Right, I did some asking in #gstreamer about ways of switching video resolution on-the-fly but the news is not all that good.

First I'll see if I can change the filter caps to get the v4l2 device to change res on the fly, if this works then all's well and good and we can temporarily switch to higher res to send to the analysis code and use a videoscale element to downscale for display. But I have my doubts whether it will allow us to switch on the fly.

The videoscale element eats CPU, so we don't want to have to use it all the time. Likewise, sending full frame data to the decoders is slow(er), and iirc Dragly mentioned that larger res slowed down the UI updates, so we're a bit stuck there.

Anyway, I'll do some testing to see where the CPU eating/UI & decoder slowness tradeoff lies.

One option is to do a quick and dirty scaling by just taking every other pixel and sending this to the UI (and the decoders when low res data is sufficient), I'll have to do some testing.