NewTek TriCaster TCXD300, User Manual

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Some sources report that the Flash movies will have a larger file size and use greater
bandwidth than Windows Media for a given stream quality. (This is hard to assess, and
changes constantly as developers update their products).
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Codecs for both types are updated with fair regularity, and when you choose the ‘latest,
greatest’ encoding, your viewers may not all have the current player, requiring them to
download and install updates.
BANDWIDTH CONSIDERATIONS
You’ll often hear the term ‘bitrate’ in connection with streaming video. This expression refers
data throughput per second (generally measured in Kilobits per second, or Kbps.) You could
think of this as being like water flowing through a hose. You control the ‘faucet’, because you get
to choose the
Stream Profile in TriCaster’s Stream Configuration panel. However, you don’t own
the ‘hose’ – or at least, not the entire hose. Once the stream leaves your immediate
environment, even if you can supply good throughput locally, bandwidth may be constricted
elsewhere along the transmission path.
The level of Internet traffic can impose limits, but another major factor is the sort of connection
your viewing audience may have.
Consider an example:
Even though you know that most of your audience is going to connect to your program using
(relatively slow) wireless devices, you use a very high outgoing bitrate – thinking that this will
surely be enough to fill the need. The fact is, though, a high bitrate actually ensures their
experience will be poor!
The client player tries to play the stream at the bitrate you specified, but (in this example) the
wireless bottleneck impedes flow. It is as if you connected a fire hose on your end, giving them a
suitable high capacity nozzle for their end – but in the last stage of flow, the stream must pass
through a small garden hose. Sadly, the stream will be quite insufficient, and output from the
‘nozzle’ (the client player) will falter badly.
For reliable performance, try to ensure the potential upload bandwidth from your system to the
net is around twice the bitrate you choose. You
can broadcast at a rate closer to your actual
ceiling, but reliable performance cherishes headroom.