Polycom VSX 7000
Product Reference Guide
October, 2003
H.264
H.264 is the 3
rd
generation of video algorithm standard being ratified by the ITU-T standards organization. This is
advancement from the previous H.261 and H.263 video algorithms. The standard is applicable for H.320 and
H.323 calls.
The main benefit of this new standard is that it provides very sharp video images even at low bandwidth calls.
H.264 is especially effective at rates up to 384 kbps. At higher bandwidths (512 kbps and higher) H.263 with
interlaced video (Pro-Motion) will continue to provide higher, more natural motion with great resolution.
On all Polycom systems, the appropriate video algorithm is chosen automatically. User does not have to manually
set this before a call. In a multipoint call with MGC v5.0, the profile of the conference will define what video
algorithm is used.
Pro-Motion
Pro-Motion is a trademark name for Polycom’s implementation of interlaced video under the H.263++ video
standard. With interlaced video (a.k.a. 60 fields per second), both odd and even fields of a 30 frames per second
(in NTSC, 25 in PAL) of a live camera image are transmitted and rendered at the far end. This results in an
image with higher spatial resolution and better motion rendition, which is optimal for “people” views. The
alternative traditional 30 fps view produces some effects users typically perceive as “unnatural” video.
Pro-Motion on VSX systems can be activated as low as 512 kbps and produces a full screen image, rendering on
the far-end the entire image captured by the camera.
4.3. Audio Compression
VSX 7000 supports a large set of audio compression algorithms in the industry. In addition to a full complement
of ITU-T standards algorithms, VSX 7000 supports Siren™ 14, a new algorithm with a frequency response of 14
kHz.
The following table lists all algorithms supported:
Algorithm
Frequency response
Bandwidth
Supported in
Siren 14
14 kHz
24 – 48 kbps
H.320 and H.323
G.722.1
7 kHz
16 – 32 kbps
H.320 and H.323
G.722
7 kHz
48 – 56 kbps
H.320 and H.323
G.728
3.4 kHz
16 kbps
H.320 and H.323
G.711
3.4 kHz
56 kbps
H.320 and H.323
Siren 14 is the latest audio compression algorithm, delivering 14 kHz of audio response at bit rates of between 24
and 48 kbps. Polycom is the only company in the industry to offer such “super-wideband” audio capabilities,
which provides incredible audio quality approaching that of CDs and MP3, while maintaining a modest network
bandwidth requirement. With 14 kHz audio in a videoconference call, participants can better hear and
understand each other, while eliminating the fatigue often associated with longer duration calls under inadequate
audio quality.
Siren 14 is supported on Polycom’s VSX 7000 and iPower videoconferencing endpoints, as well as MGC
multipoint servers.
Polycom Confidential
Subject to change without notice
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