Webcasting 101

The best explanation of the Streaming/Webcasting process on the web, copied by many other's, authored by Brian J. Isaacson of Communitek Video Systems.

How to do a Broadcast style Webcast:

In order to produce a Webcast for Internet (or corporate Intranet) distribution, you will need to answer the following:
How many viewers in the target audience and what bit-rates (streaming quality)?
(ie...1.5MB/s, 1 MB/s, 768KB/s, 500KB/s, 350KB/s)

This will determine two things:
a. The number of simultaneous streams
b. The required bandwidth on the server side.

How do you intend to host the live

a. Communitek Video Servers (a.k.a. communitek.tv)
b. Another hosting company capable of supporting the required bandwidth and has the necessary equipment
c. Have or are purchasing Streaming Servers from Communitek and have your own dedicated bandwidth.
d. Already have Streaming Servers on your own Network.

Once you have determined how you will host the Webcast, we need to know how you will reach the hosting server(s)
a. Have or plan to have a high "up-speed" Cable Modem, DSL Line, or other high-speed internet connection with either dedicated IP's or dynamic (DHCP) IP's, at the webcast venue.
b. Only using a LAN system, ie...corporate in-house intranet

Now that we know you can reach the server(s), we can turn to the actual equipment and facilities needed to produce the live streams. You will need a Webcaster or Streaming Video encoder, either by:
a. Renting a Webcaster, Minicaster, or MiniMobile from Communitek.
b. Purchase or lease a Webcasting Encoder, such as the Webcaster-3, Minicaster-HD, or MiniMobile.
c. Already have your own Webcasting Encoder, and just need hosting service.

The choice of Encoders is also determined by the format you intend to use:
The choices are: Flash, h.264 (MP4), HLS (iPhone/iPad/Droid), Windows Media, or Real Media. Each has it's pluses and minuses, as well as associated costs. The two most preferred are Flash and HLS (Hypertext Live Streaming) These are the most popular type of streaming video protocols. Communitek is all tooled-up for Flash, h.264 and WMV, with the appropriate servers and software. Many hosting services are also set-up for Flash and WMV. And, although we can provide an encoder for Real Media, this format requires special Helix servers, which Communitek does not support.

MPEG-4 (MP4), has become the most popular archive file type, to date. The native streaming format for MP4 is h.264. All of Communitek's encoder products come with h.264 encoding, and can either record locally and/or record to our streaming servers in MP4 format. One of the great benefits of using h.264/mp4, is the reduction in bandwidth that results from the compression algorithm, vs. other formats.
HLS is the required format for iPhone/iPad, however HLS is a segmented derivative of h.264, thus our servers have the capability for streaming simultaneously in h.264 and HLS, which allows virtually any computer based device to view the live and on-demand streams. This format has many applications, including true broadcast quality over web, and point to point video streaming. Call for more details on MPEG4.

The popular Flash streaming, by Adobe, is available as h.264 or the original .flv file type. Most Flash streaming is executed as h.264, which again allows us to stream to both Flash and HLS type players.
Flash/h.264 is the preferred streaming format by video hosting companies, such as YouTube, Vimeo, and many others. The big advantage of using Flash with h.264, is that it works cross-platforms In other words, both PC, MAC, iPhone, iPad, Droid, when hosted on CDN's that have real-time transcoders, such as Communitek.TV. For Windows Media (WMV), although there is a protocol for h.264 known as "Smooth Streaming, and a plug-in for MAC, known as Silverlight, some users are reluctant to actually download the plug-in.

The next step is to determine what production video/audio equipment you need for the venue or location of the webcast:
Communitek provides the following products for production:
Broadcast and Industrial Quality Cameras
Broadcast Quality Switchers, Keyers, and Logo Generators
Audio Mixers and Processing Equipment
Lighting, Mics, Mixers, and other productions peripherals
Referrals for Production Crews
Video Hosting Services for Live and on Demand Streaming
Video Archiving Software for Video Asset Management
Web Conferencing Software that combines Video and Slide Pushes

Lets Start with the Cameras:
The video quality pushed out to the world wide web is not going to be better
than the bandwidth used, so using $30,000 broadcast quality cameras is
overkill. However, for material that will be streamed and simultaneously
archived to a broadcast video format, does require a broadcast quality, or
very good industrial quality camera. Communitek is a supplier of Ikegami,
Sony, and Panasonic Cameras for Broadcast and Industrial systems. These
cameras range in cost from $3000 to $15,000. Low end consumer cameras,
although not recommended, can be used as sources for live streaming but will
not have the resolution of professional or industrial grade cameras. We can supply conference style Pan-Tilt-Zoom cameras.
Conference cameras, with remote control which run about $1200. For Webcasts
that will be archived to DVCam, Betacam, Digital Betacam, or other high
quality formats we recommend starting with cameras in the higher range. For
Webconferencing or meeting events, where the quality is not critical, you
can use the lower cost cameras.

