Ullysses Eoff of Intel's Open-Source Technology Center has published the basic information how to get GStreamer-VAAPI running with Wayland. Right now you need to be using Git of libva (the VA-API library), the VA-API Intel driver, and then the 0.10 branches of GStreamer and its plug-ins. There's also a separate GStreamer-VAAPI Git repository off Gitorious that needs to be cloned as well. The current GStreamer work here is based upon the 0.10 branch and not master / the recently released GStreamer 1.0.
After building the components, while potentially needing to disable GLX support along the build process, the gst-launch GStreamer application can then play video files atop Wayland with the Weston reference compositor and accelerating the video playback on the Intel GPU via the Video Acceleration API. The build/setup process isn't too bad.
For more information see this mailing list post. For more reading, see Tear-Free, Hardware-Accelerated Video On Wayland. Aside from GStreamer, there's also MPlayer2 support for Wayland that has come about in the past few months.