Nefsis supports virtually any
off-the-shelf webcam, including the latest 720p-capable devices,
and HD pan-tilt-zoom conference room equipment. We get a
lot of questions about high-end hardware versus the actual video
quality as seen in the real world. In particular, there are web
conferencing services that claim HD, but their users experience
performance in the range of only 4-6 frames per second, and far below HD
Nefsis multi-core software has no limits. It will support
the resolution and frame rate of your camera and the effective bandwidth
available on a user-by-user basis, delivering true HD video conferencing.
Competing products and online services often fail at one or more of the
key steps below.
When is HD not HD?
High-definition (HD) in video conferencing used to require
dedicated boardroom-to-boardroom network connections and
standalone encoding/decoding hardware such as those manufactured
by Polycom, Tandberg and LifeSize.
As personal computers have increased in processing power, HD in
desktop-to-desktop video conferencing is a reality, using
ordinary hardware and an Internet or local network connection.
But not all desktop video conferencing products claiming HD
are created equal, and this confuses buyers. If HD-quality is
important in your organization's online meetings, you need to
understand what you must (and must not) put in place in order to
deliver it. Otherwise, you'll need to answer your conference
participants when they ask, "Why is the image so grainy?"
What is HD?
Current HD standards are:
- 720 progressive scan lines at 60 frames per second and 16:9 aspect ratio, or
- 1080 interlaced encoding at 50 fields (25 frames) per second and 16:9 aspect ratio.
HD video does not break down or appear pixilated when
magnified on the destination display. True HD preserves these
standards and this playback quality all the way from the source image in the
camera to the destination display.
HD in video conferencing
Most traditional video conferencing systems use dedicated
hardware and connections to support HD. But as web conferencing
products have moved up the chain toward that video conferencing
market, high-end camera and display prices have dropped and
web-based video conferencing has come to boardroom meetings,
company all-hands gatherings and telemedicine applications.
The problem lies in getting true HD quality out of low-end
equipment. Even with the general improvements in cameras,
processors, displays and network bandwidth, delivering HD
through desktop products is not as simple as plugging in new
devices, as shown in this diagram:
Each link in this chain presents a potential source of
latency or data loss, and some web conferencing products
"stretch" the video to compensate for the lower resolution or
fewer frames per second introduced by their approach to HD. But
if the quality of hardware used is inadequate, or if any link in
this chain does not support HD, then the resulting video cannot
The camera must capture video at the resolution and frame
rate desired for the destination display. In the context of
business-to-business (B2B) video conferencing, "HD" generally
refers to 720 (1280 x 720 pixels) or better.
HD: Conference room cameras and HD cameras
use high-quality lenses and electronics to generate video
natively in high definition.
Not HD: Some USB-based Web cameras can
capture and move enough pixels for 1280 x 720 resolution, but
because they are not generally designed for HD, they sacrifice
frames per second and thus do not meet the true HD
specification. The advent of USB 3.0-ready cameras may change
this (see below).
For true HD, look for:
• Conference room camera or HD camera
• Web camera that supports USB 3.0 (eventually)
Nefsis supports the resolution and frame rate of conference
room cameras and HD cameras all the way from image source to
destination display. See
HD Video Capture for more details.
The Capture Card
The image from the HD camera is captured and encoded using
H.264. The data is then relayed to all users in the conference.
This extremely compute-intensive work requires processing power.
HD: Conference room cameras and HD cameras
perform the work on dedicated hardware in the PC. They connect
via HDMI cable or BNC connector to a capture card running an HD
codec (encoder/decoder) on its own chipset. The card then sends
the image into memory across a high-speed PCI or PCI Express
Not HD: Most Web conferencing products try
to emulate the hardware function in software running on the CPU.
Rather than use a capture card, web cameras send the HD signal
into memory over USB to a software driver specific to the
camera, then use a software-based codec running on the CPU to
convert the image. This saves the cost of the capture card, but
software emulation on the CPU is slower than dedicated hardware
and does not duplicate the quality of true HD. As a result,
these products take shortcuts, such as capturing a smaller
original image and stretching it, or reducing the frame rate.
