Previous Section | Next Section
Table of Contents

A wide range of codecs are available for delivering rich multimedia to the desktop, but not all possible codecs are listed in this section. Which codec to use depends on application requirements and bandwidth limitations. Storage requirements are also a consideration, because richer multimedia require higher bandwidths. High-quality video codecs such as Indeo Video 5.0 and MPEG1 deliver good-quality video at about 1.2 Mbps of bandwidth. Use of MPEG1 and Indeo Video 5.0 may be good for applications delivered on CD-ROM, but great-quality video can be obtained by using MPEG2 video. This compression algorithm provides broadcast-quality video at about 4 Mbps. Although it requires a large amount of storage, it is the codec of choice for DVD-ROM.

The type of compression used by the application will determine how many assets can be stored on the CD. Table B-2 lists some of the possible audio and video codecs and how many minutes of the assets could be stored on a CD- or DVD-ROM. The large storage capacity of CD- and DVD-ROM make them much better for delivering rich multimedia assets.

Indeo Video 5.0 compression and playback software allows for high-quality, scaleable video content to be viewed over the Internet or intranet quickly and easily. Its progressive download technology allows you to start seeing video as it downloads. Users have the option of continuing to view the video while determining whether to save it on a hard disk. Indeo Video 5.0 allows you to create high-quality video for Web pages and be assured that users can experience your video at the best level of quality that the connection speed will allow. Indeo Video provides the best compromise between good quality and scaleable bandwidth.

Indeo Video 5.0 is a good codec for delivering high-quality video on CD-ROM as well. The three sample channels were created using Indeo Video 5.0. The codec is ideal for channels requiring video on demand on the Internet as well as video stored on CD- or DVD-ROM.

Rich video should consist of a full-screen experience that is a minimum of 24 frames per second (FPS). For broadcast quality, MPEG2 is the primary choice. It provides good-quality video and is typically used in satellite broadcasting or for distribution on DVD-ROM. Software playback of 24-FPS MPEG2 requires a minimum of a 266-MHz Pentium^® II Processor based system with hardware motion compensation on the graphics card. This setup provides the best-quality video for the consumer. With a bandwidth ranging from 2–8 Mbps, pushing it across the Internet is not practical across 28.8-Kbps modems. For broadband, MPEG2 is a viable choice and could be delivered to the end user across satellite, cable and possibly ADSL modems.

MPEG1 is a viable alternative for delivering VHS quality video on CD-ROM. Requiring from 1–2 Mbps, the codec requires slightly less bandwidth than MPEG2. The quality of the video is not as good but can be used to provide video for distribution on CD-ROM. Microsoft’s Netshow* and Xing’s Streamworks* provide real-time video streaming servers for real-time broadcast across a network. The high-bandwidth requirement limits its use to private intranets, networks, or for possible use in broadband delivery.

For delivery across 28.8-Kbps modems, a variety of codecs can be streamed across the Internet. MPEG4 is designed to be delivered across 28.8-Kbps modems. The video quality is acceptable and provides a frame rate on the order of 4–8 FPS. MPEG4 is also scaleable up to 56 Kbps and is a relatively good solution for delivering low-end video.

H.261 is a good low-end codec that is scaleable across a variety of bandwidths. The algorithm is typically used for video conferencing and can provide a good solution for live video broadcasts across the Internet or private networks. It is highly scaleable, and for bandwidths from 64–400 Kbps, it provides reasonable video quality and frame rate.

Which codec you choose depends on the application, and whether the video is being delivered in real time. For channels, the best possible choice is MPEG2. Video can be distributed on CD- or DVD-ROM to provide the end user with the best-quality video. Preserving the broadcast quality of movies and music videos are important for the user’s experience.

A variety of streaming audio codecs provides audio across the Internet. These codecs can also be used to store the audio. Streaming audio can be used in channels to provide live concerts, interviews with artists, presentations and music clips. Creating a streaming audio codec requires an audio server and an audio source. Typically, an audio codec requires a Microsoft Windows NT* Server and a standard audio card to deliver streamed audio on the Internet. Most audio codecs require the client software to be loaded on the user’s machine.

