The Florida SunFlash Multimedia: Introduction (1 of 6) SunFLASH Vol 40 #25 April 1992 ---------------------------------------------------------------------------- This set of 6 articles explains the tecnologies of Multimedia technology. -johnj ---------------------------------------------------------------------------- 1. Introduction to Multimedia 2. Sun's Multimedia Direction 3. Key Multimedia Concepts 4. Audio 5. Video 6. ISDN ---------------------------------------------------------------------------- 1 Introduction to Multimedia Multimedia technology will ultimately take the disparate technologies of the computer, the telephone, the fax machine, the CD player, and the video camera and combine them into one powerful communication center. Technologies that were once analog - video, audio, telephony - are now digital. The power of multimedia is the integration of these digital technologies. At some point in the future, Sun Workstations" will be connected via Integrated Services Digital Network (ISDN) phone lines to workstations around the world. The implementation of ISDN will make possible an international phone system that will serve as a global network. If as the saying goes, the "network is the computer", then the "computer" is about to become very large. This will geometrically expand the number of ways that we can exchange information. We'll exchange electronic mail with people on other networks, in other companies, in other countries. We'll fax information to them directly from our workstations. We'll be able to set up a video-conference from our workstations with people on the other side of the world who aren't even on the same network. They'll be able to see us and hear us, and we'll be able to see and hear them at the same time. We'll develop documents with audio and video components that we can then send anywhere. There is even the future possibility that we'll be able to speak into our computers and mail a translated audio message electronically to a recipient in another country speaking another language! This booklet describes some key concepts for multimedia. It talks about Sun's multimedia directions, and describes some of the more technical aspects of audio, video, and ISDN technologies. Before looking at multimedia in more detail, let's take a look at how multimedia technology can benefit a company's business. The following scenario will become more and more common in the months and years ahead. Let's say that you run a major credit card company that employs thousands of people, and that you have recently succeeded in getting your company to adopt multimedia technology. What kinds of changes might you see that tell you that your efforts have paid off? o Service time per customer reduced, and an additional increase in customer satisfaction When a customer calls in, a window displays on the service representative's screen with complete information about the customer: records of the last series of transactions, images of credit card slips, and a variety of other pertinent information. A service representative can raise a customer's credit limit by creating a document on-line with the customer's request and credit information, and forwarding it over the network to a credit agent in another city. The agent can send the customer a fax of the request. Based on the information in the database, the service representative can propose other services to the customer. For instance, for a customer that travels often the agent can discuss new travel discounts. o A decrease in travel time and expenses and an increase in the level of communication Now you as CEO can hold meetings with your executives by simply setting up a videoconference on your workstation so you can all see and hear each other. You can discuss current issues, examine and mark up documents together, and even share a whiteboard - all on your own workstations. Your company's high-level executives also like the way that multimedia keeps them in touch with each other when they do travel. Via phone lines, they can check back with the main office to receive voice or electronic mail messages. They can even pull important information from their workstations and have it faxed to them or read to them over the phone, using a text-to-speech application. o A decrease in the amount of time required to train new employees, less money spent on training efforts, and an increase in customer satisfaction A series of modular multimedia presentations were developed in-house incorporating text, still images, full-motion video, graphics, and audio. New employees can now learn their jobs interactively at their workstations by viewing presentations specific to their work. Because the modules are developed in-house, they can also be easily updated to accommodate the latest information. The above scenarios might seem like a slice of life from the next century, but these scenarios are really a lot closer than that. To learn more about multimedia and the plans Sun has for incorporating multimedia into its products, read on!
The Florida SunFlash Multimedia: Sun's Directions (2 of 6) SunFLASH Vol 40 #26 April 1992 ---------------------------------------------------------------------------- 2 Sun's Multimedia Direction Sun's direction in multimedia centers around the concept of collaborative multimedia - multimedia applied to corporate communication enabling increased group productivity and creativity, faster development of higher quality products, more efficient corporate processes, better customer service. In short Sun intends to provide a competitive advantage by empowering teams with powerful access to and manipulation of information. Collaborative Multimedia Sun defines collaborative multimedia as the combination of multimedia with desktop systems and networking to enable powerful communication systems for groups of people working in teams. Multimedia Multimedia enables people to communicate using integrated media: audio, video, text, graphics, fax, and telephony. The benefit is more powerful communication. The combination of several media often provides richer, more effective communication of information or ideas than a single media such as traditional text-based communication can accomplish. The Desktop The desktop workstation is the new communication center - the individual's connection to the enterprise. Through the desktop the individual can connect with other individuals and with information sources such as documents and databases. The desktop is also the focus for the integration of critical office automation resources such as fax, telephone, answering machine, address file, and so on. It integrates these resources, both into the workstation and with each other. Finally, the multimedia desktop will provide built-in standard multimedia capabilities such as audio, video, telephony and fax. Multimedia functionality will be built-in, both in hardware and in software development platforms as well as standard desktop software. Developers can count on a certain level of multimedia functionality on every desktop. The Network Powerful networking capabilities provide access to people and information across not only the enterprise, but cross-platform and globally as well. People and information must also be accessible when you are not at your desk through portable computing and remote access. For instance, you could call your workstation from a public phone and have important information read to you. Powerful Platform for Powerful Communication The networked multimedia desktop is a prerequisite for collaborative multimedia; powerful communication depends on a powerful platform. This platform must