Integrated graphics aren't part of any of the actual processors, but rather, the integrated GPU sits alongside the CPUs as one core sits alongside another, and

Integrated graphics aren't part of any of the actual processors, but rather, the integrated GPU sits alongside the CPUs as one core sits alongside another, and sharing the chip's L3 cache. CPUs communicate with the GPU via a memory-mapped interface, the same way they talk to most devices. The GPU itself does have its own architecture and instruction set, a lot of which are going to deal with specific coding schemes like H.265 rather than the generic sort of instructions you'd find on a CPU.