Clear-Com VOICE2 - Manual (Page 49)

Vitec Group Communications
VoICE IP Interface User Manual 3 - 9
Codec The choices of codec are:
1. 8kHz sampling rate
a. Speex
b. Speex ABR
c. Speex VBR
d. G.711
2. 16kHz sampling rate
a. Speex
a. Speex ABR
a. Speex VBR
a. G.722
b. Linear
3. 32 kHz Sampling rate
a. Speex
a. Speex ABR
a. Speex VBR
b. Linear
The G.711 and G.722 codecs are low latency
algorithms with only one available bitrate for
each which will function optimally in a con-
tained LAN with little or no packet loss. Speex
is more latent but provides a large variety of
bitrates for each of the sampling rate. Also,
Speex provides Average Bitrate (ABR) and
Variable Bitrate (VBR) which will optimize the
audio quality for a given bit rate. The linear
codec is simply a PCM pass through with no
encoding. It is the optimal audio quality but
uses a large amount of bandwidth.
Bitrate The theoretical output bitrate of the codec
chosen in kilobits per seconds. This does not
take into consideration the number of millisec-
onds per IP packets as well as the IP/UDP
overhead.
CONFIGURATION ITEMS
Item Description