MCAPI Support for MPEG CMAF Supplemental Data

[johnsim]

CMAF Amendment 2 introduces the notion of Supplemental data brands, indicating the presence of additional information in a track that is not required to render playback of the track – e.g. NAL units or SEI messages. Two examples: ‘ccac’ indicating that 608/708 captioning is present, or another 4CC indicating SEI delivered dynamic HDR metadata which can be applied to an underlying 10-bit CMAF video profile.

A device may support all of the media profiles but only be able to handle the supplemental data present in one specific media profile, but not others. An web app needs to be able to ask the UA “do you support this supplemental data applied to this media profile?” This requirement is similar to encryption mode, where the app needs to ask MCAPI “do you support this encryption mode applied to this media profile?”