Profiles and levels in MPEG-4: Approach and overview

摘要

Profiles and levels in MPEG-4 are standardised in order to give users a number of well-defined and well-chosen conformance points. They serve two main purposes: (1) ensuring interoperability between MPEG-4 implementations, and (2) allowing conformance to the standard to be tested. Profiles exist not only for the Audio and Visual parts of the standard (audio profiles and visual profiles), but also for the Systems part of the standard, in the form of graphics profiles, scene graph profiles, and an object descriptor profile. Different profiles are created for different application environments. The policy for defining profiles is that they should enable as many applications as possible while keeping the number of different profiles low. MPEG has defined a first set of profiles for MPEG-4, but more are expected. MPEG will be restrictive in defining any new profiles, listening carefully to what its users have to say.