Copyright ©1996, Que Corporation. All rights reserved. No part of this book may be used or reproduced in any form or by any means, or stored in a database or retrieval system without prior written permission of the publisher except in the case of brief quotations embodied in critical articles and reviews. Making copies of any part of this book for any purpose other than your own personal use is a violation of United States copyright laws. For information, address Que Corporation, 201 West 103rd Street, Indianapolis, IN 46290 or at support@mcp.com.

Notice: This material is excerpted from Running A Perfect Web Site with Apache, ISBN: 0-7897-0745-4. The electronic version of this material has not been through the final proof reading stage that the book goes through before being published in printed form. Some errors may exist here that are corrected before the book is published. This material is provided "as is" without any warranty of any kind.

chapter 19 - Interactive and Live Applications

 In previous chapters, you have explored Web interaction on the most basic of levels: htmL file transfer, forms, usage counters, and other elemental forms of information exchange. This chapter is devoted to the exploration of the next generation of interactivity and the advent of the live application, those applications that integrate aural and visual response or information exchange.

The first section of this chapter examines the state-of-the-art for audio and video usage in interactive and live applications and advanced interactive concepts, such as live video conferencing. Commercial and noncommercial applications, tools and peripherals, and sites for both resources and interaction are described or provided.

The second section of this chapter presents techniques for expanding the interactivity of the Web. This section includes discussions of the proposed methods for implementing new interactive concepts, such as Auralview, W3Vision, and WebStage sessions. It also covers the fast growing area of virtual reality interactivity.

Your vision of this new interactivity is not limited to only existing technology. You do turn outward and examine where you can go and what the near and not-too-distant future may have in store for those who travel the Information Superhighway.

In this chapter, you learn about:

  • Live applications to add multimedia to your Web site

  • Tools for implementing advanced interactive applications

  • Virtual reality engines and applications

  • Resource sites for sound bites, video clips, and more

Interactive and Live Application Concepts

This section examines state-of-the-art audio and video toolsets and development technology, interactive applications, and example sites. Some advanced interactive concepts under discussion are: audio and video servers and clients and real-time video conferencing. Commercial and non-commercial tools and peripherals, applications, and sites covering both resources and example interaction will be described and/or provided.

To enjoy a firm footing in the coming discussion, it is necessary to have an understanding of certain basic concepts. Within this section, the concept of server and client appears. It is not unlike the standard references to client/server in use today.

A server is a system that consists of both hardware and software that can offer an exchange of information and access to the services, software, or supplies required by the server's Web site visitor. Because the information transactions that are described in this section are audio, video, or a combination of both, the amount of information that needs to be exchanged is usually quite large. Add to this the security issues involved and because some of the servers on the Net are actually companies or organizations that are in the business of supplying these information transactions for a fee, the necessity arises for a controlled method for accessing this information - the client.

The client is also a combination hardware and software system. The software application is responsible for any security or access issues, but must also provide an acceptable method for transferring large files across the Net in a timely manner. The problem is greatly enhanced for applications that transfer large amounts of information that must be delivered in real-time.

Hardware issues also determine the lag time encountered with these transactions. Even having the highest speed connection (ISDN or T1) doesn't ensure that a timely transaction can occur.

During the design phase of your Web site, it is imperative that you define what type of hardware and software you expect your users to have. This will aid you in developing the look, feel, and content of the information you supply.

The toolsets, resource sites, and information supplied in this section deal with these subjects as necessary.

Audio Tools/Applications and Example Sites

One of the most popular options that you can add to your developing Web site is streaming or on-demand audio. On-demand audio allows visitors to your site to have access to audio that is transferred across the Net at speeds that allow the visitor to listen to audio in real-time.

How do you supply audio in real-time? The secret to transferring the vast amount of information required for real-time audio is to use data compression techniques. This is a fast developing area of Internet technology and there are several methods that can be used to accomplish compression.

However, prior to selecting a satisfactory compression technique, it is imperative to ensure the quality of the audio offered to your Web site visitor. Taking a simple series of steps can ensure that you develop a high level of quality for your audio.

The First Step to Quality Audio

There are a few simple rules that you should follow to achieve the highest quality sound. It is very important to achieve a high level of quality because, as you will read shortly, the method that you use to encode the audio permanently alters the quality.