be multimedia-ready, with bundled multimedia technology supported by a multimedia development environment and adherence to standards. Connectivity (networking), speed (workstation performance), multi- tasking, and a client/server architecture are all necessary to enable this level of communication power. Empowering Teams with Information Collaborative multimedia enables new levels of multimedia solutions for individuals, workgroups and corporations as a whole. Personal multimedia solutions provide new ways of delivering information to individuals. Group multimedia involves new ways of working together. Corporate multimedia enables whole new ways of doing business. The more powerful communication that collaborative multimedia enables can provide a real competitive advantage. Collaborative multimedia is much more than just presentations and entertainment: it enables faster development of higher quality products, better customer service, more efficient corporate processes, and increased group productivity and creativity. See the Multimedia on Sun Workstations brochure for examples of how Sun customers are benefitting from multimedia today. Personal Multimedia In the 1990s, information must be accessible in many forms. Personal multimedia involves new ways to deliver information to the individual. Typically the communication is one way - experts create/author the materials, and the individuals view (play back) the materials. Prepared materials, such as presentations or multimedia documents, may be viewed from media (CD- ROM, video disc, VCR) or from on-line files. Examples include employee training, sales presentations, or customer service kiosks. Network access means that the information can be distributed over the network and located away from the individual user. Group Multimedia Group multimedia enables real-time, interactive collaboration among members of a project team, customer service group or other work group. Communication is two-way: team members are both authors and viewers of the shared materials. Functionality includes screen-sharing so team members can view each other's work, shared whiteboard capability enabling interactive mark up of documents, and video conferencing for real-time interactive exchange. Everything you need during your conference is already available from your workstation, ready to be shared. Typical uses of group multimedia would be for collaborative business analysis and decision making, or for concurrent engineering. Corporate Multimedia Corporate multimedia centers around the impact of multimedia on applications that are critical to the nature of the corporation's products or services. Examples are o Collaborative medical diagnosis and treatment in a healthcare facility o Customer service, such as order processing in a manufacturing company o Intercompany cooperation, such as insurance claims settlement Typically these types of applications are developed in-house by MIS departments, or by vertical independent software vendors or system integrators. They are applications that directly affect the bottom line of the business. Sun's 3-Point Multimedia Strategy Sun's multimedia strategy involves: o Delivering multimedia-ready workstations o Providing an open development environment o Forming key strategic partnerships The Multimedia-Ready Workstation Sun workstations are multimedia-ready today. SPARCstations have included voice-quality audio since their introduction in 1989. They also support large screen displays, high-resolution color graphics, and a CD-ROM interface. The multitasking capability of the operating system and extensive networking support are fundamental enabling technologies required for true collaborative multimedia. The OpenWindows V3 multimedia mail tool and Calendar Manager are the first DeskSet applications to begin to address collaborative work and multimedia communications. As time goes by the level of multimedia support bundled in Sun Workstations will increase. Over 100 third-party solutions related to multimedia are available today. These encompass products in the areas of: o Multimedia documents and multimedia mail o Image manipulation and animation o Video hardware and software o Audio and speech recognition o Multimedia presentations and hypermedia o ISDN and fax These third-party products make Sun fully equipped for multimedia. See the Multimedia Portfolio for a complete listing of Sun and third-party products that support multimedia. An Open Development Environment The Sun multimedia platform will provide a unified multimedia programming interface for developers. It will be based on industry standards, and will be cross-platform. Sun participates in a number of key standards organizations: o Interactive Multimedia Association (IMA), which deals with cross-platform multimedia standards o International Standards Organization (ISO) and International Telecommunications Standards Organization (CCITT) which deal with video compression o National ISDN User's Forum (NIU) o CCITT also deals with fax o SPARC International (SPARC compliance definition) o UNIX" International (multimedia team) The standards that Sun is tracking for cross-platform interoperability are in the areas of: o Video o Video and audio compression o Communications o Fax o CD-ROM o Graphics and imaging o File formats o Device control Key Strategic Partnerships Partnerships are critical to the development of Sun's multimedia strategy. Sun is undertaking several types of partnerships: o Technology partnerships. These focus on joint platform development, including joint applications programming interface (API) development, cross-platform development and standards efforts. o Software and hardware developers. These focus on complete solutions including applications software. The goal is to move beyond multimedia- ready to actual multimedia solutions o Customers. The focus is on requirements identification and development of multimedia solutions. Customers provide feedback on the platform work, proof-of-concept for significant solutions and success stories. Sun's Differentiation Sun's collaborative multimedia strategy provides a powerful competitive advantage for corporations. o Multimedia-ready workstations from Sun provide standard multimedia capabilities that will track emerging industry and de facto standards. In addition, an open multimedia development environment will facilitate the development of key multimedia solutions. o Sun's speed, connectivity, multi-tasking capabilities, and client-server architecture provide the infrastructure to support collaborative multimedia. o Sun's multimedia-ready workstations enable corporate-wide solutions that can provide a competitive advantage and positively affect the bottom line.
