MPEG-1 and 2 focussed mainly on compression of data, both audio and video. Even today, MPEG-2 keeps evolving and incorporating the new standards that are being laid out for higher compression retaining better quality. The goal of MPEG-2 is absolutely clear Coding of Moving Pictures and Associated Audio and it aims to do exactly that.
MPEG-4 on the other hand, is the start of a different way of looking at the coding of video. It is defined as the Coding of Audio-Visual Objects and all through the standard, objects are given a lot of importance. Transcoding, interoperability, error resilience, etc. are the other usual features. MPEG-4 now incorporates so many parts, that its too exhaustive to list here.
MPEG-4 became quite complex with all its syntax and header information. The organisation was so complicated that when H.264 came about, their official goal actually included “Simple Syntax specification” 😉 along with Highly improved coding efficiency. MPEG-4 however has now adopted the H.264 standard as part of their 14496-10 Advanced Video Coding section.
Coming to MPEG-7, this is formally named the Multimedia Content Description Interface and understanding, classifying, retrieving content is now the most important goal. High-level semantic information is the need of the hour and this standard provides several descriptors that could help to perform this analysis.
In the following months, I would like to try and review some of the descriptors (features) that are being used in the MPEG-7 standard. Ofcourse, the main intention is for me to learn them as usual 🙂
PS: There was no MPEG-3, 5, 6, 8, 9, etc. The latest is MPEG-21 of the 21st century. MPEG-3 the HD specifications was initiated, but was eventually combined with MPEG-2. Proposals for 5 (serial), 6 (even number, since 3 failed), 8 (powers of 2) were made, and 7 was chosen 😛 Ask Chiari Glione why!