Everything you wanted to know about MPEG-4 / DivX, but were hesitant to ask Part 3
Mpeg-4
Truly revolutionary is MPEG-4, which was officially completed in 1998. But since MPEG-4 is, in fact, a set of tools, they extend and complement each other. The last such additions to the standard were made in May of this year. It has become an extension of MPEG-1 and MPEG-2 and offers many innovative solutions, not all of which have found application in multimedia content and devices.
MPEG-4
The MPEG-4 standard was conceived as a way of transmitting transmission media, mainly video, over low-bandwidth channels. Unexpectedly, it gained popularity among users, thanks to the fact that it allowed to place feature films of one and a half hours to two in good quality on a single CD and to exchange video files on the Internet.
The MPEG-4 standard defines the principles for working with the digital representation of multimedia data in three areas: interactive multimedia itself (including products distributed on optical discs and on the Web), graphic applications (synthetic content) and digital television – DTV. . In fact, the format sets the rules for organizing the environment and the environment is object-oriented. It not only deals with streams and media matrices, but also with media objects.
With the same bit rate and certain encoding conditions, the image quality of a movie in MPEG-4 can be comparable or even better than when using MPEG-1 or MPEG-2. The video compression algorithm in MPEG-4 works in the same way as in previous formats. When encoding a source image, the codec saves keyframes and, instead of storing intermediate ones, predicts and stores only information about changes in the current frame relative to the previous one. The information obtained in this way is saved in a file. Sound compression is most often done in MP3, Ogg Vorbis, WMA formats. However, it is possible to use any codec, up to the six-channel AC-3 used on DVD.
The story behind DivX
The original DivX codec 😉 3.11 Alpha is a cracked version of MPEG-4 Version 3 (MP43c32.dll). The authors of the patch, known by the nicknames MaxMorice and Gej, published it in September 1999 on their website. It is no coincidence that the emoticon appeared in the title. At that time, the American company Circuit City was trying to commercialize the Digital Video Express (DIVX) Pay-per-View (Pay-per-View) video system. The business idea was to sell movies on CD, which would have been cheap but paid to see it again. Back then, hacking into the Digital Video Express security system was the target of many American hackers. Before this could be done, DivX disappeared from the market for financial reasons, and French programmers MaxMorice and Jerome “Gej” Rota immortalized it in the name of the new format.
