Information AboutMpeg-4 |
| CATEGORIES ABOUT MPEG-4 | |
| audio codecs | |
| video codecs | |
| mpeg | |
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MPEG-4 absorbs many of the features of MPEG-1 and MPEG-2 and other related standards, adding new features such as (extended) VRML support for 3D rendering, Object -oriented composite files (including audio, video and VRML objects), support for externally-specified Digital Rights Management and various types of interactivity. AAC (Advanced Audio Codec) was standardized as an adjunct to MPEG-2 (as Part 7) before MPEG-4 was issued. Most of the features included in MPEG-4 are left to individual Developer s to decide whether to implement them. This means that there are probably no complete implementations of the entire MPEG-4 set of standards. To deal with this, the standard includes the concept of "profiles" and "levels", allowing a specific set of capabilities to be defined in a manner appropriate for a subset of applications. The primary MPEG-4 audio codec, AAC is decoded/played by Apple's IPod product line. Two video Codecs included in MPEG-4, Simple Profile (SP) and Advanced Video Codec AVC , are decoded/played by the 5th Generation iPod (AKA the " Video IPod "). However, neither the iPod nor Apple's Quicktime Player are fully MPEG-4 compliant decoders, as they do not natively support many of the required parts of the standard. MPEG-4 PARTS MPEG-4 consists of several standards—termed "parts"—including the following:
Profiles are also defined within the individual "parts", so an implementation of a part is ordinarily not an implementation of an entire part. MPEG-1 , MPEG-2 , MPEG-7 and MPEG-21 are other suites of MPEG standards. LICENSING MPEG-4 is patented proprietary technology. This means that, although the software to create and play back MPEG-4 videos may be readily available, a licence is needed to use it legally. Patents covering MPEG-4 are claimed by over two dozen companies. There is no simple way to license MPEG-4, but the MPEG Licensing Authority MPEG Licensing Authority can license patents required for MPEG-4 visual techniques from a wide range of companies (audio is licensed separately). A one stop shop is currently not possible; these articles engadget.com article theinquirer.net article pcmag.com article claim that AT&T is suing companies such as Apple over alleged MPEG-4 patent infringement. This AT&T action against Apple illustrates that it is hard to know which companies have patents covering MPEG-4. EXTERNAL LINKS Links from the main article Other links
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