Yep. I routinely use play the Buzz Out Loud HQ Video Podcast on my phone through the default photo viewer. What's interesting is if you click on the file through Astro File Browser it will say it's not supported...but if you just open the default player...it will show up and you can play it. I guarantee you that MKV's are supported...I think the phone can only handle a certain maximum resolution / bitrate. After all...even though its a 1 gig Snapdragon... it doesn't mean its even as good as a core-duo, core2duo or anything like that. It's its own entity. These are catching up to computers really really fast...but still aren't.