Hi all!
I have bought a Pi Zero and a Pi 4 to try both for the ambilight.
The temperature is with both Pi at about 42°C when the ambilight is active.
The ambilight itself works. I didn't notice any obvious differences. I tested while I watched an episode with the familiy and I did a short test with a ambilight testvideo (fluid ...).
"Device" to "Frames per second" was on "automatic". "Size decimation" was on 4.
But that's strange: the effects are affected massive. With the Pi 4 the response time for changing from one to another effect is very smal. With the Pi Zero it needs 3 to 5 seconds to change the effect. Sometimes I had to click twice. And the effect itself does not work smootly. With the Pi 4 every effect is smooth and stepless. With the Pi Zero the effect "Plasma" on example does step slowly from one position to the next. The effect "Knight Rider" stutters from left to right end vice versa like a car on cobblestones.
The conclusion is:
Yes, you could use the Pi Zero but it sparkles with the Pi 4.