3.3.5.5.3 License Management for Copy-Never Content
In some cases, the desired policy (1) is that content be usable by a receiver only for a limited time. In these cases, the transmitter MUST use a license that expires. Accordingly, access to the license will expire at the expiration time. This has the same effect as a policy in which the content expires after it is delivered to the receiver. For example, if a license is set to expire in 90 minutes, any content sent 30 minutes after the license has been sent will not be viewable for the full length of the content (90 minutes).
To address this issue, transmitters MUST create new licenses so that content being transmitted will not prematurely expire due to license expiration. For example, if a transmitter sent 90 minutes of Copy-Never broadcast content, it would issue a new license set to expire in 90 minutes to the receiver. License derivation data messages with new base counters will then be sent to the receiver every 9 minutes.