Intel Indeo audio provides high-quality compressed audio for Internet, intranet, and multimedia applications. It can compress both music and voice audio as much as 8:1 with no appreciable loss in quality. Intel Indeo audio works in conjunction with Indeo Video 5.0's Progressive Download capability to allow richer, fuller, multimedia Web sites.

The Indeo audio codec comes included with the Indeo video 5.0 codec and progressive download filter. Movies containing compressed Indeo video 5.0 and Indeo audio streams are created using Intel's Indeo video 5.0 Progressive Download Publisher tool.

Real Audio* consists of a Real Audio player, Real Audio server and Real Audio encoder for delivering real-time audio across the Internet. The Real Audio* encoder feeds the server for delivery of the stream across the network. Real Audio uses HTTP streaming for delivery of audio across the Internet. Real Audio can be delivered live or stored in a file. You can download the player for free from the Real Audio site.

Real Audio* provides a scaleable audio solution that can deliver a variety of audio streams. Audio quality ranges from AM to close to CD-quality sound. At 28.8 Kbps of bandwidth, the audio is close to FM quality. The Real Audio server is capable of delivering either UDP or TCP packets to the user. UDP does not guarantee the delivery of packets across the network. UDP is often used in real-time streaming, since there is no need to retransmit when the content is in real time. The real-time audio server can be set up to deliver real-time streaming audio from 28.8-Kbps to ISDN rates, depending on application requirements.

Xing provides StreamWorks* products for delivery of MPEG1 and MPEG2 audio. The standard audio codecs provide scalability depending on the application. LBR can be scaled from 8–16 Kbps, MPEG2 can be scaled at 8–80 Kbps, and MPEG1 can be scaled from 32–192 Kbps. The ability to scale allows the audio to be compressed according to the fidelity requirements of the content. This maximizes the efficient use of bandwidth across the Internet.

The Xing StreamWorks* solution also includes a player, server and transmitter for delivering streaming audio or video. The Xing StreamWorks* server delivers live and stored audio over the Internet, and enables real-time transmission of MPEG audio and video using either multicast or unicast. This provides a scaleable solution for delivering low-bandwidth MPEG1 or MPEG2 audio and video up to high-quality MPEG 1 video. The standard implementation is one of the alternatives for delivering scaleable audio and video across the Internet.

Liquid Audio* provides a comprehensive solution for delivering online music to end users. It provides downloadable audio based on Dolby’s* digital compression technology. The solution includes a music server to store and stream real-time music to the end user, and the liquid music player can also download lyrics and artwork stored on the Web for use on a CD-album or in a piece of music. Electronic commerce is built so that music can be purchased online using credit cards. Liquid Audio provides a viable solution for electronic delivery of online music.

True Speech* is a relatively good-quality codec running at 8.5 Kbps. For voice applications, the True Speech* algorithm is useful for delivering low-bandwidth audio across the Internet in real time or as stored content. It could possibly be used in streaming audio applications that require voice only.

3D Realistic Sound Experience positions sounds in 3D space. Sounds can be created as if they are in front, behind, left or right in 3D space. Application sound can be even more realistic to the end user as he or she interacts with the channel. Sound effects such as reverberations and Doppler effects can give the sensation of cars approaching and then receding. This form of 3D audio animation gives the user the sensation of getting hit by sounds from various directions. 3D RSX can be incorporated into VRML 2.0 worlds or streamed across the Internet. By giving the user the best possible audio experience and a sense of direction when navigating 3D worlds, 3D RSX is a good alternative to 2D sound.

Most DVD movies digitized today use Dolby AC3* audio, which provides quality audio with a 12:1 compression ratio. Its high-quality compression makes it a viable codec for delivering a great audio experience with good compression. It is the standard choice for delivering video and audio on DVD-ROM.

The choice of audio codecs is dependent on the application. For live broadcast, a variety of solutions are available: Real Audio*, Xing StreamWorks*, and Liquid Audio* are just a few of the streaming solutions on the Internet. For audio storage, WAV and PCM audio are alternatives since they provide great quality. WAV audio was used in the music channel and could be delivered without compression across the net using push technology. It is also ideal for delivery on CD- and DVD-ROM. If a large number of music or audio samples are required, Real Audio*, MPEG1, MPEG2, MPEG3 and liquid audio* are alternatives.

