Don't get me wrong - this is still very impressive with a ~20w combined! power draw under full load, but it definitely doesn't beat mid - high desktop GPUs.
(This is largely irrelevant for video encoding/decoding though as you can see - as that's mostly done either on the CPU or dedicated silicon living in either the CPU or the GPU that's separate from the main graphics processing cores.)
[0] https://www.macrumors.com/2020/11/16/m1-beats-geforce-gtx-10...