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A
C
BOUT
ODECS
A
A
BOUT
UDIO
T
RANSCODING
A number of video conferencing terminal applications require the G.722 and
G.722.1 audio compression codecs to provide high quality voice
communications. The G.722 and G.722.1 formats, using a digital sampling rate of
7 KHz, provide higher quality voice sampling with a greater dynamic range. The
Gateway does not transcode G.722 or G.722.1, but supports them transparently.
Since the G.722 codec is of a much higher audio quality than other codecs and
requires higher bandwidths, the Gateway supports G.722 and G.722.1 at the
following call bit rates:
G.722 is supported in calls at 224, 256, 336, 384, 448, 512 Kbps (all
Gateways) and 768, 1472 and 1920 Kbps.
G.722.1 is supported in calls at 64, 2B, and 128 Kbps.
Both endpoints in a call must support G.722 and G.722.1 audio codecs.
The Gateway P20 SP supports audio transcoding through the Audio Transcoder
Module (TCM). Other
on-board Digital Signal Processing (DSP).
The TCM is a PCI mezzanine card (PMC) that implements Digital Signal
Processing (DSP). The TCM has a processing capacity of up to 20 channels for
audio transcoding in video calls.
The Gateway TCM can perform audio transcoding between the following types
of audio protocols:
G.711 (ISDN) to G.723.1 (IP)
G.723.1 (IP) to G.711 (ISDN)
G.728 (ISDN) to G.711 (IP)
G.711 (IP) to G.728 (ISDN)
When your unit includes both the
Note
MCU, G.728 transcoding is supported on the MCU only.
RADVISION
Each audio codec differs in the audio quality, compression, and bit rates that it
provides. The G.711 codec provides toll quality audio at 64 Kbps, the G.728
codec provides near toll quality audio at 16 Kbps, and the G.723.1 codec provides
voice quality audio at 5.3 or 6.4 Kbps.
Gateways support audio transcoding through
RADVISION
RADVISION
Configuring the SCOPIA Gateway
Configuring Gateway Settings
Gateway and the
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