You have two methods:
-map_channel
You can use the -map_channel
option:
ffmpeg -i stereo.wav -map_channel 0.0.1 right_mono.wav
- The first
0
is the input file id - The next
0
is the stream specifier - The
1
is the channel id
So this can be translated as: first file, first stream, second channel (or right channel).
From the -map_channel
documentation:
The order of the
-map_channel
option specifies the order of the channels in the output stream. The output channel layout is guessed from the number of channels mapped (mono if one-map_channel
, stereo if two, etc.
pan
audio filter
You could also use the pan
audio filter:
ffmpeg -i stereo.wav -af pan=1:c0=c1 right_mono.wav
1
is output channel layout or number of channelsc0=c1
is the "outdef", or output channel specificationc0
represents the desired output channel numberc1
represents the input channel to use
Make sure to read the pan
documentation first.