Everything you wanted to know about MPEG-4 / DivX, but were hesitant to ask Part 4
DivX: 3.22
In January 2000, the following version of DivX was created: 3.22 or 3.11 VKI (Variable Keyframe Interval). It has improved decoding algorithms and reliability. In May, DivX Networks was born, founded by Gej with former MP3.COM director Jordan Greenhall and Joe Bezdek. In July, DivX Networks launched the Majo project, which launched OpenDivX in January 2001. OpenDivX is incompatible with 3.11 and has nothing to do with it except name. In August 2001, DivX Networks released their own DivX 4.0 and they froze open source. Before version 4.12 of the codec, all previous versions were worse than DivX ;-).
In March 2002, the first commercial version of DivX 5.0x appeared. The free base option creates a video stream that conforms to the ISO certified version of the MPEG-4 format. While the commercial Pro version fully supports global motion compensation, B-Frames (encoded frames with two-frame support, B = bidirectional) and QPel (motion recovery method designation, Q = 1/4).
In the summer of 2003, DivX Networks announced the release of the 5.1 codec which, thanks to the technology implemented to evaluate visual frames, allows you to obtain better results with lower bit rates than with previous versions. This codec will improve the quality of movie playback on “weak” computers and consumer devices.
In 2004, the release of the DivX Q version is expected, which, according to the developers, should be twice as efficient as the current 5.1x.
In addition, DivX Networks plans to create a solution from a single source. It is planned to use our own development as a container for video and audio tracks (main reasons for incompatibility). According to DivX Networks, the AVI format provides the best storage option, but requires minor modifications. Licenses and audio format are being negotiated.
In parallel, an independent team based on OpenDivX created the less popular XviD format.
Audio formats in MPEG-4
The audio track in MPEG-4 can be mono, stereo, and even multi-channel AC3, which is used similarly on DVD. Supported sound formats: MP3, Ogg Vorbis, WMA, ACC, VGF, AC3 and others.
The most popular is MP3 (Very Evil Editor comment: it would be more correct to say MPEG-1 Layer3, but we must admit that the established name is still MP3). Currently, the pure MP3 is compatible with acoustic systems and all modern DVD players, the production of portable devices and car radio recorders that play MP3 has been launched. Thus, MP3 became the first massively recognized audio storage format after Audio-CD. Despite the fact that MP3 appeared a long time ago, the newer formats that claim their place have not yet been able to reach the same level of popularity. This also applies to the development of Microsoft’s WMA (Windows Media Audio) and VGF, a joint creation of Japanese firms NNT and Yamaha, and MPEG-2 AAC (Advanced Audio Coding – Advanced Audio Coding), one of the attempts to improve MP3.
