Provide simple HDMI-CEC volume control

[waydabber]

Newer Macs (M3 MBPs with HDMI port and possibly the upcoming M4 macs) have working HDMI-CEC hardware and are enabled and accessible in newer macOS versions.

It might be useful to add a simple volume up/down HDMI-CEC control feature to the app and give the option to tie it to the volume up/down keyboard.

Standby control is already implemented natively in macOS for these devices (the connected TV and connected receivers can be put to standby mode and powered on display sleep if HDMI-CEC control is enabled) - so no need to add that feature.

[mklingberg]

Was just looking for this feature, would be great 👍

[waydabber]

Well, I need to do more research on the topic. I figured out what stuff should I use but it's rather complicated and of course there is no documentation at all (as it is an undocumented API). But will try to dive into this. However this requires hardware support and afaik only M3 MBPs support HDMI-CEC currently using the built-in HDMI port. Third party HDMI dongles and pre-M3 Macs won't work.