Does the desired number of channels in audio output have to be selected each time, or does the device remember user's choice?

Yes, the device will remember the user's last selection.

Questions & Answers: HDMI Switch with Audio Extractor 4K 60Hz Optical + 3.5mm AUX + Coaxial Output, HDMI Switcher 4 in 1 Out HDMI Audio Splitter Converter IR Remote Support ARC HDCP2.2 1080P 3D Dobly Atmos,EDID,HDR10

double click image to zoom in

Top Rated Visit ESTONE Store

HDMI Switch with Audio Extractor 4K 60Hz Optical + 3.5mm AUX + Coaxial Output, HDMI Switcher 4 in 1 Out HDMI Audio Splitter Converter IR Remote Support ARC HDCP2.2 1080P 3D Dobly Atmos,EDID,HDR10

There are 4 ports HDMI input,1 port HDMI output, Toslink output, Coaxial Output, L/R output HDMI output port with ARC function
Support 480i / 480p / 576i / 576p / 720p@50/60Hz / 1080p@50/60Hz / 4Kx2K@20/30Hz/60Hz with 36bit RGB / YcbCR 4:4:4 / (4k@60hz RGB8:8:8)
Max bandwidth per channel: 600MHz ; Max baud rate per display: 18Gbps; Compliant with HDMI2.0b, HDCP2.2 /1 .4 /1.3 /1.2/1.1
HDMI input and output hdmi 2.0b cables can reach up to 3 meters if your Resoltion up to 4K@60HZ; can reach up to 5 meters if your Resolution up to 4K@30HZ
Support 24/30/36 bit deep color per channel (Kindly Note: It is can not compatible with DVI. We do not recommended that you use HDMI to DVI cable connect to your projector /monitor)

$42^.99 –