There is a live-action web series done by Microsoft and 343 Industries on the Youtube machinima channel starting October 5 leading up to Halo 4 release.
See this thread in the science fiction forum:
'Halo 4: Forward Unto Dawn' live-action web series
It is directed by Stewart Hendler
who has only done another scifi web series H+ The Digital Series
and some shorts.
Since no one has mentioned it I thought I would here.
Here is also a 5 minute behind-the-scenes video for the