Several developments over the last few years have increased interest in streaming media technologies. Among them are the following:
Broadband networking technologies such as ADSL and Cable modems became available in many metropoli- tan areas. End-users for the first time had reasonably priced access to approximately 256 to 768 kbps, or sometimes up to 1.5 Mbps, downstream bandwidth. Advances in compression technologies have emerged that allow compressing full-screen NTSC video into a stream requiring less than 1 Mbps of bandwidth. The MPEG-4 standard [1] was one of the widely discussed and publicized techniques.

One of the first implementations of an MPEG-4 style codec was available from Microsoft. The implementation did not fully comply with the MPEG-4 standard, however it demonstrated the very high compression ratio achievable (more than 300:1). Therefore, it became feasible, for exam- ple, to store the contents of a DVD (4.7 GB capacity and compressed with the older, less efective MPEG-2 standard) on a CD-ROM (650 MB capacity). Originally Microsoft\'s software only allowed decoding of media. However, after it had been slightly altered, both encoding and decoding were possible. This altered version became widely known as \"DivX;-)\" [2]. The early versions of the DivX codec were not fully MPEG-4 ISO standard compliant. For example, originally it did not use the MPEG-4 ISO standard le for- mat. More recently, that fle format has become an option, but is not yet very popular. Instead the media data is com- monly stored in the Microsoft AVI (Audio Video Interleave) fle format [3], which is a special case of the Resource Inter- change File Format (RIFF). Furthermore, most of the DivX fles available on the Internet use MPEG-1 layer 3 audio encoding (popularly known as MP3) and not the MPEG-4 audio codec.