Use a High-Quality Original Source and Quality Equipment
Perhaps the single greatest factor in determining the level of audio quality is the audio source. The source that you use is determined by the equipment available to you. Some of the best sources of quality audio are:

SourceQuality Level
Audio compact discs (CDs)High
Digital audio tapes (DATs)High
Analog cassettes (pre-mastered)Medium
Vinyl recordsLow

To develop quality sound from scratch, you can use:

SourceQuality Level
Professional high-qualityHighest quality microphones
Condenser microphonesLowest quality
Professional recording Highest quality equipment or facilities (i.e., multichannel recorders, sound rooms, mixing boards)
Home variety recording Lowest quality equipment or facilities (i.e., cassette tape recorders, bathrooms, ironing boards)


One of the best resource lists for professional audio equipment can be found at http://www.magicnet.net/rz/world_of_audio/gear/gear1.html.

Try to encode your audio from 16-bit source files that were digitized with a 22.05 kHz sampling rate. Most compression techniques accept multiple other forms of source files (such as 8-bit or æLaw).

When you're creating audio sources, keep in mind that you can use any production resource. However, the encoding done by the compression algorithm can cause hiss and distortion.

Source files that were recorded at either 8000 Hz or 11000 Hz are also acceptable, but, once again, remember the favorite saying of computer geeks everywhere - GIGO (pronounced guy go), which stands for Garbage In, Garbage Out. If you want quality, start with the optimum quality available.

Remember, high-quality equipment will produce high-quality results. This is true for every element in the recording chain, from the input source to the audio capture device to the software used for capturing and editing. A little forethought about your audio source file's origin can save you headaches down the road. If you intend to provide commercial audio services at your Web site, you ought to invest in professional audio equipment. This type and level of equipment doesn't have to break your piggy bank, but it is professional equipment that should be acquired from a professional recording equipment dealer, rather than from a fly-by-night Gadget Supply or your local computer/hi-fi/appliance store.

Control the Recording Level
Create an audio source file for use on your Web site by using an internal sound card. There are many manufacturer's of sound cards on the market. One of the Creative Labs' SoundBlaster is the de facto standard for the industry. Selecting the type of sound card you use should be based on the criteria previously listed concerning the quality of the audio source file required and the type of computer system that performs the sound capture.


One of the best resource lists for audio equipment and other sources is located at http://www.music.mcgill.ca.

Regardless of which card you use, setting the correct level of input to your sound card is critical. When an input signal exceeds the full range of amplitude available to your sound card (or any other piece of audio equipment), the result is a level that crowns the input amplifier. Crowning the input amplifier causes a flattening of the input that results in a clipped signal. Clipping is audible in the resulting source file as a high frequency, crackling noise.

Digitizing with your sound card requires a simple but methodical approach to achieve the finest, quality results. Using your selected audio source, you should perform several test runs adjusting your input level until it approaches but doesn't exceed the maximum level for the sound card input amplifier.


Most sound card manufacturers supply a set of utilities that perform specific tasks on their card. The input level of the various sources of audio being supplied to the sound card can usually be adjusted using a mixer utility.


Look for an adjustment labeled Input Level or Recording Level. Most mixer utilities use some sort of visual display to provide you with either the level of sound coming in or a paddle control that is used to adjust the sound level. Ensure that no peaks above maximum occur. Generally, these excursions are indicated by a red light or red band in the case of Visual VU Meters. Be conservative with your level adjustments; you never know when an unexpected volume increase can occur.

Audio source files that do not use the optimum range of input amplitude ultimately produce unsatisfactory compressed files.

Digital Audio Editors
Once you have either created a sound file or received a sound file, you can manipulate and edit this file using a Windows-based editor.

In addition to your sound card manufacturer's set of utilities, an Audio Editor can be used to correct for errors that may have crept into your audio source file. An amplitude range that is too low can be increased or normalized, hisses and pops and other forms of distortion can be erased and the overall time of the audio recording can be changed. You can also change the file to add sound effects and even merge multiple sound files together.

Transmission Bandwidth versus Audio Type
Live audio compression techniques optimize compressed files according to the type of audio recorded and being transmitted. Speech delivery can usually be performed adequately at a transmission rate of 14.4 Kbps. Delivering music at 14.4 is a much more difficult challenge.

Encoding music for transmission to users that are connected to the Internet at 14.4 Kbps requires forethought in your music selection. It is important to remember that when transmitting audio, or video for that matter, a certain amount of bandwidth is required to do the original source justice. Transmitting a live version of the Podunk International Symphony Orchestra's version of Rossini's Overture to William Tell might be a wonderful service your Web site could supply; however, if you attempt to transmit this harmonically complex signal over a 14.4 Kbps modem, you cannot do the piece justice. Applications where the ultimate fidelity of the music is not as important as other content, such as using music as a background for advertisements where the vocal message is the primary purpose of the audio source, result in a much more successful application.

