The confusion comes from the fact that other servers currently implementing Dolby Atmos (Dolby and Doremi servers) are ‘still’ using a single KDM system for both IMB and Immersive Sound external renderer. This was originally a proprietary solution, waiting for DCI to come with a specification on multi-media block (MMB) architecture, mainly targeting the outboard media blocks (OMB) designed for processing object-based sound (OBAE).
Since September 2014, DCI specs (DCSS) have been updated to include MMB architecture, including the specification for multiple KDMs feature (see http://dcimovies.com/specification/index.html ):
Extract from DCSS Chapter 9:
MMB is operationally supported as follows:
• Each participating MB/SM shall be provided with the CPL and a KDM for each composition of the Show Playlist (SPL). Each KDM shall be created (encrypted) uniquely for the MB/SM it is targeted for, and each KDM shall carry all the CPL identified essence keys required for the composition.
Barco started the integration of Dolby Atmos in the ICMP after the new DCSS has been released, using the new Dolby protocol implementing that new specification. Barco is the first to use the new multiple KDM DCI-compliant approach. It is expected that this will become an strict obligation for all servers in the future.
For a dual KDM DCI-compliant solution, KDM Labs will need 2 certificates (one from IMB and one from OMB (CP850)) to generate 2 KDMs (one for each device). Both certificates can be retreived from the ICMP Web Commander user interface.
