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Why PowerPlay multipoint is so much better than using an MCU for multipoint
video conferencing:
Using an MCU ONLY provides QCIF Video Resolution
in a Continuous Presence Video conference - Multipoint conferencing
with an MCU/bridge works by having all the endpoints send their video
and audio to the bridge. The bridge then mixes all the video into one
composite CIF image, and sends that back out to the endpoints. Thus the
endpoint gets one video image of CIF size, that contains the rehashed,
reencoded images from all the other endpoints. The end result is a composited
stream of four participants at only QCIF resolution per video image.
PowerPlay multipoint provides CIF resolution video for each participant.
This results in a combined video resolution of 4 TIMES that of any competitor.
MCUs do not support multipoint calls at high bit
rates - Even leading manufacturers can only support up to 384kbps
in a 4-way conference.
PowerPlay supports 4 full CIF images in a 4-way
conference, with all 4 images running at up to 1Mbps providing superb
video quality.
Using an MCU increases Latency - It also
means all the video has to be decoded and re-encoded a second time at
the bridge, thus doubling the latency and reducing the video quality.
PowerPlay multipoint has extremely low 200ms latency.
Limited Resource - It also means that you
are at the mercy of the bridge's available resources when you want to
place a call. i.e. you must have an endpoint with a bridge for every multipoint
conference that you wish to have. Or you need a centralized MCU that supports
the total number of conference you wish to have at any given moment.
PowerPlay multipoint provides you with the ability
to place multipoint calls using as many PowerPlay endpoints as you have.
Very difficult to conduct Ad-hoc conferences -
With MCU-based conferences, the endpoints CANNOT ad-hoc invite new
people into the conference or hang them up. You can only do this by going
to the MCU itself, and controlling it, with it's own web-page interface
or application program.
Example: Placing an Ad-hoc call using an
MCU
I want to call Fred... I call Fred directly. Now, I decide I want
to invite in Jerry. Oops, now I have to hang up on Fred, and call
him back through the MCU. So, I call the MCU. Now, somebody has to
configure the MCU to let me call it. So now I've called the MCU, however
I still can't call Fred myself, I have to bring up the MCUs web interface
or application program (which I have to run on my endpoint) and ask
him to do it. By the way, if I'm using one of the industry leading
set-top products, I can't run the MCU program on it, so I need a PC
nearby to do that. Now I want to call Jerry. I go to the MCU control
panel again and tell the MCU to invite Jerry. If the MCU is busy,
or has too many endpoints using it right now, I'm out of luck. I can't
call Jerry.
Example: Placing an Ad-hoc call using PowerPlay
I call Fred. I call Jerry. That's the beauty of not using a bridge,
internal or otherwise. PowerPlay doesn't care what any other endpoints
are doing. PowerPlay doesn't have a bridge resource to worry about.
There can be 200 other multpoint conferences going on, and that makes
no difference to PowerPlay. When you you place a point-to-point call
to Fred, You use the same buttons, the same control panel, and the
same user interface that you use to make a 3-way call with Jerry.
PowerPlay doesn't treat 2-way calls any differently than 3 or 4-way
calls.
Transcoding with an MCU adds Latency and degrades
video quality - Transcoding means you have to decode video,
and then re-encode it before transmission in order to allow endpoints
to use different codecs. This increases delay and lowers video quality.
PowerPlay allows each video stream to have different
bit rates, frame rates, and codecs in the same conference without transcoding
the way MCUs do. PowerPlay directly creates the video streams using difference
codecs and transmits them. Each video stream is only ever encoded once
for maximum quality, minimum delay. If you are in a multipoint conference
with three participants on a high speed LAN and one on a lower speed connection,
the one person on the low speed connection can recieve lower quality while
the others can still have high quality.
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 IPContact
Software
PowerPlay
CS901-PROX
PowerPlay
RollAbout Carts
NTSC
Gateway
| "I do think, however, that the unit sells
itself. It is sooooooooooooo user friendly. My favorite part of the
workday is working with the PowerPlay unit! "
Jackie Cowan
Frostwood Elementary
Springbranch Independent
School District
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