[Live-devel] streaming multiple videos with multiple streams

[Warren Young]

On 6/5/2014 04:04, Ross Finlayson wrote:
>
> (In particular, if your network is WiFi, note that multicast generally
> performs very poorly over WiFi networks.)

Yes, wifi is a problem for all real-time systems.

First, the speeds claimed for wifi are basically marketing BS.  A "54 
Mbit/s" wireless network standard will give you 54 Mbit/s only when the 
two radios are sitting right next to each other inside an anechoic RF 
chamber sitting inside a Faraday cage.

Second, let's say you're really lucky and are getting 20 Mbit/s and your 
streams require "only" 10 Mbit/s.  Now along comes a burst of RF noise 
-- neighbor turned on the microwave or something -- and you get a short 
blip that knocks your average data rate down to 1 Mbit/s for a few 
hundred milliseconds.  That's a bullet to the heart of your 
communication stream.  You probably just destroyed an I or P frame the 
decoder requires in order to make sense of the B frames that did get 
through.

Even IP telephony over wifi can be an iffy thing.  Video requires much 
more bandwidth.