# ffserver >/dev/null 2>&1 &
 # ffmpeg -video_size 1600x900 -framerate 25 -f x11grab -i :0.0 -f alsa
   -ac 2 -i hw:0 http://localhost:8090/feed1.ffm

[mpeg1video @ 0x55652e5d5da0] MPEG-1/2 does not support 3/1 fps
...
Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height