C
omrex
C
orporation
46
correction layer to use the same amount of bandwidth as the audio stream.
As an example, if your audio stream is consuming 80 kb/s of network
bandwidth, and UDP Max Retransmissions is set at 50%, up to 40kb/s
additional network bandwidth may be used for error correction.
Nagle Algorithm
– Nagle is applicable to TCP transmission only.
When Nagle is enabled, encoder packets are sometimes buffered and
concatenated into larger packets, depending on the network. It can be
used to lower overhead on TCP networks, but adding delay.
Advanced Decoder
options have to do with how the jitter buffer manager
performs. This is the algorithm that determines, based on network
performance, how much delay to install in front of the decoder to achieve
uninterrupted audio. It does this by creating a statistical analysis of the
amount of jitter experienced over a fixed interval of time (the window) and
making a judgment based on other parameters like the decoder’s resiliency
to errors. This is actually a very complex decision-making process involving
many variables, and most of the time the default parameters should work
well. The
Advanced Decoder
options are a means to override these
defaults, and changing them should be done with care.
The following advanced options affect the
Decoder
:
Retransmit Squelch
– These options are used to determine how the
buffer manager reacts to typical data dropouts like those seen on wireless
networks. Some explanation:
Many wireless networks have their own layer of data protection riding on
top of any other data layer, providing packet retransmissions in the event
of signal fade. The symptom from the network standpoint is that data will
come to a stop for some period of time while the signal is faded, and the
network will buffer all packets during this time. Once the wireless link is
restored, all the buffered packets will appear to the decoder as if they were
simply very late. In essence, the protection layer will “fight” the buffer
manager. The effect will be that the buffer manager will expand the buffer,
increasing delay dramatically without any benefit.
The
Retransmit Squelch
allows the decoder to detect these events and
avoid having the buffer manager react. The squelch has several user
adjustable parameters with good default settings. These should normally
be left where they are, but there may be unusual circumstances where they
should be changed.
A
dvAnced
d
ecoder
o
PtIonS
