High CPU usage

[varac]

I noticed that wlstreamer eats nearly 100% of my CPU:

 167314 varac     20   0  377896 108780  96172 S  55,5   0,9   0:12.48 wf-recorder                                                                                                        
 167316 varac     20   0  288032  63316  40468 R  51,5   0,5   0:11.37 ffmpeg   

Together with jitsi which is also super CPU intensive my Laptop is on it's limits.
I saw ammen99/wf-recorder#77 related to CPU issues, can you think of any other possible improvement besides reducing screen resolution ?

[b12f]

We could think about having an option to only show that active application instead of the full screen; #1 asked for this. This might reduce wf-recorder load, but it will not reduce ffmpeg load, instead now requiring it for every possible input stream. Perhaps also possible would be to reduce the framerate, at least on the ffmpeg side.

[b12f]

Another would be to do the recording manually instead of via wf-recorder, with https://github.com/Smithay/wayland-rs that way the adding of black borders to smaller resolutions could be done all-in-one instead of writing through two loopback devices.

However, as said, I'm a noob when it comes to rust, even more when it comes to video, and have never even seen a Wayland api, so this would be a holiday project if I ever have time and feel like doing it.

[b12f]

With ammen99/wf-recorder#133 we might be able to reduce the load a bit, since we won't have to juggle two different video streams for nonmatching resolutions