The Florida SunFlash Multimedia: Key Concepts (3 of 6) SunFLASH Vol 40 #27 April 1992 ---------------------------------------------------------------------------- 3 Key Multimedia Concepts Before reading about the more technical aspects of multimedia, you should be familiar with some of the key concepts that apply to multimedia technology. --------------------------------------------------------------------------- Key Processes --------------------------------------------------------------------------- Authoring Authoring is the process of using multimedia applications to create multimedia materials for others to view. Multimedia authoring utilizes a wide variety of tools, from the more familiar text editor or desktop publishing application, to tools for capturing and manipulating video images or editing audio files. Authors might include specialized creators of training, sales, or corporate applications such as insurance claims processing. Or, they might be creators of everyday business communications like voice-annotated email. Over time, everyone involved in business communications will probably have some level of multimedia authoring capability. Playback Playback is the process of viewing multimedia materials created by an author. Playback can include a range of activities, from viewing a single video clip to participating in a series of interactive multimedia training modules. Some playback applications (for example many training and presentation applications) are sold separately from their authoring applications. However, many developers are selling authoring and playback capabilities in a single product. Collaboration Collaboration involves two or more people working together in real-time, or in a "store-and-forward" mode (defined in the next section). Applications in development will enable a group of people to collaborate in real-time over the network using shared screens, shared whiteboards, and video conferencing. Collaboration can range from two people reviewing a slide set on-line to a conference of doctors at different locations sharing patient files and discussing treatment options. Editing Editing is the familiar process of changing the content of files to achieve more effective communication by cutting, pasting, cropping, resizing, or copying. Multimedia editing can be done on all types of media: voice annotations, music, still images, motion video, graphics and text. Tools for editing vary from simple tools for email voice annotations to more sophisticated tools for video manipulation. --------------------------------------------------------------------------- Key Concepts --------------------------------------------------------------------------- Real-Time Operating in real-time means that there is little time delay in the communication of information. You make a change to a screen display, and your colleagues at different workstations see the change almost immediately. This is in contrast to the concept of "store-and-forward". Store-and-Forward The concept of store-and-forward means a time delay between the creation and receipt of multimedia materials. This is the process that most people currently use. It does not accommodate live interaction between people. The information is created at one point in time, and received at another. An example of this is today's electronic mail. Synchronization Synchronization is very precise real-time processing, down to the milli-second. Some forms of multimedia, such as audio and video, are time-critical. Time delays that might not be noticeable in text or graphics delivery are unacceptable for audio and video. Workstations and networks must be capable of transmitting this kind of data in a synchronized manner. Where audio and video are combined, they must be time-stamped so that they can both play back at the same time. One-way Communication One-way communication goes from an author to a playback user, but not the other way around. Examples of one-way communication include training and documentation materials, and presentations. The material is authored specifically for playback by the end user and not for a collaborative work effort. One-way communication materials remain unchanged until the master is updated by the author. Multi-way Communication Multi-way communication goes between two people, or between groups of people in all directions. Multi-way communication can be in real-time, or in store-and-forward mode. Examples of multi-way communication include a video conference, where one individual is giving a presentation to a group of people who listen and ask questions from their workstations; and group conferencing, where several people collaborate, supported by audio, video, and graphics on their workstation screens. Compound Documents A compound document is one that enables incorporation of different kinds of media - audio, video, images, text, and graphics. --------------------------------------------------------------------------- Key Applications --------------------------------------------------------------------------- Videoconferencing Videoconferencing is communication with others using video and audio applications to see and hear each other. Audio can be provided through specialized videoconferencing equipment, through the telephone, or through the computer. Videoconferencing has traditionally been done with dedicated equipment. The use of computers for conferencing is very recent. Synchronized, real-time audio and video is required. Shared Screens Shared screen applications enable two or more workstations to display the same screen simultaneously. For example, two users sharing a screen can work on the same spreadsheet. Changes made by one user can be seen by the other as they are made. Shared screens can be implemented in two ways. One way enables people to view each other's screen while one person makes changes. The other way enables people to run the same application on both screens so that both users can make changes simultaneously. Shared Whiteboards Shared whiteboards enable you to "mark-up" a screen using a mouse or stylus input device and have the results show on other screens. The concept is similar to a traditional whiteboard mark-up process where everyone has a different color marking pen to circle, write, or cross out items. The background board can be a window from the workstation such as a spreadsheet, image, or blank canvas, or it can be the entire workstation screen. The shared whiteboard can be used for either real-time or store-and-forward collaboration. In the store- and-forward scenario, the mark-ups can be implemented in a time-delayed fashion so everyone can follow the entire step-by-step process. Software-only Video Playback Video software playback displays a stream of video without any specialized chips or boards. The playback is done through a software application. The video is usually compressed to minimize the storage space required. Hypermedia Hypermedia is a type of authoring and playback software through which you can access multiple layers of multimedia information related to a specific topic. The information can be in the form of text, graphics, images, audio, or video. For example, suppose you received a hypermedia document about the Sun file system. You could click on a hotspot (such as the words file system) and then read a description. You could then click an icon to see an illustration of a file structure, and then click the file icon to see and hear more information in a video explaining the file system. Runtime A runtime environment is the software that plays back multimedia materials. The runtime material is created by the author. Examples of runtime applications are presentations and training, where the material cannot be edited but only viewed. The runtime software could be a slide show viewer, a software-only video playback application, or a hypermedia runtime document. Device Control Device control enables you to control different media devices over the network through software. The media devices include VCRs, laser disc players, video cameras, CD players, and so on. Control capabilities are available on the workstation through a graphical user interface. They are similar to the controls on the device itself, such as play, record, reverse, eject, and fast forward. Device control is important because it enables you to control video and audio remotely - without requiring physical access. Telephony Telephony refers to the integration of the telephone into the workstation. For instance, making or forwarding a call will be as easy as pointing to an address book entry. Caller identification (if available from the telephone company) could be used to automatically start an application or bring up a database file. Voicemail and incoming faxes can be integrated with email. Users can have all the features of today's telephones accessible through their workstations, plus the added benefits provided by integrating the telephone with other desktop functions. Titles When an author sells what he or she has created, it is called a title. For instance, the various encyclopedias, dictionaries, musical works, and games available on CD are all "titles". Someone authors the material, and sells it to users who can play it back but not change the content.
