I'm just not sure how to use the terminal to change the Desktop's active resolution without a reboot. I'm not sure if I should be looking for a way to change the framebuffer resolution, or X Server's resolution, or the Desktop Environment's resolution, or all of the above.
From my understanding, the Raspberry Pi GPU resolution is completely unrelated to the ...
It will be enough, but the performance will depend on the codec used:
HEVC, H.265 and H.264 are supported in hardware, so those will offer the best performance with a compatible video player such as VLC.
Older formats such as MPEG-2 are decoded in software, which is fine in most cases. Videos with high bitrates (such as Blu-ray) will result in significant ...
It is very good question, on rpi 1-2-3 i use special license keys to unlock hardware ecoding MPEG-2 and VC-1. But on rpi4 hardware decoding of MPEG-2 and VC-1 not supported.
I don't know what you mean by "HDMI hot-pluggable" (or indeed what the Foundation setting actually means by the parameter in config.txt).
I take your question to mean can you change the resolution post boot.
Normally the resolution (and other display settings) is set on boot and inherited by GUI.
It is theoretically possible to select a display mode with ...
Those are explained here: https://www.raspberrypi.org/documentation/configuration/config-txt/video.md
There is also this: https://www.raspberrypi.org/documentation/configuration/hdmi-config.md -- But if the group 1, mode 16 as above works, you don't have to worry about all that.
Having experimented with a virgin SD card install, I confirm Dougie's comment above: the default is HDMI, but if an HDMI monitor is absent, it falls back to using composite output.
I cannot yet explain why this doesn't seem to be the case for my OSMC installation. As such, the question is arguably in the wrong forum!