ActiveMovie Technology

ActiveMovie, a Microsoft API that was announced in March 1996, is receiving wide support in the computer industry as “the next generation of cross-platform digital video technology for the desktop and the Internet”, according to a Microsoft press release. It is being touted by industry observers as the cure for the deficiencies in Microsoft’s VfW and Apple’s QuickTime. ActiveMovie removes most of the limitations imposed by VfW, such as the small number of supported file formats, limited I/O throughput, inconsistent driver models, and the lack of driver compatibility between Windows 95 and Windows NT. ActiveMovie solves these problems primarily by using the Component Object Model (COM) as its foundation, the most widely recognised implementation of which is Object Linking and Embedding (OLE). Various objects in the model control such actions as decompressing data, adjusting volume levels, and so forth.

Building ActiveMovie on the COM architecture, Microsoft has provided application developers with a digital video API that has a number of benefits, such as independence from operating systems and programming languages, thus allowing the same or similar code to be used on multiple platforms. ActiveMovie also supports more popular formats – including MPEG audio, .WAV audio, MPEG video, and Apple QuickTime video – making it especially convenient for Internet and intranet application builders. Moreover, ActiveMovie is integrated with Microsoft’s DirectX technology. This allows it to automatically take advantage of accelerating video and audio hardware to allow each computer to perform according to its capabilities. For example, ActiveMovie improves the video playback quality of AVI and QuickTime movies by using DirectDraw, a DirectX component, along with features present on many standard graphics cards.

One of ActiveMovie’s most impressive features is the ability to decode MPEG video using either hardware or software, including MPEG-2. It can decode MPEG-1 entirely in software and provide high-quality playback on Pentium-based systems. Or, if the computer has hardware for decoding MPEG, ActiveMovie can use DirectMPEG, another component of DirectX, to access this hardware and play back the video seamlessly.

ActiveMovie has recently been enhanced and is now called DirectShow. The largest enhancement included in this change is that DirectShow supports DVD while ActiveMovie did not.