---------------------------------------------------------------------------- The Florida SunFlash Multimedia: Audio (4 of 6) SunFLASH Vol 40 #28 April 1992 ---------------------------------------------------------------------------- 4 Audio Audio plays an important role in multimedia applications. When a service representative adds a voice note to a credit record, when executives hold a video conference, when travelers listen to voice mail or have their email read to them over the phone, or when new employees complete training modules, they all use desktop audio. Audio Applications Audio can be used in many applications, including voice annotation, voice conferencing, voice mail, training and presentations, text-to-speech, and speech recognition. The following paragraphs describe some of these applications. Voice Annotation A voice annotation application enables audio comments to be added to documents, data base records, and so on. These applications can be built using fairly simple record and playback capabilities. For example, someone records a voice comment and attaches it to a certain spot in a document. The document then displays an indicator, showing that an audio note is attached. While viewing the document, the reader can select the indicator to play back the audio recording. Voice annotation applications may also provide some simple audio editing capabilities for message creation. Voice Conferencing Voice conferences enable people to speak to each other in real-time over the network. Voice conferencing is an alternative to video conferencing since both parties do not always have to see each other. Often, voice conferencing would be used in a collaborative environment, where two people can sit at their workstations, look at the same document at the same time, and make verbal comments about it. Voice Mail Voice mail provides a way to send and receive voice-quality audio recordings in a multimedia email message. Audio messages can be recorded, sent as attachments to a multimedia email message, and played back by the recipient. With the integration of telephony into the desktop, messages could be recorded automatically by a telephone-answering application, and forwarded as email to the telephone owner. Training and Presentations Audio can be very effective in training applications. It can provide a soundtrack for video segments, or for illustrations of any form. It can also provide help and feedback to the student with a more personal feel, and without interrupting the student's focus. Audio can also provide richer, more interesting, and more effective presentations. Audio in combination with other multimedia technologies enables authors to create presentations of a quality that meet the expectations of today's consumers. Text-to-Speech Text-to-speech technology enables information stored as text to be converted to speech - effectively to be read aloud. Applications can use text-to-speech to provide verbal help, or to read your calendar, address file information, email message or other information. When integrated with telephony capabilities, text-to-speech technology can provide remote access to information. For example, you could telephone your computer and have it read your mail or appointments. This technology can also provide spoken desktop messages, such as a reminder of a pending appointment, without imposing a pop-up window into the middle of your current work. These desktop alerts could include announcing an incoming email message or, with telephone integration, an incoming phone call. They can also provide spoken status messages or warnings from the system. Speech Recognition Speech recognition enables you to speak to your computer through a microphone or telephone. The workstation translates the voice input into text that the system can understand. This technology enables the use of voice as an additional input channel to supplement the keyboard and mouse. For example, radiologists save valuable time by dictating their x-ray reports into the computer for immediate viewing. They can be edited by voice or by keyboard. You could also give commands to open and close windows or start applications without moving away from your current work. With telephony integration, speech recognition would enable you to give commands to your workstation verbally over the telephone, for example, "Read the headers of any mail messages from William Tell." Speech recognition technology in the near future will be limited in the size of its vocabulary, and will typically require you to train your system to your own voice. Eventually, these restrictions should disappear. Key Audio Concepts Multimedia audio applications depend on the interaction of a number of variables such as the type of audio and how it can be digitized, edited, stored, and played back. The following paragraphs describe some of these key concepts. Types of Audio Workstations generally support two types of audio input and output: o Music quality audio (often called CD-quality audio or 16-bit audio) o Voice quality audio (also known as telephone quality or 8-bit audio) MIDI data, which specifies music, is also often included in the audio category. CD-quality Audio CD-quality audio requires both higher sample rates and greater sampling precision (more bits of data), thus making greater storage and processing demands on the workstation. Today, applications requiring CD-quality audio are found primarily in the music industry. The use of CD-quality audio for business training and presentations, while currently limited, is expected to expand considerably throughout the corporate marketplace. CD-quality audio is typically input from a CD player or DAT (Digital Audio Tape) player, and is output through a high-quality speaker. Voice-quality Audio Voice-quality audio can reproduce the comparatively limited dynamic range of the human voice. Voice-quality audio is standard on every Sun desktop workstation, enabling multimedia applications ranging from electronic voice mail to voice annotation of documents to voice control of your workstation. Voice-quality audio is commonly input from a microphone or over a telephone, and can be output through a speaker built into or attached to the workstation, or using a telephone handset or speaker phone. MIDI MIDI (Musical Instrument Digital Interface) is a note-oriented control language for specifying music. MIDI data consists of codes specifying notes and timing. These codes can be generated by or output to MIDI-compatible devices such as keyboards or synthesizers. MIDI applications are generally found in the computer music industry, used for studio control and audio production. Audio Editing and Manipulation You can perform various operations to audio data stored in a file in addition to playing it back. Probably the most common operation is to edit the audio data. Programs that do audio editing typically generate a display of the waveform