Definitions for Video
Telepresence Systems
The Video Telepresence module provide in depth coverage of
the high end video telepresence systems offered on the market, from
Personal/Executive systems to large Group systems.
While the high end video telepresence systems share
a number of common traits, there are also several differentiating factors that
need to be considered before making a purchase. Some of the common capabilities
of these systems are that they offer life-size (or near life-size) image displays,
very high quality audio and full motion video, minimal camera to eye angles (to
provide virtual eye-to-eye contact between meeting participants), and high
prices. Telepresence vendors have also gone to great length to ensure that
these products provide the user with a truly lifelike meeting experience. It’s
the differentiating factors, however, that will most effect the users
purchasing decision, and these include flexible or customized room offerings,
bandwidth requirements, availability of fully managed service offerings, size
and quantity of displays, and overall quality of the telepresence conference
experience (potential users are encouraged to participate in a demo conference
before making a final purchasing decision).
T3i Group’s comparative database module provides detailed
information on each vendor’s individual product offerings so all products can
be viewed and compared on an equal footing. The Video Telepresence module
includes approximately 45 fields of information, each of which is defined as
follows:
Company
Name: Provides the name of the videoconferencing product vendor
U.S.
Headquarters Location: Lists the city and state where the vendor’s U.S.
headquarters are located
Main
Telephone Number: The primary telephone number at the vendor’s U.S.
headquarters location
Internet
Address: The vendor’s web site address
Product: The model
name for each of the vendors’ products being covered
Product
Introduction Date: The date that the vendor first introduced or first
started shipping the product
Type of
Equipment: Describes the particular type of equipment being offered,
such as Personal/Executive, Small Group, Group, Large Group
Date
Information Verified: The actual date when the product information was last
checked and verified to be correct and current
Customized
Room or Flexible Design: Some telepresence systems are offered as complete
turnkey installations that include all of the equipment, lighting, acoustics,
walls and furnishings where all rooms look alike and provide the same meeting environment
regardless of location; some vendors and users prefer this approach as they
feel it adds to the immersive experience because it creates the feeling that
all participants are in the same room with the same furnishings, etc. and that
it therefore provides for a more lifelike experience; for these type of
installations, some vendors require that space be provided and that they
construct the entire room while other vendors can utilize an existing room and
convert it into a telepresence room; the other alternative is to offer a
flexible design where the telepresence equipment is outfitted into existing (or
specially converted) rooms but where the user has the option of using either
the same or different furnishings at different locations (since some users
would prefer that different geographic locations have a different look);
telepresence vendors may also offer either a complete package of equipment
including all codecs, cameras, displays, microphones, audio speakers, lighting,
acoustic treatments, etc. or they may allow the user some flexibility in
selecting certain components (such as displays)
Number of
Conference Participants (per site): This field identifies the number
of meeting participants that can typically be accommodated at each video telepresence
meeting site using the particular product; in some cases the range of
participants or maximum number of participants is precisely limited by the fact
that the product is using a customized room that has been provisioned with a
table/desk and certain number of chairs (along with the required microphones,
cameras, displays, etc.
Bandwidth
Requirements: May state the bandwidth (or bandwidth range) supported (or
required) by the product for either or both IP/ISDN connectivity, or could
state the minimal or optimal bandwidth requirements for that product
Audio
Standards Supported: Lists the audio standards (as defined by the
International Telecommunications Union (ITU)) supported by each product, along
with the audio range.
G.711-a
56/64Kbps bit stream for 3.4KHz audio
G.722-a
48/56/64Kbps bit stream for 7KHz audio
G.722.1-a
24/32Kbps bit stream for 7KHz audio
G.722.1
Annex C-the ITU’s adoption of Polycom’s Siren 14-14KHz audio
G.723.1-a
5.3/6.4Kbps bit stream for 3.4KHz audio
G.728-a
16Kbps bit stream for 3.4KHz audio
G.729-an
8Kbps bit stream for 3.4KHz audio
AAC-LD-MPEG2 Advanced Audio
Coding-Low Delay format for 7KHz or 14Khz audio; also MPRG4 AAC-LD for 20KHz
audio (CD quality)
Audio range is stated as 3.4KHz,
7KHz, 14KHz, 16KHz, 20KHz, etc.
