EDD revenue increased primarily reflecting Skype and Windows Phone revenue, offset in part by lower Xbox 360 platform revenue. Xbox 360 platform revenue decreased $113 million, due mainly to decreased volumes of Kinect for Xbox 360 sold and lower video game revenue, offset in part by higher Xbox LIVE revenue. We shipped 13.0 million Xbox 360 consoles during fiscal year 2012, compared with 13.7 million Xbox 360 consoles during fiscal year 2011. Video game revenue decreased due to strong sales of Halo Reach in the prior year.
EDD operating income decreased reflecting higher operating expenses, offset in part by revenue growth. Cost of revenue grew $900 million or 16%, primarily due to changes in the mix of products and services sold and payments made to Nokia related to joint strategic initiatives. Research and development expenses increased $356 million or 30%, primarily reflecting higher headcount-related expenses. Sales and marketing expenses increased $244 million or 28%, primarily reflecting the inclusion of Skype expenses.