representing the data, and then enable you to specify sections of data to cut out or relocate. Editing can be used to isolate segments of interest (for example, to create a "sound bite"), or remove leading or trailing noise, silence, or pauses. Another common operation is the mixing of sound files, for example to combine a voice overlay on top of a music background for a training application or in a presentation. Audio Playback Playing back stored audio data requires regenerating the analog audio signal from the digital data. This is done by a digital to analog converter or DAC. The analog signal can then be output to a speaker built into or attached to your workstation, to the speaker in a telephone handset, or to a speakerphone. Capturing and Digitizing Audio Sound, or audio, is analog data. To store, manipulate, and enhance it using a computer, it must be digitized - converted to a computer-readable format. Audio starts as a complex analog waveform coming from some form of input device, such as a microphone, telephone handset, or CD player connected to your workstation. An audio signal is characterized by its bandwidth, the highest frequency in cycles per second or hertz (Hz) that can be represented in the waveform. Digitizing this signal involves two processes, sampling and quantization. These functions are generally performed by a chip known as an analog-to-digital converter, or ADC. Today the ADC and its counterpart, the DAC, are sometimes combined into a single chip called a Coder-Decoder or CODEC. The quality of audio a workstation supports is primarily determined by the capabilities of the ADC and DAC components. Audio Data Storage Once the audio input stream has been captured and digitized, it can be stored in a data file for later playback or for editing or other processing. Even voice- quality audio is data intensive; one minute of voice-quality audio on a SPARCstation takes almost half a megabyte of storage space. One minute of uncompressed CD-quality audio (16-bit 44.1 Khz stereo) would require close to 10 Mbytes of storage space. Besides the raw data, you also need to store information about the data, such as its sampling rate, the number of bits per sample, and the encoding algorithm used. This information is necessary in order to be able to reproduce the original signal. Thus, audio data is commonly stored in files with a special format that includes this data, often in some sort of header structure. This often requires special routines to write the data to these files and to read it back properly. Multi-Channel Audio Many workstations, such as today's SPARCstation family, support one channel of audio, or monaural sound. Multiple channels are also possible. Supporting two channels (stereo) requires two input and two output ports, independent ADC/DAC components for each data stream (or components designed to handle two channels), and a data representation format for the storage of multiple channels of data. Challenges There are still some challenging issues to tackle before audio will become commonplace on the desktop. One of the most significant is the development of more effective ways to handle the volume of data that audio involves. Development of compression algorithms to minimize storage space and network bandwidth to allow transmission across computer networks is an area for further research. Ongoing research in the area of text-to-speech and speech recognition is another challenge. More human-sounding speech generation, and more flexible and accurate speech recognition are important goals for the future.
The Florida SunFlash Multimedia: Video (5 of 6) SunFLASH Vol 40 #29 April 1992 ---------------------------------------------------------------------------- 5 Video Desktop, full-motion digital video brings a new level of collaboration and communication to corporations. Just as visual communication, through pictures, can provide vastly more information than words alone, moving pictures can offer more and in some cases better, information than still images. Video Applications Full-motion digital video means a continuous sequence of video images integrated in the workstation. The ability to capture, archive, edit, display, and transmit digital, full-motion video provides both new and better internal corporate communication, and innovative, attention-getting, external communication with customers. Collaboration The shared workstation video-window will redefine workgroup computing. The networked video-capable workstation will provide a new level of collaboration among working groups. The current workgroup collaborates by sharing email and documents. The workgroup of the 1990's will also share images, video and audio. Multimedia Mail Just as email can include images and sound, it can also include a sequence of images. A mail application could enable users to place, and possibly edit, digitized video in a standard email message. The video might have been captured from a television broadcast, an in-house talk or trade show demonstration, or synthetic images generated on the workstation. Video Conferencing Video conferencing using special equipment not associated with the workstation has become both commonplace and a necessity for corporate communication. Current implementations are expensive (both for equipment and dedicated high-speed phone links) and typically available in very few locations within a corporation. Video conferencing on the workstation will fundamentally change the role it plays in corporate communications. Individual workstations, with video capture capability and inexpensive cameras, will capture, compress and transmit video (and audio) over local networks or ISDN lines to one or many workstations. You will be able to start up this application in a window as easily as you send email. You will also be able to share data from your workstation with others - for instance, engineering drawings or presentations and spreadsheets. A variation of videoconferencing is broadcast video. One person gives a presentation and broadcasts it to many people, while the audience can interactively ask questions through video conferencing capabilities. Software-only Video Playback Video software playback displays stored video without any additional hardware. Generally, the video is compressed to ease the storage requirements. This type of application is very useful for training and presentations or whenever someone only needs to play back video, rather than capture, edit, or store it. Video Editing Video editing enables you to capture video clips, then manipulate and store them. Different aspects include dropping and duplicating frames, creating special effects, synchronizing audio with the video, splicing clips together, and so on. This capability is very important for high-quality video production, but also for creating presentations, demos, training applications, and so on. Education and Training Full-motion digital video can transform computer-based training from a slide presentation into a live presentation. Opportunities abound for sales training, just-in-time technical training, occupational training, on-line documentation, and computer-based education courses. There are two categories of customers for these applications, each with different requirements. o Users of video authoring software, such as developers of training materials. need the software plus the video capture and compression capability. o Users of training materials may only need the developed materials, with video decompression and display capability. Interactive Presentations and Information Access Multimedia presentations are very similar to the