The user should keep in mind that typical human hearing
range is from 20Hz to 20KHz; therefore a videoconferencing system supporting
audio capability below 20Khz will provide something less than the full
available range that the human ear can detect. Also keep in mind that typical
telephone quality audio is at 3.4KHz, while CD quality audio is at 20Khz. Also,
when using a high end telepresence system it should be essential to provide the
best available audio capabilities to ensure a truly life-like meeting
experience.
Full
Duplex Audio: Full duplex audio means that the videoconferencing system
allows conference participants at multiple locations to speak at the same time
and be heard at all locations. In systems that do not support full duplex
audio, a person speaking at one location may override and cut off those
speaking at other locations (as the audio can only flow in one direction at a
time).
Video
Standards: To begin, there are three high level, umbrella standards
issued by the ITU for videoconferencing. These are the H.320, H.323 and H.324
standards, and they are broadly defined as follows:
H.320 – the public switched
telephone network (PSTN) standard for video over ISDN (BRI or PRI), and also
applies to dedicated network connections such as T1 and satellite based
services
H.323 – the
standard for video over a LAN or IP network
H.324 – the standard for
transmission over Plain Old Telephone Services (POTS), or audio telephony
networks
Under these umbrella standards are several individual
standards, each of which addresses various issues related to communications and
video transmission, and includes the following:
H.221 – Under the H.320 umbrella,
defines the transmission frame structure for teleservices from 56/64Kbps to 2
Mbps
H.223 – Multiplexing protocol for
low bit rate multimedia connections, such as transfer of a combination of
digital voice/audio, digital video/image, and data information over a single
communications link
H.224 – Real time control protocol
for simplex (one-way) use of a data channel using H.221 (for applications like
far end camera control)
H.225 – Multiplexing transmission
formats for media stream packetization and synchronization on a non-guaranteed
QoS LAN
H.230 –
Under H.320, for controlling synchronization of video frames
H.231 – Multipoint Control Unit
(MCU) to bridge 3 or more conferencing systems at rates to 2Mbps
H.239 – Endpoints that support
H.239 can receive and transmit multiple, separate media streams, usually for
voice, video and data collaboration
H.241 – Defines extended video
procedures and control signals for multimedia terminals
H.242 – Under H.320, defines
protocols for dall set up disconnect at rates up to 2Mbps
H.243 – Under H.320, defines
control procedures and protocols for MCU call set up at rates up to 2Mbps
H.244 – Deals with H.221 bonding,
or the aggregation of multiple 56/64Kbps channels
H.245 –
Under H.323, relates to control of multimedia communications
H.261 – Video codec for
audiovisual services at px64Kbps (supporting QCIF/CIF resolutions); defines how
the picture information is compressed and coded for transmission over low
bandwidth networks
H.261 Annex D – Protocol for
transferring high quality still images at 4CIF resolution
H.263 – Video coding for low bit
rate communications, designed for lower transmission rates (at 64Kbps to
128Kbps)
H.263+/++ - Represent two higher
levels of the H.263 standard that include improved encoding efficiency and
improvements against data loss during transmission
H.264 – A video codec standard
that greatly improved image quality at significantly reduced bandwidths; this
standard effectively made it possible to transmit the same quality video at
half the bandwidth (as compared to systems that did not support the H.264
standard)
H.281 – Far
end camera control protocol for videoconferences using H.224
H.331 – For
broadcast mode videoconferencing
H.350 – Relates to storing and
retrieving information from enterprise directories (also referred to as
LDAP-Lightweight Directory Access Protocol); on systems supporting this
protocol it is possible to link to existing corporate contact directories to
set up videoconference calls, making it easier for the users
It should be noted that the comparative database modules
list all of the standards that appear in the available literature for each
vendor’s product (or for which the vendor has notified T3i Group of their
support for that standard). There may, however, be some products listed that
support more standards than are actually shown in the database (since some
vendors do not see the point of listing each and every standard supported on
their product, but instead mention only those standards that are of major
significance).
