Multimedia Systems, Architectures and File Formats

ASF. Active Streaming FormatMicrosoft's ASF format for multimedia delivery.
Download the player
An excellent overview of Microsoft's AVI file format by John F. McGowan.
QuickTime by Apple is a very mature and rich system of software for capturing, viewing, manipulating and delivering multimedia. It consists of three layers:
  • File format layer, which defines a multimedia container.
  • Media abstraction layer, which removes platform dependence, and allows access to hardware acceleration.
  • Media services layer, which allows the modular addition of services such as video decompression.
    This architecture enables it to work on multiple platforms and has interoperability with other systems such as Microsoft's AVI and the emerging digital video camera standard DV built into it. It can handle video, audio and other data types such as time-code, text and 3D. It does not by itself define a compression standard, but has compression codecs that can be added to it as components, such as MPEG-1, JPEG, Cinepak etc. Originally Macintosh software, it can now be run on IBM compatibles and Silicon Graphics computers as well as Apple Macintoshes.
    QuickTime can also work with other multimedia file formats, which reduces the need for conversions from one format to another, and also reduces the concomitant generational quality loss that conversion often causes.
    A disadvantage of QuickTime for Internet viewing is that the entire file has to be downloaded before it can be viewed, resulting in a tedious wait. Third party software, called Moviescreamer, provided by Digigami aims to resolve this problem by preprocessing the QuickTime file, and allowing a part of it to be viewed even as the rest is still being downloaded. This is not a complete streaming video solution, but at least allows a preview. A demo is available here but you need a QuickTime player, which can be downloaded from one of the links below.
    QuickTime movie samples
    Technology brief
    Win 95 Quicktime player
    Macintosh Quicktime player
    DV
    AVI
    OpenDML