As you can imagine then, using a system that uses 28.8 Kbps analog modems or ISDN and T1 digital modems, result in higher bandwidth and, therefore, in greater capabilities. Increasing your bandwidth allows for greatly improved frequency response, a greater dynamic audio range, and a decrease in the number of artifacts, those holes in a decompressed file that cause audio noise and video flutter.

The Second Step to Quality Audio

Creating compressed files that meet the requirements discussed in the previous section requires the use of quality software that can encode the files using algorithms that make guesses as to what is most important in the audio source file. The algorithm encoder contains a predefined list of elements within a sound stream. All elements are weighted against each other and then are used to modify the stream according to each element's weight. The common elements used by encoders consist of the following:

  • Transmission Bandwidth - usually either 14,4 Kbps or 28.8 Kbps

  • Audio Compression

  • Audio Equalization

  • Noise Gating

  • Audio Normalization

Transmission Bandwidth
As previously discussed, the transmission bandwidth is selected when you are determining what type of audio sources you plan to offer as a service. The encoding software uses this information to determine how much time it has in which to put the preprocessed audio source information. The overall reproduction fidelity and quality of your decompressed [expanded] files will be determined by the bandwidth available for determining various audio signal qualities.

Audio Compression
Have you ever noticed a weird rumbling noise, low frequency hum, or other strange form of distortion in an audio file that you are playing? The cause of that sound is not faulty playback software or cheap hardware, rather it is due to a side effect of encoding/compressing an audio signal - an artifact. This is a sound that wasn't there before encoding, or compressing.

The suppression of audio artifacts is one reason that you want to supply the loudest signal possible to your sound card. Audio artifact signals are relatively low volume sounds. It doesn't really matter whether the original sound file was loud or quiet. Louder files tend to mask artifacts. Although your desire is to supply the loudest source file possible to the compression algorithm, you are limited by the amplitude of the loudest sound in the source. It only stands to reason that if you could control the variation between the loudest and softest signals you were compressing, you could effectively turn up the overall volume of the source file. This is where audio compression techniques enter the picture.

Audio compression reduces the difference between the loudest and softest areas of an incoming source file. What the audio compressor does is to use a predefined threshold to determine which input signal levels should be turned down and which should be left alone. How much control there is for turning areas of the source signal file up or down depends on how much compression is used.

Compression guidelines are rough at best and algorithmic guesses are based on years of experience. There are general rules-of-thumb, however, that should be helpful in most situations:

  • Speech compression ratios at 14.4 Kbps - moderate to extreme, 4:1 to 10:1. This guarantees that the signal is loud enough to mask artifacts that are more apparent at this transmission rate

  • Speech compression ratios at 28.8 Kbps - low to moderate, 2:1 to 4:1. With a transmission rate of 28.8 Kbps, the dynamic range is greatly increased and the artifacts greatly reduced.

  • Music compression ratios at 14.4 Kbps - moderate to moderately high, 4:1 to 6:1. Again, determined by the increase in artifacts and also the limited dynamic range of the supported audio.

  • Music compression ratios at 28.8 Kbps - extremely low to moderate, 1:1 to 3:1. With the greater dynamic range, even a symphony orchestra would reproduce excellently.

Noise Gating
Noise gating is a function of audio compression. Simply put, it is the act of eliminating unwanted background noise that becomes audible during gaps in an audio signal. As in audio compression, noise gating is determined by setting a specific volume level above which signal amplitude is left alone but below which the signal is turned down or off. Even the least expensive compressors usually have some form of noise gating built in.

Audio Equalization
Equalization is a bit of a mystery to most people. Even though their automobile and home audio systems usually have some form of equalization control, most people have no idea what equalization is meant for or how to determine what changes to make in the settings that came set from the factory.

Simply stated, equalization changes the frequency formula of an audio signal. This is accomplished by boosting (turning up) or cutting (turning down) certain frequencies or frequency ranges. Ultimately, equalization is meant to compensate for frequency variations in the surrounding space. The response characteristics of your apartment or your car can be compensated for by using equalization. In addition, using specialized equalization systems, you can also compensate for some slight variations in the flat response curve of your speakers.

Attempting to use equalization for its intended purpose with sound files that you intend to supply over the Net is ludicrous, at best. However, you can use equalization to control another aspect of an audio signal - clarifying the signal. Clarifying the signal is essentially suppressing or filtering unwanted background noise or annoying frequencies. Using equalization, you can boost frequencies where the important content is and cut frequencies where the noise or unwanted sound is.

Some simple equalization systems only define ranges that it offers equalization for (that is low-, mid- and high- range). Some systems allow you to choose which frequency to boost, other systems are preset at the factory. If you can select the boost frequency, or if you are using a graphic equalizer or audio processing software, begin the mid-range boost at 2.5 kHz. This mid-range boost, coupled with cutting out the high- and low- range signals, provides the clarifying effect that you generally desire.