Data
Standards: In addition to the H.239 standard (previously included under
Video Standards), which allows for separate data streams to support data
collaboration, there are a couple of significant data standards that are
covered under this heading, which are:
T.120 – A family of standards that
define the protocols for data collaboration (such as file transfer, still image
transfer, shared whiteboarding, etc.)
T.140 – Protocol for multimedia
application text conversion (online chat) over an IP network, used by both
H.323 and SIP systems
Additionally there are various encryption standards that are
covered in the next attribute field of the database.
Video
Resolution: Video resolution is a measure of image quality and clarity.
The higher the resolution, the better the quality and clarity. Video resolution
is measured as the number of pixels across times the number of pixels high
(where pixels are individual colored dots that are used to form the images
presented on screen). While higher numbers (and therefore higher resolutions)
mean better pictures, they also mean more memory/bandwidth to store and transmit
the information. In some cases there may also be tradeoffs in maximum frame
rate (the speed at which the video images are refreshed expressed as frames per
second or fps) and the maximum resolution. As an example, standard definition
(SD) analog TV offers 480i resolution (at 720x480 pixels) running at 30fps;
extended definition (ED) TV offers480p resolution (at 720x480 pixels) also
running at 30fps; high definition TV offers 720p resolution (at 1280x720
pixels) and ultrahigh definition (HD) TV offers 1080p resolution (at 1280x1080,
1440x1080, or 1920x1080 pixels). The list of video resolutions offered and
supported on the different systems consists of the following (which includes
resolution levels applicable to still image/graphic files):
QSIF – 180x120
SIF –
352x240
4SIF –
704x480
QCIF –
176x144
CIF (or
FCIF) – 352x288 (about the same as VHS quality video)
4CIF –
704x576 (close to broadcast or DVD quality video)
QVGA –
320x240
Half VGA –
640x240
W288p –
512x288
400p – 528x400
W448p –
576x448
VGA –
640x480
W576p –
1024x576
SXGA –
1280x1024
XGA –
1024x768 (typical PC/laptop display)
480i/p –
720x480
720p –
1280x720 (high definition)
1080p –
1920x1080, 1280x1080, or 1440x1080 (ultra high definition)
Video
Frame Rates: Defines the speed at which the video image is displayed, so
30frames per second (30fps) means that 30 separate frames are changed every
second. As a basis to understand this term, standard definition TV typically
runs at 30fps while high definition TV typically runs at 50/60 fields per
second. The higher the frame rate the smoother the video image. Lower frame
rates could result in less fluent video movement and very low frame rates could
result in a rather choppy appearing video. Typical frame rate offerings include
15fps, 30fps, and 50/60 fields per second.