Switchers for Multi-Camera Webcasts:

A Video Switcher is required, if you need to select multiple video
sources, such as cameras and character generators, to produce one video
signal for the web stream. If you already have a video switcher that is
compatible with the cameras and other video sources you are using,, then
you would only need to feed the composite or s-video, or SDI output of
that switcher to our webcaster. If you don't have a switcher, we have a
few very good switchers for live Webcasting.
The Webcaster3 integrates the VidBlaster Switcher with the right hardware for live HD switching abd is ideally suited for Webcasting..For up to 8 cameras which have any combination of HD-SDI, HDMI, DVI, VGA, Composite or S VIdeo inputs. This switcher has full Frame-Synchronization and Des-Interlacing on all inputs.

Audio Sources for the Webcast:

The most common audio source for live webcasting are microphones,
CD player, and MP3 sources. With any number of microphones and other
sources, you will need some form of Audio Mixer. The Mixer serves not only
the functions of mixing various audio sources, but also brings the
overall audio level up to "line level", which is required by the
Webcaster. The exception is our Minicaster, which has one stereo audio
input which can be set to microphone or line level. For webcasts where an
auditorium is being used, or there is already a "house mixer", you
may be able to simply pull a feed from the existing mixer. The line level of
the Webcaster will accept anything from -10db to +4b for both audio inputs
(left and right or channel 1, channel 2). The Webcaster can be set-up to
take one (mono) audio signal and distribute the audio over the stereo pair,
for the stream, or you can discreetly feed each channel. The inputs on the
Webcaster-3 are XLR balanced audio, and the Minicaster has un-balanced
input. Communitek has an assortment of audio mixers, if needed to work with
either the Webcaster-3 or the Minicaster systems.

Getting the Stream(s) on the Web:

The Webcaster-3, Minicaster-SD and Minicaster-HD products, developed by
Communitek, provides the means to stream live video, audio, and graphics
to viewers via the Internet or a private Intranet.

The Webcaster-3 is
an integrated live streaming video encoder, built into a flight case,
which is portable enough to ship from location to location, yet houses a
very powerful Streaming Video Encoder System. This device is packaged
with Audio processing, BNC video Input, an the necessary software to
produce WM9, MPEG4, and /or Real Encoding. The Webcaster 3 can take one
video source or video from a switcher and produce up to three different
bit-rate streams, which can then be uploaded to a server for
distribution on the internet (or an intranet).

The Minicaster-SD
and Minicaster-HD
are the latest Communitek Encoder webcasting products. These streaming video
appliances are compact systems designed for quick
set-up of live webcasting, which can be integrated to other peripherals
such as switchers and graphics generators. All three units are
pre-configured for the customer's needs and pre-tested prior to

The output connection of the Minicaster or the Webcaster require a
high-speed internet or intranet connection to be directed to the servers
that will host the streams (see next paragraph). You will need to have
either "T1" Service, which is a 1.5Mbs internet line with
dedicated IP addresses, or what is know as S-DSL (symmetrical DSL,
meaning it has the same "up" speed as download speed, much
like a T1). The S-DSL line must be at least 768K for a single stream. If you are encoding multiple streams, you will need a T1 line at the
minimum. The exception is, if your are using a corporate LAN to webcast,
which has adequate bandwidth. You can stream very high quality video over LAN,
as long as you are not conflicting with normal internet/intranet traffic.

Hosting the Live Streams

In order to reach your audience, Servers are employed which relay the
streams generated by the Webcaster or Minicaster to the viewer's desktop. Video Servers,
as we call them, are very high end Server computers, which are located on a
wide bandwidth internet (or intranet) connection. Communitek maintains such
server on the East Coast of the US, with a bandwidth capacity of several
hundred GB, and our capacity is enhanced by edge servers located through
the world, servicing a multitude of users. The choices for end
users are either to purchase servers, lease servers, or rent bandwidth on dedicated hosting servers, such as Communitek Video

Multiple Live Camera Sources:

With the Webcaster-3, and Communitek's multi-cam software
(installed on the servers), you can have up to three dedicated cameras,
streaming simultaneously, and allow the viewer to switch the video source on
his/her computer. This technique does require that the servers be configured
by Communitek, and there are specific bandwidth requirements, depending on
audience size. For this type of streaming video set-up, consult Communitek
for details and pricing.

Adding Slides and Graphics to my Webcast

Communitek has special software that enables slides, such as jpeg's, gif's,
bmp's and other graphics to be simultaneously pushed out, though the server,
to the audience. Thus, an administrator, running the Webcast, can select
slides to push out to everyone's desktop, who is viewing the live Webcast.
This product is called VNC (Video Network Connect), and requires additional
server, other than the Video Server, with custom web pages written for your
particular Webcast.

Archiving Content

All Communitek Webcaster and Minicaster products have the capacity to record and store the
live video webcast on their own hard drives. The encoded files can be
archived locally and/or uploaded to hosting servers for Video-On-Demand(VOD). You may want to consider hosting the recorded
content, by uploading to
Communitek's hosting servers or to your own
servers. Thus, videos can be archived for later VOD playback and viewed by your audience. Communitek also has two video
archiving and
retrieval programs, called Archive and Archive Lite, which allows content to
be browsed, searched, and played.

Thank you for considering Communitek Video Systems, Inc. for your video
streaming and webcasting needs.

If you have questions, please feel free to call Communitek Video Systems @
212-967-1774 or Click Here to Contact Communitek