Advanced graphic equalizers offer far more range selections and control. Whatever system you have, remember that the amount for each range depends on your equipment and source file. Experiment.

Audio Normalization
The last process that you can use to create the ultimate audio source is normalization. This is normally a software process included in most audio recording and editing software. In this process, the computer calculates how much the volume of a sound file can be turned up without causing distortion. This allows you to be conservative with your recording input levels and lets your audio recording or editing software normalization function adjust the signal levels. Just remember the following:

  • Don't normalize your sound file and then perform any other form of control on your file or you'll end up with distortion.

  • Never normalize at 100 percent; it may cause compression algorithms to fail. Normalizing at 90 to 95 percent will work effectively in most cases.

The Final Step to Quality Live Audio

You can now focus on your task at hand. How do you add quality audio services to your Web site? Using the guidelines described previously, you can develop applications that provide live audio feeds to your Web site visitors or you can subscribe to one of the existing methodologies.

Luckily, developing interactive and live application sites on the Internet has become quite a bit easier. Several companies have stepped to the forefront to offer development technology to enable the Web site creator easily implemented methods for creating audio servers that provide on-demand audio services to new users, subscribers, and visitors. In addition, each of these server applications comes with multiple platform client pairs that can be downloaded from the server or from any number of similar sites on the Web.

The audio tools described below are three of the most popular client-server pairs currently available. As previously mentioned, new toolsets and development tools are appearing all the time.


Before committing to any one audio client-server system for your particular Web site, put your search engine to work by searching for "Audio" and doing some exploration on your own. This area of technology is growing quickly.

RealAudio

RealAudio is currently the most popular client-server pair development tool available. RealAudio provides a complete set of on-demand audio software products including: audio servers, audio clients, and encoders.

RealAudio's home page is at http://www.realaudio.com/ (see fig. 19.1). This home page provides download access for all RealAudio software products.

fig. 19.1 - The RealAudio home page where you can download software.

Selecting the RealAudio receiver download hypertext link opens another Web page that allows you to order the RealAudio Receiver software for several different operating systems: Windows 3.x, Windows 95/Windows NT, Mac, and a Japanese version.

Selecting the RealAudio server hypertext link opens another Web page that allows you to either order the RealAudio Server software or receive an evaluation copy that can be used to determine if the RealAudio Server system is fits your specific Web site requirements.

Selecting the RealAudio Encoder hypertext link opens another Web page that lets you order the RealAudio Encoder software for several different operating systems: Windows 3.x, Windows 95/Windows NT, and several versions for the Mac.

TrueSpeech

TrueSpeech, available from DSP Group, Inc., is a new presence in the world of on-demand audio. The TrueSpeech system is being used by a growing number of live radio sites that are cropping up on the Net. An example of TrueSpeech being used for live radio and music sources is discussed later at the San Francisco Audio Network site (refer to the following paragraph on example sites). The DSP Group, Inc.'s home page is at http://www.dspg.com/ (see fig. 19.2).

fig. 19.2 - The DSP Group, Inc.'s TrueSpeech home page.

This home page provides download access for their software products. To gain access to the download page you double-click the TrueSpeech button, which opens another Web page where you can download the TrueSpeech Audio Receiver or view the TrueSpeech video across the Net.

Double-clicking the TrueSpeech logo opens the an additional page where you can download the TrueSpeech Receiver for several versions of Windows, a couple of versions for the Mac, and a Japanese language version.

StreamWorks

StreamWorks, available from Xing Technology Corporation, is one of the fastest growing live audio programs. Part of the reason for this is undoubtedly their additional presence in the world of real-time video (refer to later in this chapter for a discussion of the real-time video sources. Xing Technology Corporation also provides a complete set of on-demand audio software products including: audio servers and audio receivers. XingTechnology Corporation's home page is at http://www.xingtech.com/ (see fig. 19.3). This page gives you download access for all of their software products. To gain access to the download page you double-click the StreamWorks logo.

fig. 19.3 - This is Xing Technology Corporation's home page.

Once you have double-clicked the StreamWorks logo, you go to a page where you can download StreamWorks Audio Server information, order the StreamWorks on-demand audio client software for any version of Windows, MAC, or UNIX OSs, or test drive a StreamWorks audio server running at Xing Technology Corporation Headquarters.

Interactive Audio Sites

Having the desire to provide live audio across the Net, the next question should be, how do you present it to your visitor? There are a number of excellent sites that you can use as an example of interactive audio sites. These sites can provide methods that you can use to set up an audio server. These sites can be used as examples of ways for you to offer various services: the ability to explore new music; obtain sound bites, obtain freeware, shareware, and commercial demos of applications; and so on.