Inputs: Provides
information on the audio, video and ancillary inputs supported by the
videoconferencing system. Typical inputs would be provided for cameras,
microphones, document/auxiliary cameras, a PC or other data device, a VCR/DVD,
or other device; note that some video telepresence systems are sold as
complete, fully packaged units consisting of the video codec, camera, display,
microphone and speakers and so may not have any additional inputs
Outputs: Provides
information on the audio, video and ancillary outputs supported by the
videoconferencing system. Typical outputs would be provided for
monitors/displays, audio speakers, a VDR/DVD, or other device; note that some
video telepresence systems are sold as complete, fully packaged units
consisting of the video codec, camera, display, microphone and speakers and so
may not have any additional outputs
Network
Interfaces: This section identifies the basic type of network
connections or interface options supported by the video systems, generally
listed as IP (which can be IP, LAN, DSL or cable modem), ISDN (which could be
BRI or PRI, or both), and V.35 (for a private line network)
Display/Monitor
Type: Lists the type(s) of monitor/display unit(s) supported by
the video telepresecne system; typical systems utilize external displays (which
again could be a standard TV monitor or a particular display with a required
resolution rating); also note that some vendors include the display/monitor(s)
as part of the system package, while others may allow the user to select their
own compatible display/monitor(s) (or reuse existing equipment); and kep in
mind that larger displays are typically needed for telepresence systems to
ensure that images appear as truly lifesize
Number of
Displays: States how many displays/monitors can be connected on the
system; all systems require at least one display, some support a second display
(for data presentations or other uses), and some systems support multiple
displays to allow for more conference participants to be viewed from one or
multiple locations
High
Definition: Identifies whether or not a videoconferencing system can be
operated in true high definition (HD) mode, running at 720p or 1080p
resolution; these systems require HD codecs, HD cameras and HD displays (with
some also offering specialized HD audio components)
Camera
Type: several types of cameras can be used on videoconferencing
systems, although not all types are supported on all systems; also keep in mind
that some video systems come as integrated or packaged units with the camera
(or cameras) included, while others allow (or sometimes require) the user to
acquire a camera of their own choosing (so long as it is supported by the video
system being used); some of the more common types of cameras available include
the following:
Fixed Focus Camera – cameras with
a fixed viewing angle and focal length; may have a manual focus adjustment
Pan, Tile, Zoom (PTZ) Camera –
cameras that can pan, tilt and zoom, typically with some remote control capability
so the user can maneuver the camera angle and focus, or utilize defined preset
positions to automatically move the camera to a particular object or point in a
room
Voice Tracking Camera – this is
typically a more advanced version of a PTZ camera that actually changes it
sfocus based on who is currently speaking in the room
HD (High Definition) Version
Cameras – there are also HD versions of Fixed Focus, PTZ and Voice Tracking PTZ
cameras available, which are also required to support a truly HD videoconferencing
system
Many videoconferencing systems also support the use of
optional document cameras which can be used to transmit still images during a
video conference, for example as part of a presentation (to show a product or
some document).
Number of
Cameras: Indicates the number of cameras supported by the
videoconferencing system (which could also be shown as the number of main
cameras and document or auxiliary cameras)
Camera
Controls: Typical camera controls would be manual focus, pan/tilt/zoom,
and presets (near and far end) that allow the users to preselect particular
camera settings to view sections of a room or objects in a room based on the
established presets
Camera
Positioning: This is a very important point of consideration for video
telepresence systems as proper camera to eye angles are critical to providing a
lifelike meeting experience where users can look each other in the eye during
the meeting (and not appear to be looking away from the other participants);
some vendors position the cameras directly above the display, others position
the cameras in between displays and others position the cameras behind the
displays centered or at actual eye level; subtle differences make themselves
aware if the user actually tries out the equipment in a demo environment
Data/File
Sharing: Indicates whether or not the videoconferencing system
supports the sharing of data files or presentations (such as spreadsheets or
other documents) on screen during the video conference; this application would
generally require a PC or other device to be integrated into or connected to
the videoconferencing system
Integrated
Desktop Facilities: Some telepresence systems, expecially those offered
as completely equipped rooms, come with integrated desktop facilities such as
built in popup displays for file sharing and presentations; other systems allow
the meeting participants to connect a PC for that purpose (or to connect
multiple PCs for use by different participants)
Multipoint:
Videoconferencing systems operate in either point-to-point mode (with
two sites directly connected to each other) or multipoint mode (allowing
multiple sites to participate in the same conference call). Multipoint
conferences can be accommodated in two basic ways – in some cases all sites are
interconnected to all other sites; the alternative is that all sites are
interconnected via a Multipoint Control Unit (MCU). Additionally, MCU
functionality can either be embedded into the videoconferencing system codec or
provisioned via an external MCU product offering.
