Tieline Commander G3 TLR300, Reference Manual

Page: 221 / 383

Section 24: Connection Setup
T ieline
T E C H N O L O G Y
Page 221
One of the unique features of the
T
ieline
Music
algorithm is its ability to send
a 15 kHz stereo audio signal over a single B-channel, with a delay of only 70
ms… pretty impressive huh!
This brings us another point – delay. This is an important issue to consider if
you are broadcasting live. An MPEG-2 Layer 2 (
MP2
) algorithm would not
only require 128 kbps of connection bandwidth, but it would also have a
delay of over 150 milliseconds. This would most likely be above the
comfortable threshold of delay for your broadcast.
When dealing with variable bit rate connections, such as over POTS, IP and
3G connections, it is a good idea to listen to the quality of your program
signal and to see how it sounds when it is sent at different bit-rates. For IP
and 3G/IP connections this may also include assessing your connection
stability at different rates of FEC (Forward Error Correction).
If you have limited or varying bandwidth you may be better off using an
efficient high-bandwidth algorithm like
T
ieline
Music
, rather than
MusicPlus
or a more bit-hungry and higher-delay MPEG algorithm.
Remember that audio quality to a certain extent is subjective. Ultimately, by
testing connection stability at different bit rates (and FEC settings), you will
learn how to optimize your settings depending on your connection situation.
Please see the section titled Connection Bit-rate and Algorithm Options in
this reference manual for more detailed information on bit-rates of
connections based on algorithms selected and connection types.
24.10. Tieline Algorithms Available
The algorithm settings in
T
ieline codecs vary according to
the
Connection type
selected.
T
ieline now offers two
optimized low-delay
Music
algorithms which are ideal for IP
and wireless IP connections.
The algorithms available include the following:
Music
,
MusicPlus, G.711
,
G.722, MP2 Mono, MP2 Stereo, MP2
J-Stereo
,
Voice G3
and
MP2 Dual
(
Transcriptor Tx
and
Transcriptor Rx
are used in captioning enabled codecs
only).
Following is a description of each of the algorithms in your
codec and following this is a handy reference guide in a
tabular format, for deciding which algorithm is best to use in which broadcast
situation – depending on your connection type and the connection bit rate that is
possible.