For an example of a site that uses the RealAudio Server visit Computer Express's home page at http://www.dspg.com/allplyr.htm (see fig. 19.4).Computer Express supplies computer hardware and software and uses audio on-demand for advertising purposes, one of the many applications for audio on the Net.

fig. 19.4 - Computer Express: An Example site using RealAudio's RealAudio Server

For an example of a site that uses the DSP Group's TrueSpeech Audio Server visit the San Francisco Audio Network home page at http://www.sfaudio.net/sfan_logo.html. The San Francisco Audio Network supplies a wide variety of audio services to their subscribers including the ability to sample new audio CDs and listen to live radio.

For an example of a site that uses the Xing Technologies StreamWorks Audio Server visit Xing Technology Corporation's Test Drive page at http://www.xingtech.com/streams/streams.html. The StreamWorks Test Drive offers visitors sample uses of their Audio Server: live radio broadcasts from KWBR FM 95.3 at 16 Kbps, classical music on ISDN's 112 Kbps, and a talk radio sports program from KKAL at 10 Kbps. These are prime examples of the types of functions that on-demand audio can offer over the Net.

Xing Technologies StreamWorks Test Drive page provides the perfect segue into the next subject: live video. The Test Drive page provides a sample of the StreamWorks audio/visual server.

Video Tools, Applications and Sites

Auralview technologies are rapidly encroaching on the Internet's back country. Daily, you find that ASCII domination is being strongly challenged by Internet auralview capabilities. Live audio servers, video servers, and video conferencing systems are appearing almost daily. And while some may find it necessary to be running their Internet applications on a Sun SPARCstation with an MBONE feed, your average, run-of-the-mill, garden variety Windows NT machines certainly give them a run for their money.

Live video provides visitors to your Web site access to video information that can be transferred across the Net at speeds that are approaching real-time. The under-lying technology for live video is developing rapidly, the hardware is becoming less expensive, and both are available to the business and home user. Before deciding to supply video resources to your Web site, however, there are several items that must be defined and certain resources acquired.

The following sections outline a series of steps that you can take to insure that you develop a high-quality suite of video information and provide that to your Web site visitor.

Use High-quality Original Sources and Quality Equipment

One of the greatest factors in determining the level of video quality is using high-quality video sources. The source that you use is, of course, determined by your access to required equipment, however, here a few of the better sources of quality video:

  • Video CDs - Highest quality

  • Professional video cassette - High quality tapes

  • Video Captured AVI Files - Unknown quality

  • Home-made video cassette tapes - Lowest quality

For developing quality video from scratch, you can use:

  • Professional video cameras - Highest quality

  • Computer video cameras - High quality

  • Home video cameras - Lowest quality

  • Professional recording - Highest quality equipment and facilities

  • Home variety recording - Lowest quality equipment or facilities

High-quality equipment will produce high-quality results. This is true for every element in the recording chain, from the input source to the video capture device to the software used for capturing and editing. Remember, a little forethought into your video source file's origin can save you headaches down the road. If you intend to add commercial video services to your Web site, you should invest in professional video equipment. Don't try to obtain professional equipment from any one but a professional recording equipment dealer. Should your desire to provide video services outweigh your pocketbook, remember to get the highest-rated devices within your budget and put extra effort into acquiring quality source material.

Control the Color

Control of the color spectrum in your video source is of prime importance. The following are a few hints usually followed in the video production community:

  • When selecting still backgrounds or color highlights always use color spectrums that are easily duplicable on a SVGA color monitor. You should attempt to preview your image through NTSC/PAL/HDTV output devices.

  • Don't place saturated complementary (blue/yellow, black/white) colors next to each other since they may color-bleed.

  • Don't use highly saturated colors, especially red, as they tend to color-bleed.

  • Remember, the human eye is better at distinguishing differences in intensity than it is in distinguishing differences in hue. So use intensity as the primary variable and then hue, reserving saturation for more subtle differences.

  • Control brightness and contrast.

  • High saturation background colors should be especially avoided. Dark blue is a good background color.

Color differences are important within a single image or an animated image. Don't move the camera quickly, change from bright sunlight to shadow, or change between strikingly different subject matter. You must be sure not to change colors too quickly. This can result in a disturbing visual flickering.

Adding Textual Information

If you plan to edit your video and add textual information, make sure that your image and text are both contained within the expected screen size. In other words, don't let your text information get too close to the edge of your image. A good rule of thumb is don't place text closer than 1/10 of the overall screen size to any screen edge.