applications described under education and training. Specific opportunities include interactive kiosks in public locations (such as instructions in a train station showing how to purchase and use tickets) and interactive commercial presentations (such as video presentations of a cruise ship in a travel agency where the customer can pick an activity or port-of-call and see a video of the selection). Once again there will be users requiring authoring capability (including video capture) and others requiring only display capability. Professional Video Productions Video productions, for broadcast video (such as television commercials and flying logos) or for distribution on CD-ROM (video games and sales material), can be planned, created, and edited using workstation video capability. Corporate Custom Applications As full-motion video on the workstation becomes more accessible, its use in corporate applications will become more commonplace. An initial application includes remote medical imaging for diagnosis and surgical planning. Key Video Concepts Full-motion digital video is actually a combination of several, related, hardware and software technologies for video capture, video compression and decompression, video transmission over a network, video display in a workstation window, and video archiving on disk or other storage media. Video Capture (input) The video we are all used to seeing on our televisions and VCRs is an analog signal. To capture the video signal, the video data must be digitized and stored in memory or in the frame buffer. The digitization requires special purpose (but commonly available) hardware and produces a digital image similar to a Sun raster file. For the image to be saved it must be transmitted across the available buses to memory. Capturing and storing or transmitting a continuous video sequence at 640 x 480 resolution requires from 9 to 27 Mbytes/second of bandwidth for 8-bit or 24-bit images. This stretches or exceeds many system buses such as SBus, LANs (Ethernet), or WANs (ISDN). Therefore, real-time video capture will generally also include real-time video compression to reduce the bandwidth required. (This is discussed further below.) Compression is also required to save video data. Without compression, one minute of video data requires almost a gigabyte of storage. Video capture is needed for many, but not all, full-motion video applications. It is obviously necessary for every workstation used for video-conferencing. It is also required for many video authoring situations (though the video capture capability can often be a shared resource). Full Motion Digital Video Display Display of full-motion digital video generally means starting with video that has already been digitized and compressed and is received from some network connection (Ethernet or ISDN), from a live video capture device (camera or VCR), or from some storage media (disk or CD-ROM). To display the video must be decompressed (preferably in real-time, e.g. 30 frames per second) and sent to the frame buffer for display in a window. Full Motion Digital Video Compression/Decompression Video compression and decompression is one of the areas of technology currently receiving the greatest amount of attention. As discussed earlier, video compression is a requirement for reducing network and bus bandwidth needs and for reducing space for video archiving. There are many ways to compress and decompress video, with different costs and benefits, both monetary and performance. The many techniques available or under development differ in a variety of characteristics. Characteristics of Compression/Decompression Techniques Some of the characteristics of compressing and decompressing full-motion video include lossless vs. lossy compression, compression ratio, intraframe vs. interframe compression, computation cost, and symmetric vs. non-symmetric compression. o Lossless vs. Lossy Compression Lossless compression means there is no information lost when an image is compressed and then decompressed; that is, the decompressed image is identical to the original image. Lossless decompression is often used for saving space on disk storage text and binary data. Lossless algorithms tend to provide only a small amount of compression - perhaps a 2:1 uncompressed-to-compressed ratio. Certain applications, such as medical imaging or satellite data interpretation, require lossless compression. The video compression algorithms used for full-motion digital video are generally lossy algorithms, that is, not identical to the original image. The amount of information loss, and thus the final image quality, varies considerably with the different techniques and within a single technique according to the parameters chosen. As a general rule, the greater the compression ratio, the greater the information loss. o Compression Ratio Compression ratio describes the change in size, or amount of storage space required, one achieves in compressing the image or video. o Intraframe vs. Interframe Compression Intraframe compression compresses a single image at a time, without regard to the previous or succeeding images. Other algorithms do intraframe compression and then do additional interframe compression. This technique is much more costly to encode but, for a given compression ratio, provides a higher quality sequence of images. This provides the very high compression needed for video conferencing over LANs and WANs. Techniques that are intraframe-only are more appropriate for still images. o Computation Cost Different compression techniques vary considerably in the amount of computation required to compress and decompress images. Some decompression techniques are relatively low cost (measured in time and money) and can be computed in software on standard workstations at reasonable speeds (for example 10-30 fps). Other techniques currently require special purpose hardware to perform compression or decompression at rates close to full-motion video. o Symmetric vs. Non-symmetric Compression A symmetric compression is one in which the computation cost for compression is roughly the same as the computation cost for decompression. A non-symmetric technique is one in which compression typically is significantly more expensive than decompression. Symmetric techniques have the advantage that specific hardware can be developed to provide both the compression and the decompression. Asymmetric techniques have the advantage of providing inexpensive playback without additional hardware. Compression Techniques As mentioned previously, there are a great many compression techniques in existence or currently under development. Some of the more common ones are described in the following paragraphs. o JPEG Joint Photographic Experts Group (JPEG) is close to being endorsed as an industry standard for still picture compression. It is an intraframe compression standard that achieves a ratio of about 20:1 r o MPEG Moving Pictures Experts Group (MPEG) is a video compression standard for full-motion video. It is an interframe method that can compress to a ratio of about 100:1. o Px64 Px64 is also known as H.261. This technique is a standard proposed specifically for video transmission over ISDN lines: that is, for video conferencing and videophone. o DVI Digital Video Interactive (DVI) is a proprietary video software architecture developed by Intel to run on their hardware. o RPZ - RPZ RPZ - RPZ is the Apple" proprietary compression/decompression technique and is part of their QuickTime` software for multimedia applications. Other Techniques There are also several lossless compression algorithms, including