[vetinari]

Video codecs usually come with GPUs, not CPUs. It is only on SoCs where this distinction is a more fuzzy.

On a GPU, you didn't have an option to interleave normal program stream with specialized partial-decoding instruction. You put encoded frame in and you get decoded frame back, the media engine was separate block from compute.

Though this is also changing; see Intel GuC firmware, which has (optionally) some decoding, encoding and processing based on compute.