If you plan on changing the text displayed on the screen, allow for adequate delay time. This delay should be proportional to the text's complexity. Two to three seconds is fine for a word or two or a short sentence. Longer times are appropriate for more text; however, dense text should be avoided. Time yourself reading the text displayed and then add a few extra seconds. Also, text should not exceed twenty characters per line and you should use large font sizes (greater than 30 pt) for titles.

Applying Shapes and Frames

If you intend to add shapes such as circles, squares, frames, or other non-linear shapes, don't use single pixel-wide lines. If you do, you most likely will find that vertical lines lose their color and horizontal lines flicker. Both result in an annoying video. Most video editors allow you to set line width sizes; choose a line width of at least two pixels.

Motion Video, Animation, and Other Moving Bodies

Animated subjects are worthy of great detailed explanations. It is not within the scope of this book to approach that depth of discussion; however, a few hints certainly can't hurt.

If you plan on using a revolving or moving object, time your motion correctly. Rotating objects should complete a revolution within three to eight seconds, depending on the complexity of the rotating shape. You should test this on yourself and colleagues. If you make the motion too slow, the end result may be very boring; make it too fast and the motion won't seem realistic or might difficult for the eye to follow. For moving objects, be sure that the speed of the motion is not too slow to put the viewer to sleep and is fast enough to hold the viewer's interest. Don't make your viewers' heads spin with excessive motion. Effective frame rate can be slowed down to achieve different visual effects. If you play a video at five to six frames per second (fps), the end result is a "slow motion" look. Increasing the speed to nine to ten fps results in a "jittery" video. Full motion for the human eye is 30 fps. Control your effects carefully because their results on your video can be immense.

Miscellaneous

The image aspect ratio of your finished video is also an important factor to remember. If you have ever tried to watch a movie that was shot in VistaVision on your standard television, you have run into the problem of improper aspect ration. Be sure that your final video image conforms to the aspect ratio of the viewing device; the SVGA monitor your visitors are using.


The correct aspect ratios for NTSC, PAL, and HDTV are 4:3, 4:3, and 16:9, respectively. Computer displays, as a rule, do not conform to these ratios. As a result, video images with these aspect ratios appear distorted when viewed.

When recording your video masters, or when selecting masters that have been pre-recorded, choose the highest resolution video format available. Any and all subsequent videos can then be dubbed from this master.


When comparing the resolution of various video source standards, use the following guide. Resolution increases from left to right in the following formats: VHS -> SVHS -> Hi8 -> BetaCam SP -> D2 Digital

Video Transmission Bandwidth

Since you have already determined the transmission bandwidth of our video server, you need not concern yourself with the concept of fps transfer rates. Your only concern at this time should be with compression.

Compress or Don't Compress: Your Two Options

Taking a quick trip around the Internet and the World Wide Web in search of live video results in some startling revelations. If you attempt to run uncompressed video in a full motion mode, using a 14.4 Kbps modem, the time such running takes is incredibly long. This is certainly not full motion video. choosing to use one of the available video servers or video conferencing servers that are available has to be a determining factor in both your equipment decisions (that is, going to an ISDN modem and supporting analog modems) and in your choice of Web site server. These are choices that you have to make based on need, funds, available equipment, and target audience.

A video codec is the device that physically performs the act compressing and decompressing video images for transmission across a LAN or WAN. The current freeware CU-SeeMe application, offered by Cornell University, supports a codec that produces grayscale images compatible the existing software

Adding Quality Live Video to Your Web Site

With that little bit of video background behind you, you can now focus on your task at hand. How do you add quality video services to your Web site? Using the previously described guidelines, you can develop applications that provide live video feeds to your Web site visitors, or you can subscribe to one of the existing methodologies that are available today.

Just as in advanced audio techniques, the are also several companies that have stepped up to offer development technology to enable the Web site creator to add either a video server or video conferencing services to new users, subscribers, and visitors. Again, each of these video applications comes with multiple platform receiver pairs that can be downloaded from your Web site or from any number of similar sites on the Web.

The video tools described in the following sections are several of the more prominent Windows NT video applications currently available. Each of these applications serve as video teleconferencing servers. If you think about it, the step between a pure video service, such as the one offered by InterneTV (found at http://www.crs4.it/~france/TV/ and where their viewers are allowed to watch Italian television with video and sound), to offer fully interactive video conferencing is a small one.


Before committing to any one video system, put your search engine (refer to chapter 15, "Search Engines and Annotation Systems," for information on search engines) to work by looking for "Live Video" across the Net and then doing some exploration on your own.

FreeVue

FreeVue provides complete video teleconferencing products. The FreeVue home page is at http://www.freevue.com/ (see fig. 19.5)and provides download access for their video conferencing software.

fig. 19.5 - This is the FreeVue home page.