Run-Length Encoding and Huffman encoding. These tend to provide much less image compression. They are also often used in conjunction with the above techniques to provide some additional compression. Challenges Full-motion digital video on the workstation is currently possible and no longer a research question, but it is far from commonplace. The greatest challenge is to make video on the workstation inexpensive enough to have on every workstation, and easy enough to use so that it is no more complicated than email. The challenge of low cost is the easier one to meet. As CPUs become more powerful and as workstations are becoming multiprocessors, more video functions can be computed on a standard workstation. Furthermore, special- purpose chips to aid in video compression are becoming available and will advance along the price curve until they are on every system. Additional hardware, including cameras and higher speed networks, are also becoming more accessible. The challenge of ease-of-use is not so predictable. Widespread use is not likely to occur until multimedia presentations are as easy to produce as creating slides or displaying analog video on a VCR. Video conferencing will not be widely used until one can point and click and bring up a video conference window on the workstation. Furthermore, full-motion video must integrate seamlessly with the other aspects of multimedia - documents, fax, and audio.
---------------------------------------------------------------------------- The Florida SunFlash Multimedia: ISDN (6 of 6) SunFLASH Vol 40 #30 April 1992 ---------------------------------------------------------------------------- 6 ISDN Integrated Services Digital Network (ISDN) is a new service offered by many telephone companies that provides fast, high-capacity digital transmission of voice, data, still images and full-motion video over the worldwide telephone network. ISDN will soon be to wide area networking what Ethernet is to local area networking today. It will enable multimedia communication - voice, video, images and data combined - over the existing telephone network. ISDN will help workstation users integrate their telephone with workstation applications in a seamless way, increasing their productivity. In addition, ISDN will provide an alternate channel enabling customers to transmit information from one point to another in real-time at a reasonable cost. ISDN offers many times the speed of current analog modems, and twice the bandwidth of the leased lines commonly used today to carry video conferencing. ISDN Applications ISDN applications fall into two categories: o Basic applications in which ISDN replaces or enhances existing applications o New types of applications that integrate voice, images, video and data in ways that don't exist today Basic Applications of ISDN The basic application of ISDN is for wide area networking. When workstations come with an ISDN interface built in, just as they have an Ethernet interface today, your reach will not be limited just to the local network but will extend to the whole world. Some of the applications this basic capability enables are described in the following paragraphs. Replacement or Backup for Private, Leased, or Public Packet Switched Lines For most customers, the cost of an ISDN line is much less than that of a private line or leased line. For customers that can afford private lines, ISDN will provide a cost-effective alternative as a backup line. Most leased lines are 56 kilobits per second (Kbps), compared to ISDN speeds of up to 128 Kbps (aggregated) for basic rate ISDN. For customers that cannot afford the substantial fixed charges for leased lines, ISDN for the first time offers them equivalent bandwidth at a cost they can afford. The cost of ISDN will also be much less than public switched network access (X.25), especially in Japan and Europe. Telecommuting Working from home on a networked workstation will become a reality when ISDN becomes available at home. ISDN provides data transmission speeds that enable true client-server computing over a wide area network, making access from home practical. Workstations will require an ISDN terminal adapter (or an SBus card for SPARCstations) and software that allows TCP/IP (communication protocols used in the UNIX environment) over ISDN. Replacement of Data and Fax Modems Currently, 9600-baud modems are becoming a standard. However, the price range for such modems is $500-$1000. The price for ISDN adapters is currently in the $1000-$1500 range but they offer speeds that are about seven times greater than 9600-baud modems. New Applications of ISDN New applications made possible by ISDN technology can be discussed in three categories. These categories are not all-inclusive. Customers will find many more applications of the technology as it becomes widely available. Some of these applications are described in the following paragraphs. Telephone-Workstation Integration Telephones used in proprietary PBX systems currently provide functionality such as caller identification with a liquid crystal display (LCD). A workstation with a graphical user interface could provide a much more flexible and powerful display. This type of integration enables the following applications: o An automatic phone dialer linked with an address file or calendar application o A customizable answering machine application that can take messages or forward calls based on the identity of the caller o The integration of voice messaging (voicemail) with electronic mail Multimedia Communication/Collaboration A conference call between people at different locations that includes sharing each others' screens in a collaborative work environment will require point-to- point connections with real-time response. ISDN can enable this type of connection. Some of the applications in this category are: o Collaborative work environments. This could involve real-time screen-sharing between two or more people working on the same project. o Concurrent engineering. This would enable everyone involved in a project (including suppliers) access to shared work even if they are not connected to the same local area network. o Video conferencing. With proper compression/decompression, a reasonable quality video conference can be carried over the ISDN lines. For example, some of the video conferencing systems available today use two 56 Kbps switched lines, for 112 Kbps total. Vertical Applications There are certain market segments such as customer service, where computer users spend a lot of time on the phone. Any degree of automation that can integrate the phone and the computer will help improve service and increase efficiency. Some of the examples in this category are: o Customer service applications. ISDN's caller ID feature enables immediate access to the customer's records when a customer's call is received. o Technical support. A support person could easily look at a workstation screen and provide support remotely. o Voice response applications. o Intelligent operator terminals in telephone companies. Benefits of ISDN ISDN will benefit workstation users, system administrators, companies of all sizes, and the telephone company as well. o Workstation users will get better access speeds and higher transmission quality of voice and data. ISDN will make wide area networking and communications as easy as plugging a phone into the wall jack. It will also allow a viable telecommuting environment. Wide area networking will provide users with the functionality of today's local area network, but with the added benefit of access to people on other networks as well. o Telecommunication system