Premium content has different track types: SD, HD, UHD, audio, 3D etc. Content owners want different content protection policies applied to each.
Accordingly, it follows that a specific device may be able to only play back a subset of the tracks present in a media presentation. It is important that players be able to handle such situations.
The authoritative source for evaluating the policy to be applied is the DRM system on the client. It receives the policy in the license that carries the content key. To apply different policies to different tracks, they are encrypted with different keys, potentially delivered in different licenses that may have different policies embedded.
Therefore it may be that the client makes a request for one or more licenses for one or more keys, receives some set of licenses (perhaps not containing keys for all tracks!), tries to use them but finds that the DRM system rejects playback of the UHD track (due to policy check failure). A player needs to understand that this does not necessarily mean a fatal error but that it should simply exclude the UHD track from playback.
Application developers also need to consider how to communicate such policy-derived actions to users.
Premium content has different track types: SD, HD, UHD, audio, 3D etc. Content owners want different content protection policies applied to each.
Accordingly, it follows that a specific device may be able to only play back a subset of the tracks present in a media presentation. It is important that players be able to handle such situations.
The authoritative source for evaluating the policy to be applied is the DRM system on the client. It receives the policy in the license that carries the content key. To apply different policies to different tracks, they are encrypted with different keys, potentially delivered in different licenses that may have different policies embedded.
Therefore it may be that the client makes a request for one or more licenses for one or more keys, receives some set of licenses (perhaps not containing keys for all tracks!), tries to use them but finds that the DRM system rejects playback of the UHD track (due to policy check failure). A player needs to understand that this does not necessarily mean a fatal error but that it should simply exclude the UHD track from playback.
Application developers also need to consider how to communicate such policy-derived actions to users.