RoadRunner
U S E R S G U I D E
35
CCSO
and
CCSN
are both MUSICAM Layer II algorithms that are used
to communicate with older CCS Audio Products codecs built before
MPEG Layer II standardization.
ISO/MOEG Layer III
provides the widest bandwidth at low bit rates,
up to 15 kHz at bit rates of 56 or 64 kb/s. Layer III is often used at
these low bit rates when wide bandwidth is required; however, the
disadvantages of Layer III may outweigh this advantage. Layer III has
long delay, noticeable high frequency artifacts and does not cascade
well. In addition, post processing and equalization may adversely
affect the final audio quality. As with MUSICAM at lower bit rates,
lower sampling rates will provide better audio quality. At high bit
rates (112 and 128 kb/s) Layer III can provide transparent 20 kHz
monaural audio but still has the same disadvantages. Even at high bit
rates, Layer III has long delay, does not cascade as well as MUSICAM,
and is adversely affected by post-processing. In some applications,
Layer III may provide better-perceived audio than industry standard
Layer II, but in most applications, MUSICAM has been judged to be the
superior algorithm.
Quick Setup
The
RoadRunner
offers three ways of configuring the encoder and
decoder: Quick Setup, Advanced Setup and pre-programmed Quick
Configurations. Quick Setup is ideal when all encoder and decoder
parameters are the same. Quick Setup assumes that the decoder is not
independent of the encoder, and that the encoder and decoder bit rate
and line formats are the same. You can use this Quick Setup routine
when connecting to any MUSICAM USA or CCS Audio Products codec.
You must use the Advanced Setup sequence or Quick Configurations
when connecting to other manufacturer’s codecs, since the decoder
independent mode must be used.
Using the Quick Setup is easy. Select
<Operation><
algorithm
><Setup>
where
algorithm
= MPEGL2, MPEGL3, G.722, CCSO or CCSN