administration can more easily accommodate changes when office moves occur. It will also reduce the network wiring requirements and maintenance costs. ISDN will make troubleshooting from remote locations easier. o Company benefits include reduced transmission costs resulting in enhanced employee productivity. There will be faster dial-up transmission at lower cost and higher profits in the long run. o For the telephone company, ISDN will reduce maintenance and upgrade costs and provide an increase in the data communication business for the telephone companies. These benefits will ultimately result in higher profitability. Key ISDN Concepts The following paragraphs describe some of the technical aspects of ISDN. Current Telephone Network In order to understand ISDN technology, you should first understand the current telephone network. Voice Call Routing Voice is analog in nature and so are most telephones today. When you make a call, your analog signal goes through the telephone company's central office (CO) switch which converts it to a digital signal. If it is a long-distance call, the switch routes the digital signal to an inter-exchange carrier (IEC) such as AT&T, US Sprint or MCI. The IEC then routes the call to the appropriate local central office which converts the digital signal back to an analog signal so that it can be used by the telephone on the receiving end. Data Call Routing Computers generate digital signals instead of analog signals, so two additional steps are required. A modem must convert the computer's digital signal into analog form before sending it to the telephone company's CO switch, and another modem must convert the analog signal back to digital so the receiving computer can understand it. In this process the data is converted between analog and digital forms at least four times in one transmission, thereby under-utilizing the network capacity. When voice is converted into digital form, a bit rate of 56 Kbps (kilobits per second) is often used to maintain the sound quality. Most modems today transmit data at 1200 or 2400 bps (with 9600 bps modems becoming more common). At 1200 bps, less than 2% of the 56 Kbps network capacity is used. ISDN Telephone Network Computer equipment is currently at a disadvantage because the telephone network was designed for voice. ISDN will remove this limitation, enabling companies and individuals to access a variety of multimedia services (voice, textual data, images, video) over a single international phone system serving as a global network. Integrated Services Digital Network (ISDN) is a worldwide public telecommunications network that will deliver a wide variety of data and voice transmission services. The first set of standards for ISDN were issued by the International Telecommunications Standards Organization (CCITT) in 1984. As ISDN becomes established globally, a variety of multimedia services (voice, textual data, images, video) can be supported over a single, homogeneous infrastructure. Digital communication will eventually prevail, resulting in enhanced quality and reduced costs of telecommunication. In addition, ISDN promises to make wide area networking as economical and accessible as local area networking is today. There are various types of ISDN that cater to different requirements. Unlike the current telephone network's in-band signalling, all ISDN services offer out-of- band signalling (signalling information and data are carried on different channels). This provides more flexibility in network operations and control. D Channels and B Channels There are two types of ISDN channels, D channels and B channels. o D Channel A D (or Delta) channel is a control channel. o B Channels B (or Bearer) channels are 64 Kbps clear channels for carrying data. Depending on the service offerings of the telephone companies, a number of B channels can be concatenated to provide higher bandwidths. BRI, PRI, and BISDN There are three types of ISDN, Basic Rate Interface (BRI), Primary Rate Interface (PRI), and Broadband ISDN (BISDN). o Basic Rate Interface (BRI) BRI is the interface that will eventually replace the current single-line telephones in residences and many businesses. BRI will be the standard interface to connect desktop devices such as telephones, fax machines and computers to the ISDN network. It normally provides two B channels and one D channel and is commonly referred to as a 2B+D interface. o Primary Rate Interface (PRI) PRI will become the standard interface between a PBX and a central office switch, or between two PBX switches. In the US and Japan, this service provides 23 B channels and one D channel (23B+D) with an aggregate rate of 1.544 Mbps. In Europe, the primary rate interface is 30B+D with an aggregate rate of 2.048 Mbps. These rates are different due to the requirement of maintaining compatibility with the existing digital systems in each country. Most phone companies in the US have applied to their regulatory agencies for rate approval for both BRI and PRI services. This means that ISDN will soon be available in most metropolitan areas in the US. o Broadband ISDN (BISDN) Broadband ISDN is the telephone companies' solution to the bandwidth limitations associated with BRI and PRI. As video and high-quality images become commonplace on desktops, their bandwidth requirements will exceed the capabilities of BRI and PRI. BISDN will offer a rates as high as 150 Mbps. However, BISDN is at least 2-3 years away from a trial stage in the USA. Signalling System #7 (SS7) For ISDN services to be useful, a user must be able to communicate to the rest of the world. SS7 is an international standard for common channel signalling that enables internetworking between the various ISDN exchanges. It is called "common channel signalling". The signalling information is sent on a separate, shared signalling channel. AT&T has been using a proprietary common channel signalling scheme, but is migrating its switches to SS7 to permit easy internetworking. Challenges ISDN's promise for integrating voice and data over a wide area network opens up possibilities for a universal network with a cost structure in line with current telephone service. ISDN does not require any change in our current wirings except for some minor additional investments in equipment. The US has been slow to implement ISDN so far, but the new aggressive plans published by telephone companies call for ISDN availability in all metropolitan areas by 1994. In contrast, ISDN is already available today in most of the European countries and in Japan. In fact, most of the developing countries are also migrating to ISDN. Japan, Australia, France, Germany, and Great Britain have ISDN available today for all businesses and many residential customers. Providing ISDN support as a standard feature will be a requirement for computer companies doing business in Europe and Japan. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ For information send mail to info-sunflash@sunvice.East.Sun.COM. Subscription requests should be sent to sunflash-request@sunvice.East.Sun.COM. Archives are on solar.nova.edu, paris.cs.miami.edu, uunet.uu.net, src.doc.ic.ac.uk and ftp.adelaide.edu.au All prices, availability, and other statements relating to Sun or third party products are valid in the U.S. only. Please contact your local Sales Representative for details of pricing and product availability in your region. Descriptions of, or references to products or publications within SunFlash does not imply an endorsement of that product or publication by Sun Microsystems. John McLaughlin, SunFlash editor, flash@sunvice.East.Sun.COM. (305) 776-7770.