It's interesting that they're going to allow people to spectate from the game client. I assume they won't have anyone casting for people spectating via the game client, but will have a regular casted stream on twitch.tv?
It will be interesting to see how the client handles several thousand? tens of thousands? hundreds of thousands? viewers watching the same game. I know League of Legends tournaments regularly get over 200k watching the casted streams, so I'm very interested in what will happen during the Dota 2 International.
I think you'll be able to listen to casters in game too. There's the capability to send audio streams with the game data too. Similarly camera control can be shown by the casters.
Dota2 implements what HLTV and SourceTV have been able to do, seamlessly.
Basically the way it works is this. Game is hosted on a server, TV Client/casters connect to that. That master server then can stream out to hundreds of repeating servers. Spectators can connect to those repeating servers. In theory it should work flawlessly and have no impact on the players playing. I wonder if they've deployed a bunch of servers that can automatically allocate more resources to stream popular games. That'd be pretty nifty
Amazing tournament, valve just seems to do everything right. Streaming/commentary worked so well and hollywood final of best of asia vs best of europe. Hopefully valve strikes up a deal for dota 2 in china and it could really take off now they have the pros involved.