Just to add on the above question.
You could use iptables with user matching to color the packets like so:
iptables -t mangle -A OUTPUT -p tcp -m owner --uid-owner someuser -j MARK --set-mark 100
And then use 'tc' to limit on a per user basis.
Technically, given the units in your question your math is wrong. However, it is more semantically wrong as it could be construed as right depending on how one defines the units.
The big confusion comes down to the unit being used. A kilobit versus a kibibit. A megabit versus a mebibit.
See the Wikipedia page on Data rate units for more detail.
Additionally, I am going to assume on the wire data rates for the stream. If your media stream -- what the encoder is outputting, is 1,024 kilobits per second the on the wire data rate (RTP, UDP, IP, Ethernet overhead) will be larger than 1,024 kilobits per second. You must take into account overhead if you want to be exact in the real world. However, the example below is to illustrate the math regardless of encoder output rate.
For our example, I assume the on the wire data rate is 1,024 kilobits per second, meaning encoder output is less than 1,024 kilobits per second.
A 1,024 kilobit per second on the wire data rate is 1,024,000 bits per second. A 100 megabit per second link is 100,000,000 bits per second.
100,000,000 bps / 1,024,000 bps yields 97 possible "streams/data rates" of 1,024 kilobits per second on a 100 megabit link.
Like my physics teacher always stammered: Units! Units! Units!
Best Answer
Arbitrarily.. Usually. Unless your AP is doing some intelligent per-user limiting, it's pretty much just shared equally.
This depends greatly on which access points you're using. If it's a Linksys or Netgear thing for consumer use, you're often lucky to get 5-10 consecutive connected clients.
On the other hand, if it's a high-end enterprise wireless AP, you could be looking at 50-100 connected clients.
Xirrus APs can support between 250 and 1920 connected clients with the really large radio arrays, depending on the specific device.
That's called Quality of Service, and you'd need to configure it on the Access Point (and on the router and other network devices). You'd typically configure rules to rate-limit traffic to certain ports or destination IP addresses. The complete answer for this is out of scope for this question, and is more then adequately explained by various articles on the topic, as well as the documentation for your specific Access Point and router hardware.
Certain Wireless AP solutions provide a management interface which has pre-defined classes of traffic, such as "Youtube" and "Vimeo" and also classes such as "Social Media" and "Video Sites" which you can use to rate-limit all traffic to these sites.