How to build a Video Broadcaster, which can handle more than 20,000 viewers

Question

I want to broadcast Video from a web cam, over internet. The problem is, the Video will be viewed live by more than 20,000 people (expected).
I have a very little experience with Red5 Broadcasting. I did some broadcasting using Red5 and Flash. It works fine for 1 or 2 viewers i.e. it is great for personal chatting/ video conferencing applications.

But, when the number of viewers increases, the delay in Broadcasting also increases. I am experiencing a Delay addition of about 0.5 Seconds for every new user who joins the broadcast.

Can any one suggest me some, better technologies on which I can work out this Live Broadcasting. I don't want to use http://www.ustream.com; I want to create one of my own, such tool. But thats always the last solution.

Answer 1

20000 concurrent video views is going to stretch the most powerful of servers. I'd consider looking at Flash Media Server, but I doubt that serving this amount of video from a single box will be viable. Assuming a minimal bitrate of 256k (it won't look all that good at this rate), we'd be talking about an upstream delivery of around 5 gigabit /s. That's some seriously heavy lifing. If it exists, I doubt it will be free.

Answer 2

As you're expecting such a large number of viewers, P2P distribution could be a way to go. This way, under heavy numbers the load will be moved away from your servers, and on to the clients. They would act as 'repeaters' for your content. This may of course introduce even more delays.

Check out PeerCast and Freecast for more info.

Answer 3

I can tell only about erlyvideo, it can handle 2000 clients, streaming 500kbits to each.