The answer, obviously enough, is that it can if it has Silverlight installed. Read on if you’re interested in how the web part will behave in its absence.
Last week we built a Windows Server 2008 R2 Hyper-V host that we used for our SharePoint 2010 launch event at Microsoft London. We were practicing the demonstration from connected Windows 7 laptops but we also wanted to understand the limitations of presenting from the host itself, should something go wrong with the networking. For the most part this worked fine, but we ran in to problems when we tried to run the media web part. The dialogue box would pop up as normal, but there was no option to Play. If I clicked View I would be prompted to download the .WMV file. At this point I realised that this hardened server did not have the Desktop Experience enabled, so it didn’t have a default media player.
After installing the Desktop Experience and rebooting (note: this does a few reboots), the pop-up looked the same; the Play button was still missing. Now if I clicked View it would launch in Windows Media Player.
Eventually it occurred to me that the server might be missing Silverlight. We install it by default, so it took some time for me to catch on. I checked the installed updates and sure enough, it was missing. When I tried to run Windows Update it revealed that Silverlight was the only availably update. I tried to install it and I quickly got error 80244019. Searching for a solution suggested a few possible answers – mostly network/DNS-related. To expedite things I visited the Silverlight site and installed it manually. I believe the problem may have been DNS or proxy-related but since all other Windows updates installed fine it’s a bit of a mystery.
Installing Silverlight manually did the trick. The Play option returned in the pop-up and video played normally. Out of curiosity I removed the Desktop Experience and tested again. Everything continued to work normally. All of this is totally clear in retrospect, but with the new technology cocktail that is SharePoint 2010, Silverlight 3, IE8 and Windows Server 2008 R2, it’s easy enough to loose sight of the obvious.