Sunday, February 5, 2012


What is Webcasting?
  • Webcasting is a tool for communication. It brings together the immediacy of television broadcasting with the interactivity and accessibility of the Internet. Webcasting is a way of delivering recorded and live audio and video content over a network (usually the Internet or intranet).
  • Streaming media is another term for this process
  • Video, audio and other media content such as PowerPoint slides with graphics can be linked and then webcast so that they are accessible to large audiences from their desktops in a form of complete multimedia presentations presented on consoles.
  • Live events as well as pre-recorded material can be webcast (live and on-demand webcasts).

What is webcast and what is involved in webcast?

A webcast is a digital broadcast over the Internet where video & audio of the live or pre-recorded event is delivered directly to the end-user’s computer for real time or archived on-demand viewing. A webcast is commonly accessed from the website and the end-user is required to have Internet connection, (preferably a broadband Internet connection for the best experience) Internet browser and media player. Webcast delivery steps are:

1.      Video & audio feed is acquired from audio/video sources

2.      Video & audio feed is converted into Internet delivery format (i.e., windows media format) - this process is also known as encoding

3.      Encoded media is acquired by a streaming server

4.      Links are posted on the website

5.      When end-user clicks on the link, streaming server delivers the live/on-demand feed to the end-user's computer

6.      End-user can view the media on computer, portable device or phone.

Managed webcasting brings all of these steps under one end-to-end solution, providing your company with the ability to broadcast your media to customers with one complete interface.

The technology behind webcasting is streaming audio and video. That means RTP (Real-time Transport Protocol) over UDP (User Datagram Protocol) in most cases. These technologies are outlined under "Multimedia" along with related technologies.Webcasting is also called "netcasting," "Internet broadcasting," or "data broadcasting," although webcasting is more associated with streaming video and audio. Data broadcasting is more about sending news, stock quotes, and related information to subscribers using "push" techniques. Push is the opposite of "pull," which is what you do when you access Web site. With push, Web sites automatically send you information. E-mail is a push techniques that people use to send other people information, sometimes without the recipient asking for it. Think of push in terms of low-bandwidth data broadcasting (stocks, news, sports headlines). Think of webcasting as full multimedia broadcasting.
The ultimate webcasting technology is multicasting, which is based on special Internet protocols that deliver content along efficient paths from the sender to multiple receivers. The idea is to send packets only along paths that lead to subscribers of the multicast information, thus cutting down on traffic. See "Multicasting."
The webcasting community even has its own organization called the International Webcasting Association. Its Web site is listed on the related entries page. The IWA serves companies that are active in the delivery of multimedia (audio and video) services to consumers or business customers via the Net and other networks. Another association is DiMA (Digital Media Association).
Webcasting Sites and Services
One of the best examples of webcasting is Yahoo! Broadcast. Yahoo! purchased to acquire the webcasting technology. The site can be accessed at It is described as a place where businesses and content providers can deliver corporate communications messages via audio and video streaming. Applications include product launches, press conferences, e-learning, seminars, keynote addresses, annual shareholder meetings, quarterly earnings calls and corporate TV channels. Services include the following:
  • Webcasting services such as live and on-demand audio and video broadcasting, pay-per-view broadcasting, secured broadcasting, and multicasting services
  • A/V production services, such as live webcast engineering, audio/video production, and satellite connections
  • Web and multimedia development, such as synchronized multimedia and front-end interface development (registration, polling, surveying, testing)
What is Streaming Audio?
Streaming Audio a method of playing audio files from the web. The audio is played as it arrives off the Internet. The file is not preserved on the computer, so an internet connection must be sustained to play the audio file.  In simplest terms, it's an audio signal, carried to your computer by the wonders of the internet.  It can be either "live" or "archived" (saved at a website for later listening).

What is Streaming Media?

  1. Streaming Media Definition
In contrast to the download-and-play technology of a short time ago, streaming media has become the norm for audio and video over the web. Streamed media is displayed to the end user as it is delivered over the network in real time. A few seconds of latency at the beginning of the delivery is the only wait, whether the clip is large or small. Compression (using codecs to analyze the content to decide what bits of data can be removed or merged with minimum impact to what you see and hear) is used to accomplish the speedy delivery.
The advantage of streamed media is that you don't have to wait to see or hear your media. The disadvantage is its quality may degrade as it is streamed because streaming software adjusts to changes in line speed, dropping frames as it needs.
Because of this, using download-and-play video for clips of 30 seconds or less using AVI or QuickTime may still be a viable alternative.
  1. Three Major Media Forces:
    • Microsoft Windows Media Services (Formerly NetShow Services)
    • RealMedia (RealNetwork's RealAudio/RealVideo)
    • QuickTime
Most media can be streamed now with or without the encoded file residing on a streaming server. The advantage of using a server to stream media is that there is more control over content and bandwidth and usually a faster service. Microsoft and RealMedia are two that have used streamed server applications for some time. QuickTime has just recently release a server product.
Windows Media Services on a dedicated streaming server is being used here for a number of reasons: the product is free with Windows NT Server, the player is widely available, the tools are easy to use and the end result compares very well to the other media applications. It uses what it calls Active Streaming Format (ASF) for its streaming content. It allows you to create mid- to low-end streams for Internet projects. NetShow Theatre Server is an add-on product for high bandwidth, Intranet projects. There is an add-on license fee involved with NetShow Theatre.
  1. Components of a Streaming Media Solution:
1.                  Web streaming server
      • Installed on a web server or multiple server configuration, separate from the HTML web server
      • Allows for bandwidth control
      • Need high speed ATM network connection
    1. Media production computer
      • Capturing components (capture card and software, VCR, video camera, etc.)
      • Video editing software
      • Encoding and Scripting tools and other utilities
    2. Disk space
      • Lots of it, for both the server and development computers
    3. Client Needs
      • Browser media player (Microsoft Media Player) - free
        (Plays WAV, MIDI, MP3, MPG, RealAudio, RealVideo, QuickTime and more)
      • Multimedia computer, minimum sound card with speakers

