aformat

Set output format constraints for the input audio. The framework will negotiate the most appropriate format to minimize conversions.

It accepts the following parameters:

'sample_fmts'

A '|'-separated list of requested sample formats.

'sample_rates'

A '|'-separated list of requested sample rates.

'channel_layouts'

A '|'-separated list of requested channel layouts.

See (ffmpeg-utils)the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.

If a parameter is omitted, all values are allowed.

Force the output to either unsigned 8-bit or signed 16-bit stereo

aformat=sample_fmts=u8|s16:channel_layouts=stereo