[FFmpeg-user] 'mix=nb_inputs=2' provokes error...

[Mark Filipak (ffmpeg)]

...contrary to https://ffmpeg.org/ffmpeg-filters.html#mix

[Parsed_mix_29 @ 0000025771c709c0] Option 'nb_inputs' *not found*
[AVFilterGraph @ 0000025772b53dc0] Error initializing filter 'mix' with args 'nb_inputs=2:weights=3 2'
Error initializing complex filters.
Option not found