It has always been a point of pride for MPEG to have been able to create the MPEG-1 Audio-Video-Systems package overcoming the informal, but nonetheless effective barriers that used to separate video coding people, audio coding people and those more “engineering minded” that MPEG calls “systems people”. This “package approach” continued with MPEG-2, MPEG-4 and MPEG-7.
The arrival of the AVC standard, disconnected from an audio component and without a specific systems layer – but actually connectable with any audio and usable in MPEG-2 TS and IP – and the appearance of new systems layer technologies and audio compression ideas led to a decision of establishing 3 new “containers” of systems, video and audio standards. the 3 containers were nicknamed MPEG-B (Systems), MPEG-C (Video) and MPEG-D (Audio).
The MPEG-B container has been the place where some significant technologies have been developed (11 active parts). MPEG-C has a more reduced number of components (5), as AVC and later HEVC have included most technologies. MPEG-D has been the place where all new audio coding technologies not related to AAC have been developed until the appearance of 3D Audio.