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25.3. Video File Formats

As with audio, in the early days of the Web, adding video to a web page meant using one of the currently available video formats (such as QuickTime or AVI) and linking it to a page for download. The evolution of streaming media has changed that, and now adding video content like movie trailers, news broadcasts, even live programming to a web site is much more practical and widespread.

This section looks at the video formats that are most common for web delivery.

25.3.1. QuickTime Movie (.mov)

QuickTime is a highly versatile and well-supported media format. While originally developed as a video format, it has evolved into a container format capable of storing all sorts of media (still images, audio, video, Flash, and SMIL presentations). For the complete list of file formats supported by QuickTime, see http://www.apple.com/quicktime/specifications.html.

QuickTime, a system extension that makes it possible to view audio/video information on a computer, was introduced by Apple Computer in 1991. Although developed for the Macintosh, it is also supported on PCs via QuickTime for Windows. QuickTime has grown to be the industry standard for multimedia development, and most hardware and software offer QuickTime support. Both Netscape Navigator 3.0+ and Internet Explorer 3.0+ come with QuickTime plug-in players, so the majority of web readers are able to view QuickTime movies right in the browser.

25.3.1.1. Streaming

QuickTime movies can be streamed using a number of streaming server packages, including Apple's QuickTime Server for Mac OS X or its open source Darwin Streaming Server for Unix. To give the illusion of streaming from an HTTP server (pseudo-streaming), create FastStart Quicktime movies, which begin playing right away and continue playing as the file downloads.

25.3.1.2. Creating QuickTime movies

You can take care of rudimentary video editing, such as deleting and rearranging, right in Apple's free QuickTime Player. The QuickTime Pro version ($29.95) offers more features and is sufficient for most basic tasks. For advanced video editing, use a professional video editing tool such as Adobe Premier or AfterEffects (most video editors support QuickTime). You may also use a file converter, such as Cleaner from Terran Interactive (http://www.terran.com) to convert existing files to QuickTime format.

Other video editing applications for the Mac include iMovie (which ships free on newer Macintoshes) and Final Cut Pro, a more professional video editing program.

An important step to remember when saving a movie is to make it self-contained. This process resolves all data references and prepares the file to go out on the Internet on its own. You will also be asked to pick a codec (QuickTime supports several). Cinepak is a good general purpose codec; Sorenson is more efficient but not as well supported.

25.3.2. RealMedia (.rm)

RealMedia is the industry standard streaming media format. RealNetworks (which used to be Progressive Networks) first launched its streaming video capabilities in Version 3.0 of its RealMedia line of products (of which RealAudio is the star component). RealMedia files (.rm) are viewed using RealPlayer 3 and higher. The wide distribution of RealPlayer and a proven track record of effective playback have made RealNetworks' products the de facto standard for adding streaming media to a web site.

The components of the RealMedia system (RealPlayer for playback, RealServer for serving simultaneous streams, and RealProducer for creating .rm files) are the same as for RealAudio. The descriptions of each component as discussed in Chapter 24, "Audio on the Web" apply to video as well. RealMedia movies are encoded using a proprietary codec built into RealProducer and RealPlayer.

For more information, visit the RealNetworks site at http://www.realnetworks.com. For consumer-oriented information and downloads, see http://www.real.com.

The following summarizes the RealAudio format:

Good for

Long-playing video clips and live broadcasts to large numbers of people.

Delivery

Streaming (via RTSP), pseudo-streaming (via HTTP).

Creation tools

One of the RealNetworks encoders (such as RealSystem Producer Plus) or a third-party tool such as Cleaner 5 from Terran Interactive.

Player

Freely available RealPlayer, Commercial RealPlayer Plus (with added features), RealPlayer plug-in in Netscape Navigator and Internet Explorer.

25.3.3. Windows Media (.wmv or .asf)

Windows Media is the new standard for audio and video, created by Microsoft and therefore very closely integrated with the Windows OS. The Windows Media Player is capable of playing Microsoft's proprietary Windows Media Video (.wmv) and Advanced Streaming Format (.asf ), as well as a number of other formats such as AVI, MPEG, MP3, and QuickTime.

The Windows Media system is also comprised of Windows Media Server (which runs only on Windows NT/2000) and tools for creating .wmv and .asf files (Windows Media Author and Windows Media Encoder, which are both Windows only). These components, as well as the methods for adding Windows Media to a web page, are discussed in Chapter 24, "Audio on the Web".

Windows Media movies are encoded using the proprietary Windows Media Video codec (currently in Version 8) designed especially for the Windows Media system. Users must have the Windows Media Player 8 in order to play movies encoded with the Version 8 codec. Use Version 7 if you don't want to force your users to upgrade (or if the processing power of your PC cannot handle the demands of the Version 8 encoder).

For more information about Window Media, visit Microsoft's site at http://www.microsoft.com/windows/windowsmedia/.

The following summarizes the Windows Media format:

Good for

Long-playing video and live broadcasts.

Delivery

Streaming, download.

Creation tools

Windows Media Encoder for converting to Windows Media format,Windows Media Author for creating synchronized multimedia presentations. See the Windows Media site for a complete list of creation tools at http://www.microsoft.com/Windows/windowsmedia/en/overview/components.asp.

Player

Media Player (shipped with Windows OS), available as download for the Mac as well as a variety of handheld devices that support Windows CE.

25.3.5. MPEG (.mpg or .mpeg)

MPEG is a set of multimedia standards created by the Moving Picture Experts Group. It supports three types of information: video, audio, and streaming (which, in the context of MPEG compression, is synchronized video and audio). MPEG was initially popular as a web format because it was the only format that could be produced on the Unix system.

MPEG files offer extremely high compression rates with little loss of quality. They accomplish this using a lossy compression technique that strips out data that is not discernible to the human ear or eye.

There are a number of MPEG standards: MPEG-1 was originally developed for video transfer at VHS quality; MPEG-2 is a higher-quality standard that was developed for television broadcast; other MPEG specs that address other needs (such as MPEG-4 and -7) are currently in development. MPEGs can be compressed using one of three schemes, Layer-I, -II, or -III. The complexity of the coding (and therefore the processor power needed to encode and decode) increases at each level. Due to this complexity, you need special encoding tools to produce MPEG videos.

MPEG-1 (which uses the .mpg or .mpeg suffix) is the most appropriate format for web purposes. MPEG-2 files are rare except in broadcast studios and on DVDs and are not well suited for web delivery.

To learn more about MPEG, visit the MPEG web site (http://www.mpeg.org).

The following summarizes the MPEG movie format:

Good for

High-quality video.

Delivery

Streaming, download.

Creation tools

Cleaner 5 by Terran Interactive (http://www.terran.com/cleaner/).

Player

Windows Media Player, QuickTime Player.



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