Video (movie) files are a popular digital media content type on the Web. They are used for almost every purpose that analog video is used. On the web, you can find everything from videos about Comet Shoemaker-Levy to trailers for the latest television shows and movies. Naturally, there is quite a bit of home video of babies, pets, and vacations.
The four de facto video file formats used for publishing video on the Web in decreasing order of popularity are:
QuickTime is the most popular movie file format on the Web for video files with audio tracks. In particular, the Cinepak (Compact Video) compression scheme for QuickTime is popular because it produces files which are small (although not as small as MPEG-1 system files) and playable on almost every modern PC, Macintosh, or workstation.
The MIME typing mechanisms used by your web server expect QuickTime movie files to have one of the following filename extensions: .qt or .mov. Use of any other extension will result in incorrect typing of the file.
MPEG-1 movie (video) files are a popular file format for movies on the Web which don't require audio tracks. This is because MPEG-1 provides the best highest compression of movies of any of the popular formats.
MPEG-1 system files which contain both video and audio streams have not yet gained popularity because there are few players that can adequately play back synchronized audio and video streams. However, as hardware and software implementations improve and faster microprocessors become available, MPEG-1 will grow in popularity as a file format for movies with audio.
The MIME typing mechanisms used by your web server expect MPEG-1 movie files to have one of the following filename extensions: .mpeg,.mpg, or .mpv. MPEG-1 system files must have one of the following extensions: .mps or .sys. Use of any other extension will result in incorrect typing of the file.
A. Of course you have to have some kind of video card installed in your computer. You will also need to have certain extensions installed and an application to play the videos. Most Windows based PCs and Macintosh computers already have the necessary software installed.
A. That depends on the file size, frame rate and data limit (see questions below). For a one-minute clip, a 160 movie takes about 5.5 megs., a 240 movie about 9 megs. and a 320 movie about 16.2 megs.
A. There are three primary frame sizes for QuickTime movies: 160x120, 240x180 and 320x240. You might think bigger is better, but that is not necessarily so -- remember your audience and the limitations of the network. The size of the frame affects the frame rate. Reducing the frame size increases the frame rate of the movie.
A. A very acceptable frame rate for QuickTime movies is15 frames per second. This is half as many frames per second as television which plays at 30 frames per second. At 15 fps motion still appears fluid even when someone is talking.
A. The data limit is increased in proportion to the frame size. Larger frame sizes (more picture to view) require a higher data limit to keep the picture looking good.