So let me put it this way:
I have a .mp4 H.264 video hosted on my own server. It's not using flash. It's not using QuickTime. It's a standard, H.264 video as you'd upload to YouTube or Vimeo or whatever.
What do I have to do to play this video file in-world? The official viewer won't play it. Firestorm won't play it. Singularity won't play it. I can play it just fine in VLC or QuickTime player, I can play it in my browser usingthe VLC plugin.
So did LL just adopt a video format *literally nobody* is using? Did they switch so every 'media' stream (even the parcel-based one) is just a web page? Do I have to get an HTML5 streaming player set up on my server to play my files? Because that would royally suck and be way too inconvenient to use.
Also, to anyone saying the hosting server determines playback, that's nonsense. It's a pile of data, nothing more. What opens it determines playback.