Selecting the FreeVue software hypertext link opens another Web page where you can download the FreeVue teleconferencing software for Windows NT.

StreamWorks

StreamWorks, available from Xing Technology Corporation, supplies several products for the world of Internet real-time video services. They provide video conferencing software and MPEG players. The Xing Technology Corporation home page is at http://www.xingtech.com/. This page provides download access for all of their software products. To gain access to the download page you double-click the StreamWorks logo.

Double-clicking the Xing MPEG logo opens another Web page where you can download StreamWorks' MPEG player. Double-clicking the StreamWorks logo launches an additional selection screen where you can download StreamWorks' Video Conferencing software or test drive an example of the StreamWorks server that is running at Xing Technology Corporation headquarters.

CineVideo/Direct

CineVideo/Direct, a product of CineCom, is another popular video conferencing software products for the world of Internet real-time video services. The CineCom home page is at http://www.cinecom.com/CineCom/cinvdrct.html (see fig. 19.6). This page provides download access for CineVideo/Direct, and a list of current connection sites, and a ListServer for easy access to these sites. They also provide a history of the product for those interested. Selecting the CineVideo/Direct Software hypertext link downloads the CineVideo//Direct software (currently available for Windows NT).

fig. 19.6 - This is CineCom's home page where you can download CineVideo/Direct.

Additional technical information about CineVideo/Direct is available at http://www.cinecom.com/CineCom/directtech.html.

CU-SeeMe

One of the more definitive video conferencing packages available is CU-SeeMe. This software package is a product of research being conducted at Cornell University and is available via anonymous FTP from their site at ftp://gated.cornell.edu/pub/video.


There are no CU-SeeMe players for UNIX currently, but there are reflectors. This section is included anyway to give you general knowledge of the technology.

An commercial variation of CU-SeeMe, Enhanced CU-SeeMe, is available from White Pine Software, Inc. at http://goliath.wpine.com/cudemown.htm. Here, users can download a 30-day demo version of the Enhanced CU-SeeMe video conferencing software. They are first required to obtain a Registered DEMO Serial Number. The form for this registration can be found at http://goliath.wpine.com/cuserial.htm.


White Pine Software, Inc. has been selected by Cornell Research Foundation as master licensee of Cornell's CU-SeeMe desktop video conferencing technology. White Pine's charter is to create low-cost, commercially enhanced and supported versions of CU-SeeMe and make it available to Internet users worldwide, bringing the advent of everyday video telecommunications one step closer.


White Pine Software, Inc. can be reached at http://www.cu-seeme.com.

CU-SeeMe provides Windows NT users with person-to person or group video teleconferencing. To provide the computing horsepower and equipment muscle necessary for video conferencing, CU-SeeMe connects each user in a group to a reflector site. A reflector site is usually a UNIX-based computer powerhouse, such as a Sun SPARCstation with an MBONE feed, that facilitates multi-participant conferencing.


If a user wants to be placed on the CU-SeeMe mailing list, he/she need only send an e-mail message with subscribe cu-seeme-l and his/her name to listserv@cornell.edu.

After installing the CU-SeeMe software and performing some relatively trivial configuration, the user can open a receive or send/receive connection to the numerical address of another participant or the reflector site. Once connected, a split screen appears that contains the live video of each person connected to the reflector. A user can never tell exactly what he might find when connecting to the reflectors. Connect and he might find himself in the middle of a multi-window conference - or staring at a test pattern or empty office.

Available Reflector Sites
The following is a list of the reflectors that are available for public use:

  • www.cu-seeme.com (192.233.34.5)

  • goliath.wpine.com (192.233.34.20)

  • reflector.cit.cornell.edu (132.236.91.204)

  • isis.dccs.upenn.edu (130.91.72.36)

  • hilda.ncsc.org (128.109.178.103)

  • NASA (139.88.27.43)

Hostname
A computer may need a hostname to talk on CU-SeeMe. If so, and the user doesn't already have a hostname, she must contact her network administrator. One quick way to provide a hostname is to make an entry into the hosts file, which is in the directory that contains the user's Windows Sockets stack.

A host file entry uses the following syntax:

<your IP address> <name for your PC>

If, for example, the user has selected a hostname of VIDconServer and his IP address is 228.232.6.4, the host's file entry is 

228.232.6.4 VIDconServer

Virtual Worlds: Tools, Applications, and Sites

The current state-of-the-art of virtual reality (VR) technology for the Internet community is Virtual Reality Modeling Language (VRML). This language is the basis of almost all VR participation on the Net, today. The following paragraphs discuss both VRML and other variations on this theme and an VR site, and a site where you can obtain one of several VRML Browser's that are currently available.