  1. Streaming Media Delivery Techniques
0.                  Unicast - two-way, on-demand connection to a stored resource
      • The user can use the player controls to pause, skip or restart
      • The most used and most bandwidth consuming technique
    1. IP Multicast - a single copy of the data is sent over the network simultaneously to multiple clients
      • The user cannot control content
      • Uses less bandwidth consumption than Unicast
    2. Live Streaming - from microphone, video camera, or other source
      • The user cannot control content
      • Uses the least bandwidth consumption
  1. Streaming Delivery Quality
The display quality a client gets from a stream is dependent on the end-user's computer and connection, network bandwidth, and network congestion. Streaming a LAN quality clip over a dial-up connection will result in broken reception. You must identify your audience before deciding on a delivery method and quality bit rate format.
Target Bit Rate Formats for Windows Media Player Encoding
    1. 28.8 (Actual 22 kbps)
    2. 56 Dial-up modem (Actual 37 kbps)
    3. 56 ISDN (Actual 50 kbps, good for general audio over LAN)
    4. 100 Video (Intranet or LAN, hi-motion for presentation) 300 Video (Custom) 512 Video (Custom)
Streaming video. Streaming multimedia allows the user to begin viewing video clips without first completely downloading the entire file. After initial buffering, the file begins to stream, or become available for viewing through the player software. Video quality is highly dependent on bandwidth and processor speed. Streaming video is unicast; that is, each user is sent a separate video stream from the host server.

What Is MP3?

Downloadable music formats like MP3 and streaming audio on the Internet are revolutionizing the way music is distributed and consumed. With these technologies, consumers have more convenient access to a wider variety of music and more control over how they listen to it. Musicians have increased access to fans and more options for distributing their music. Independent record labels have a better way to promote and distribute music to a wider audience. And the major record labels have a serious threat to their dominance of the industry.
MP3  (technically, MPEG Audio Layer-III ) is a standard format for compressing digital audio . MP3 squeezes audio files to about one tenth of their original size, while maintaining close to CD quality. Songs in MP3 format can be downloaded from the Internet, created from prerecorded music, or recorded from scratch. They can be played on personal computers, Walkman-style portable players (like the Rio) or one of the new generation of dual-mode MP3/audio CD players.

What Is MPEG ?

MPEG  stands for Moving Picture Experts Group. The MPEG committee works under the direction of the International Standards Organization (ISO) and establishes standards for encoding audio and video in digital format, and for interactive graphics applications. MP3 is just a small part of the MPEG family of standards. Thanks to MPEG, we also have standards for technologies like DVD (Digital Versatile Disc) and DirecTV.
 The main benefit of MP3 is its high level of compression, which makes for smaller files and faster downloads. With MP3, you can store more than 12 hours of high-quality music on a single CD, versus the standard 74 minutes. With the matchbook-sized memory cards used by portable MP3 players, you can fit the equivalent of a dozen CDs in your wallet. (I verified this by putting some SmartMedia cards in my own wallet.)
MP3 compression allows you to use your computer as a digital jukebox that can hold thousands of CD-quality songs. You can quickly find and play any song with a click of a mouse and never have to worry about tapes wearing out or records getting scratched. Instead of spending hours making tapes or programming a CD changer, you can compile customized playlists in minutes.
Compression  also makes it practical to download music from the Internet, where you can access thousands of songs from artists all over the world. With MP3, you can download a four-minute song in less than 15 minutes (with a 33.6 kbps modem), compared to more than 3 hours for the same song in CD audio format. Now you can sample a wide variety of music from the comfort of your home and find some great music from independent artists you might not otherwise be exposed to.
MP3 opens up a whole new range of possibilities for musicians. If you are an independent or emerging artist, MP3 and the Internet give you a low cost way to promote your music worldwide and keep in touch with fans. You can sign with one of the new Internet record labels , retain the copyrights to your music, and keep a much larger share of the revenue.
Downloadable music and streaming audio are rapidly growing in popularity, but widespread acceptance has been limited by the fact that these are relatively new technologies, and there is a shortage of people who understand them. There’s also a lot of hype and contradictory information about coming from many different sources. There’s confusion about terminology, debates about sound quality, and concern about the ease with which unauthorized copies can be produced and distributed.

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