. This should give you the results you need.

0
source

All Articles