Streaming video is a sequence of “moving images” that are sent in compressed form over the Internet and displayed to the viewer as they arrive. Streaming media is streaming video with sound. With streaming video or streaming media, a Web user doesn’t have to wait to download a large file before seeing video or hearing sound. Instead, the media is sent in a continuous stream and plays as it happens. The user needs a player, which is a special program that decompresses and sends video data to the screen and audio data to the speakers. A player can be an integral part of a browser or downloaded from the software manufacturer’s website.

Major streaming media and video streaming technologies include RealNetwork’s RealSystem G2, Microsoft Windows Media Technologies (including its NetShow and Theater Server services), and VDO. Microsoft’s approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. (The program that does the compression and decompression is sometimes called a codec.) Microsoft technology offers audio streaming at up to 96 Kbps and video streaming at up to 8 Mbps (for NetShow Theater Server). However, for most Web users, streaming video will be limited by the data speeds of the connection (for example, up to 128 Kbps with an ISDN connection). Microsoft streaming media files are in Advanced Streaming Format (ASF).

Video streaming is usually sent from pre-recorded video files, but can be distributed as part of a live stream. In a live broadcast, the video signal is converted to a compressed digital signal and transmitted from a special web server that can multicast, sending the same file to multiple users at the same time.

Streaming media is audio and video that is transmitted on the Internet continuously or continuously, using packet data. The most efficient reception of broadcast media requires some form of broadband technology, such as a cable or DSL modem. A packet is the unit of data that is routed between a source and a destination on the Internet or any other packet-switched network. When any file (email message, HTML file, Graphics Interchange Format file, URL – Uniform Resource Locator request, etc.) is sent from one place to another on the Internet, the Transmission Control Protocol (TCP) layer of TCP/IP divides the file into “chunks” of an efficient size for routing. Each of these packets is numbered separately and includes the Internet address of the destination. Individual packets of a given file can travel different routes through the Internet. When they have all arrived, they are reassembled into the original file (by the TCP layer at the receiving end).

A packet switching scheme is an efficient way to handle transmissions on a connectionless network like the Internet. An alternative scheme, circuit switched, is used for networks allocated for voice connections. In circuit switching, the network lines are shared among many users as in packet switching, but each connection requires the dedication of a particular path for the duration of the connection. “Packet” and “datagram” have a similar meaning. A protocol similar to TCP, the User Datagram Protocol (UDP) uses the term datagram.

MPEG, the Moving Picture Experts Group, develops standards for digital video and digital audio compression. It operates under the auspices of the International Organization for Standardization (ISO). The MPEG standards are an evolving series, each designed for a different purpose. To use MPEG video files, you need a personal computer with sufficient processor speed, internal memory, and hard drive space to handle and play the typically large MPEG file (which has a filename suffix of .mpg). You also need an MPEG viewer or client software that plays MPEG files. (Note that .mp3 file suffixes indicate MP3 (MPEG-1 audio layer-3) files, not standard MPEG-3 files.) You can download commercial MPEG players or shareware from various sites on the Web.

The term codec is an acronym meaning “compression/decompression.” A codec is an algorithm, or specialized computer program, that reduces the number of bytes consumed by large files and programs. To minimize the amount of storage space required for a complicated file, such as a video, compression is used. Compression works by removing redundancies in the data. Compression can be done for any type of file, including text, programs, images, audio, video, and virtual reality (VR). Compression can reduce the size of a file by a factor of 100 or more in some cases. For example, a 15 megabyte video could be reduced to 150 kilobytes. The uncompressed file would be too large to download from the Web in a reasonable amount of time, but the compressed file could typically be downloaded in a few seconds. For visualization, a decompression algorithm would have to be used to “undo” the compression.

There are numerous standard codec schemes. Some are used primarily to minimize file transfer time and are used on the Internet. Others are intended to maximize the data that can be stored in a given amount of disk space or on a CD-ROM. Codecs are used in many popular Internet products, including QuickTime, Netmeeting, Cu-Seeme, and VDOphone.

Flash is popular authoring software developed by Macromedia and is used to create vector graphics-based animation programs with full-screen navigation interfaces, graphic illustrations, and simple interactivity in a smoothed, resizable file format that is small enough to be transmitted over a normal modem connection. The software is ubiquitous on the Web, both for its speed (vector-based animations, which can adapt to different screen sizes and resolutions, play while downloading) and for the fluid way it renders graphics. Flash files, unlike animated but raster GIFs and JPEGs, are compact, efficient, and designed for optimized delivery.
Known as a do-it-yourself animation package, Flash 4 gives web designers the ability to import artwork using any bitmap or illustration tool they prefer, and create animations and special effects, as well as add sound and interactivity. The content is then saved as a file with a .SWF file name extension.

Internet users with Intel Pentium or Power Macintosh processors can download Flash Player to view Flash content, which works across multiple browsers and platforms. Flash is praised for being one of the most accessible plugins on the Web. According to an independent study cited by Macromedia, more than 90 percent of Internet users already have Flash Player installed. Adobe recently acquired Macromedia in a $3.4 billion deal.