Microsoft Netshow* provides a bandwidth scaleable solution for delivering streaming video, audio or data. It provides the ability to multicast or unicast streams on the Internet. The Netshow* 2.0 product line can synchronize the delivery of audio and graphics in the form of live presentations. Audio streams can be delivered in real time with synchronized Web surfing. Netshow allows the embedding of URL references in the stream, so Web pages can be pulled up while the audio is playing. For example, a live concert could be delivered while information about the band or advertising is pulled up at the same time through Web pages.

The Netshow *2.0 channel server consists of administrative tools for managing programs and channels. A single Netshow channel server can support multiple streams and deliver several streams of programming on the Internet. The Netshow server broadcasts events on the Internet using an ASX file. The simple file format specifies the program’s ASF file as well as the server that will deliver the programming. The Netshow administrative tools consist of a channel and program manager to manage and deliver live audio and video programming across the Internet.

The client software consists of a Netshow player, which is incorporated as an option in Internet Explorer 4.0. A Netshow file can be embedded in a Web page or can run as a stand alone application. Once the client is loaded on the user’s machine, he or she can view Netshow broadcasts.

The Netshow* server provides the capability of delivering audio, video and data programming on the Internet. Netshow 2.0 provides the administrative tools to define digital channels that can be scheduled for delivery using unicast or multicast. Acting much like a broadcast of TV channels, it allows for setting up channels that can deliver a variety of content scheduled at specific times.

Multiple channels can be delivered and broadcast 24 hours a day. The program manager defines the streams to be delivered, and the channel manager determines the how the stream is delivered on the Internet.

Announcements can be delivered to the end user describing a future programming broadcast that may match his or her programming interests. If the user is interested in the broadcast, he or she can select the program and watch it live. Broadcasts can also be stored in a file for delivery on demand.

The Netshow player is capable of running within a Web page or stand alone. In stand-alone mode, the user can watch a program of streamed audio, graphics or video. The user can watch the digital program without interaction, or interactive features can be included. The Netshow player is integrated with the latest version of Internet Explorer. Live events can be delivered to the user’s desktop as part of Internet Explorer’s active desktop.

The ASF format provides a method for synchronizing different data types and providing error correction for delivering audio and graphics across the Internet. Microsoft provides the Netshow* ASF editor, which allows for a multimedia show comprising the integration of video, audio and text. The ASF editor manages the bandwidth so that delivery of the different multimedia content fits within the expected bandwidth. The content is scaleable and can be set up to deliver content to modems, ISDN or intranet connections. With more bandwidth, better-quality video, audio and graphics can be delivered on a channel.

The Netshow* server can provide several ASFs created for different bandwidths. This gives the user a scaleable experience depending on network connection. Mixing video, audio and data provides a richer experience than any of them alone.

ASX files are generated to announce programs to clients. An ASX file is a basic file declaring the protocol being used, the name of the server and the ASF file being used. It redirects the user to the appropriate streaming servers, and can be included on any Web server and incorporated into any HTML reference.

The Netshow* 2.0 server is also capable of delivering files to the user. It can provide software updates to a large number of users with the same broadcast paradigm as delivering audio and video.

The Netshow* server allows for multiple channels to be set up and delivered. Multiple channels can be created to contain live broadcasts of video or audio. Stored content can also be delivered to the user and contain video, audio or data synchronized using ASF format. Much like TV broadcasting, Netshow channels deliver content at scheduled times.

Netshow’s* architecture provides for connecting several live servers to Netshow servers that deliver the streams to connected clients. The Netshow solution is highly scaleable and can deliver multiple digital broadcasts to a large number of users. According to Microsoft, a single Netshow server is capable of supporting up to 1,000 streams at 28.8 Kbps.

Microsoft Netshow* 2.0 supports a variety of audio and video codecs. Table A-5 lists some of the supported codecs. At 28.8 Kbps, reasonable-quality audio and video can be delivered to the user with MPEG4, Real Audio and H.263, but streaming audio provides a much better real-time experience.

*Other brands and names are the property of their respective owners.

© 1997 Intel Corporation. All rights reserved.

* Legal Information © 1998 Intel Corporation