Media acceleration of 1080p content is a non issue. Mobile phones on 2W can do that using only a couple 100 mW. There is absolutely no different in the capability of the slowest of Intel GPUs and the fastest Nvidia on a desktop. Video decoding happens on a special dedicated part on the chip and has zero to do with the general 3D video performance of the all purpose shaders and such.
All the Intel GPUs have media acceleration for 2 streams of 1080p. So you can watch two at the same time if you want. The GPU really doesn't matter for that purpose.