Telos Zephyr iPort - Manual (Page 16)

10 | section 2
Codec configuration
Global Options
Confirm that the factory default is set for 8 encoder / decoder channels. (The 16-channel
encode-only option is used for streaming applications.)
Codec and Channel Settings
Usually, the first step will be to click the Options button for the channel you are configur-
ing to set the details of the codec and protocol parameters. Having done so, you will see this
this page:
Encoder
Set the codec type, bitrate, and stereo/mono mode you want to use for this channel.
The Protocol type is either UDP or TCP. There are tradeoffs in this choice that are only
fully understood if you have knowledge of this aspect of IP networks. Here is a simple
overview: UDP is the usual choice because it offers lower delay than TCP and is not
impaired by TCP’s flow/rate control. However, with UDP, there is no network recovery of
lost packets as there is with TCP, so the codec’s concealment is used to reduce the audibility
of these events.
With AAC, up to around 10% random packet loss can be effectively concealed. This is
one of the strengths of AAC. The other codecs also have concealment, but it will not be as
effective.
Network links with high and guaranteed Quality of Service will almost always let you use
UDP without trouble.
The Enable SHOUTcast protocol option is used only for streaming with an external
server, so is not checked.