While most VRML experiences are not truly "live" - it's coming quickly.

VRML (Virtual Reality Modeling Language)

VRML stands for Virtual Reality Modeling Language. It is a file format describing the geometry of network-aware 3D objects. A VRML file might describe a house, inside which one could find a door which is a hyperlink to another VRML file containing a library, in which one might find a book which is a hyperlink to an htmL page. Version "1.0" of the file format simply described the geometry of objects; VRML 2.0 will describe geometry with hooks for "behaviors" to be attached, using any number of programming languages, such as Java. The 2.0 specification is being finalized at the time of this writing, and an early implementation can be found in the "Live3D" plug-in for Netscape.

VRML has a support Web site, called the VRML Technical Forum, that is located at http://vrml.wired.com/vrml.tech/. This support site provides downloadable copies of the VRML Version 1.0 Specification and the VRML Programming Library Version 1.0 beta 1. These sites are also very helpful: http://www.sdsc.edu/vrml/ and http://vag.vrml.org/.


To properly server VRML files off your site, you must map the file name extension to the right MIME type. For VRML 1.0 files, it is x-world/x-vrml. So, it should either be listed in your mime.types file, or added using an AddType directive in a configuration file.

VRML Browsers

There are several VRML browsers. The best listing of available browsers is at http://www.sdsc.edu/SDSC/Partners/vrml/software/browsers.html

Live VR Worlds

There are a number of interactive world applications in development today. These worlds combine a 3-D experience with real-time person-to-person interaction. This section introduces you to three of the more advanced systems with the caveat that these sites are more than just Web site additions. These new worlds are a new technology on a par with Web technology; they represent the next generation of Internet technology.

Worlds chat

Worlds chat is the revolutionary 3-D, virtual chat, and entertainment environment. Worlds chat allows users from all over cyberspace to meet and interact in a virtual space station. The chatting is done via keyboard, and the users create Avatars (digital actors) to represent themselves. Careful, it's addicting! To check it out, go to http://www.worlds.net/products/wchat/.

AlphaWorld

AlphaWorld is perhaps the first true online society. You can stake your claim and build your own site in this multiuser VR land. That's right, the users actually build the world! As of this writing, AlphaWorld is very much in beta, and very amazing. AlphaWorld is a creation of the same company as Worlds chat. You will probably notice the visual similarities. Go to http://www.worlds.net/products/alphaworld/.

Traveler

OnLive! Technologies has developed software that allows real-time multi-point voice chat within 3-D virtual environments. What's that mean to you? It means you can talk - using your voice, not your fingers - to groups of people from all over the Internet. This is an interesting twist to the chat scenario. The avatars have facial expressions and your avatar's mouth moves when you speak. This is certainly one of the most entertaining Internet technologies you will see anytime soon. Go to http://www.onlive.com.

The Not-Too-Distant Future: Auralview, W3Vision, and the WebStage

The not-to-distant future offers many possibilities. Possibilities that are Works In Progress at this moment. As a finale to our discussion of Interactive and Live Applications, I would like to dance a bit in the dream world of the future. Here, I would like to define some of the future applications and concepts that I have introduced during our discussion (and if you haven't looked these terms up in the glossary yet, shame on you!).

Auralview

The world of auralview is only slightly different from where we are today. Auralview is really an extension of the concepts of video conferencing. In this future application area of Internet interaction, we not only have true full motion video, either live, 3-D animated, or both, we also have 3-D sound and possibly even surround sound. The applications are endless: from Internet telephones, to interactive entertainment services; from distributed, industrial training 'films', to K-12 educational video shows. This is a world of interactive classroom-less Colleges. A world in which talking to your computer is no longer a sign of impending visits to the little rubber rooms at some of our posh Sanitariums.

W3Vision

The World of World Wide Web [W3] Vision is a world of endless Video and sound access from strategic places around the world, and out of this world. A place where, by simply 'dialing' in a requested location we can explore the ocean seas, floors, canyon, and volcanoes. Where we can observe the Earth as it spins on its axis, in real time and from any one of several hundreds or thousands of views.

Where a trip to the surface of the Moon, Mars, or Venus, need not take leaving the planet, but could be enjoyed in the comfort of our living rooms.

WebStage

An finally, the inter-galactic WebStage. The WebStage is a place where you can truly be a part of the action. Where participation of world events, sporting events, plays, game shows, and training seminars takes place at your office desk, or in front of the home Multi-purpose AuralView Interface System [MAVIS]. This is our Internet future - a future you, as Web site developers, owners, and maintenance personnel, will help to define, refine, and direct.

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