Bandwidth usage partly depends upon the number of meeting participants, unless IP multicasting is enabled on your network. Multicasting allows you to send data once, and it is then replicated further down the network. You can set the screen bit-color, though the default 24-bit colour depth allows high quality imaging and transfer over relatively low bandwidth networks.
It’s important to notice the difference between latency and bandwidth here – bandwidth determines the amount of data that can be setn at once, latency the time it takes to get there.