The image size at destination may be 1280 x 720, but the quality
of HD is missing.
Eventually HD: USB 3.0 promises theoretical
speeds of up to 5.4Gbps, which will suffice to move data from a
web camera into memory at rates fully compliant with HD 1080p. As
USB 3.0-ready web cameras come to market, conference
room cameras will continue to distinguish
themselves with higher-quality optics and features like
pan-tilt-zoom rather than resolution and frame rate.
For true HD, look for:
• Cameras that use dedicated hardware (PCI/PCI Express) in the
• HDMI or BNC connection to the computer
Nefsis preserves the resolution and frame rate of the image
generated by the camera, whether the image comes from dedicated
hardware or from software emulation.
Encoding on Source CPU, Decoding on Destination CPU
Video conferencing software takes the HD video at the source
CPU and encodes it for transmission over the network. At the
destination CPU, it decodes the video and hands it off for
display. While this task does not require specialized hardware,
it is a function that benefits if the software can take full
advantage of multi-core CPUs, MMX/SSE extensions, parallel
processing and symmetric multi-processing (SMP).
HD: Boardroom-type video conferencing products include
dedicated hardware for encoding and decoding HD at both ends;
the technology is built into them.
Not HD: Web conferencing products can handle low-resolution
video, but without the technology to accommodate the HD video
produced by video conferencing cameras, their performance is
lower and the resulting image is not – cannot be – true HD, as
video conference participants will quickly notice.
For true HD, look for video conferencing software such as
Nefsis that takes advantage of multiple cores and CPUs, as well
as their extensions, when available.
Nefsis takes the HD video stream, intelligently distributes
the work of encoding and decoding it among multiple CPU cores
and extensions, and processes it without any modification or
As the video goes from the source computer over the network
to the destination computer(s), compression and network
throughput come into play.
HD: The encoded HD video stream is too large
to send over most networks efficiently. Video conferencing
products compress the stream intelligently by comparing each
frame to the previous one and sending only the bits that have
changed. Also, properly handling HD requires network speeds of
at least 1Mbps sustained; otherwise, the network becomes a
bottleneck. Wi-Fi and broadband connections may not suffice.
Asymmetric connections with high downlink bandwidth but limited
uplink may not suffice, either.
Not HD: Most web conferencing products rely
on standard video codecs, which can result in too much data for
the network transport layer. Thus, the network becomes a gating
factor in delivering the HD signal from source to destination.
For true HD, look for:
• variable bit encoding to compress the video stream
intelligently before sending it to the network
• 1-4 Mbps of sustained network speed
Filling up a 47-inch, wall-mounted monitor in a conference
room with high-quality video is more demanding than filling up
one-fourth of a screen in a 15.6" monitor. Also, displaying a
high-definition, 1920 x 1080 video is more demanding than
displaying nine low-resolution, 640x360 videos.
HD: An HD image that has been preserved from
camera to destination display will allow for full resizing to
original resolution with no pixilation or compromise in frame
Not HD: An image captured by a USB web
camera may be satisfactory in a small window on the destination
display. It's possible to resize the window to 720 or 1080, but
degradation will be apparent: pixilation, choppy motion, jagged
For true HD look for:
• monitors that meet or exceed 720, such as WXGA (1280 x 800)
and SXGA (1280x1024)
• monitors that are a superset of 1080, such as WUXGA
(1290x1200). A WUXGA monitor can display HD video and still have
room for desktop features like the system tray and other
As applications for video conferencing continue to
proliferate, and as web conferencing software brings online
meetings within the reach and budget of more organizations, the
opportunity for HD in these meetings will grow. Still, there is
more to introducing HD than simply purchasing a camera which
claims to support it.
On the long chain between source camera and destination
display, every software and hardware link must preserve the
integrity of the HD image. Otherwise, the resulting image may
suffice at low resolutions and frame rates, but will disappoint
at true HD size.
a quick walk-through of Nefsis HD video conferencing
capabilities right from your own desk, click
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HD Video Conferencing — HD specifications and more Nefsis screenshots
Video Conferencing Equipment — Webcams, HD cameras and other Nefsis compatible equipment
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