Interoperability:
States whether or not the video telepresence system being offered can
interoperate with videoconferencing systems from other vendors, including
traditional standards-based videoconferencing systems, as well as systems that
may use either IP or ISDN network conenctivity
SIP: States
whether or not the videoconferencing system supports the Session Initiation
Protocol (SIP), which is used to provide presence indication, among other
things, so that the videoconference setup can be more tightly integrated into
things such as Instant Messaging, as well as support integration with other
applications. Pure IP-based products may support the SIP signaling protocol for
Internet conferencing, telephony, presence management, events notification, and
instant messaging. SIP is used for call setup and teardown, routing requests
between locations, and to initiate information transfers, as well as to enable
translation of text names, email addresses, and phone numbers into IP addresses.
Picture in
Picture (PIP): States whether or not the videoconferencing system
supports the Picture-in-Picture feature that allows two (or more) images to be
shown on a single display at the same time, one (or more) of which is usually
shown as a small (inset) window; some systems also support Picture and Picture
which typically shows two images side by side using a split screen
Split
Screen: This capability is typically used on single monitor systems
so that the far end participant and a data presentation (for example) could
both be seen at the same time, or so participants from two remote sites could
be displayed on the monitor at the same time
Multilingual:
Defines whether or not the system supports multilingual services, such
as for the user interface and call setup screens (which could be on the users
monitor or accessed via an online web portal); this is not to be confused with
multilingual services that would provide language translation among multiple
participants or other such services
Record and
Playback: States whether or not the videoconferencing system supports
a video recording capability which would allow users to record the
videoconference session, store (or archive) it, and then access it at a later
time for playback
User
Interface: Provides information on the type of user interface offered
on the system for call setup and control; typical user interface offerings
include remote control units, a computer mouse used with an onscreen menu, a
touch control pad, a web portal, etc.
Lighting/Acoustics:
States whether the vendor provides the necessary lighting and acoustic
treatments needed for the video telepresence room; if there are special
requirements for the user to provide certain lighting and acoustic treatments;
or if existing office/room lighting/acoustics can be used for the facilities;
users should keep in mind, however, that proper lighting and acoustics are
critical for these high end video telepresence meetings to ensure the highest
possible quality of audio and video
Room Size:
For customized room environments, this field will provide information
relative to the amount of space needed to accommodate the video telepresence
facilities; for flexible room environments the vendors may state a minimal room
size requirement or recommendation
Network
Services Offered or Required: Some video telepresence vendors
offer both equipment and a network services package specifically designed for
these video conferences and these network service offerings may be required or
offered as an option for the user; other vendors may allow the user to utilize
their own, existing network facilities or select their own service provider;
the same may be true of various distribution channel partners that may offer
the video telepresence systems with or without a network service to go along
with the package; in any event, whether offered or required, the network
service offerings are usually at a monthly rate separate from the cost of the
equipment itself
Managed
Service Offered: Here again, a Managed Service may be offered or
required as part of the total video telepresence package; the Managed Service
could include the Network Service offering as well or cover just the video
telepresence rooms, meeting setup and monitoring, etc.; a complete package
might also include full maintenance of the video telepresence equipment, always
on service, concierge meeting services (for setup and monitoring), technical
support and operator services, continuing updates and enhancements, etc.
QoS, SLA
Offerings: Typically a fully managed service with network services
included will also provide the user with various QoS and SLA offerings to
ensure the highest possible quality and level of service for the duration of
the contract
Additional
Capabilities: This field is used to list any additional capabilities or
optional accessories that may be offered on the particular videoconferencing
system (that have not been addressed in any of the previous data fields)
Pricing: States the
basic list price (in US$) for the videoconferencing system and its primary
components and options; where available, typical discounts and/or street prices
are also shown
Strengths:
List the strengths of the videoconferencing system and/or the vendor as
compared to other like products available in the market
Weaknesses:
List the weaknesses of the
videoconferencing system and/or the vendor as compared to other like products
available in the market