>>105641478vp8/vp9 and even av1 are all easier to decode than the mpeg counterparts when it comes to software decoding
the problem is that the mpeg formats (except with the new h266) are hardware accellerated much more commonly, so it's tough to determine.
a gpu that has hardware decoding for both av1 and h264 will have basically no difference in cpu required or power use (actually, on amd rdna 3 gpus h264 is slightly more power hungry than all other codecs for example), but since that's not always the case while h264 has hw decoding everywhere, the question is really hard to answer.
>What's the closest alternative in open source format?vp8, which overall sucks ass and barely competes with it, plus the h264 patents are expiring soon which will make vp8 completely irrelevant and pointless to use in any case.
only valid use case for vp8 when ignoring patents was to allow youtube to work on the nintnedo wii, it didn't have h264 hardware decoding and h264 quite heavy to do it in software on such dogshit hardware.