Key rotation

Key rotation for live streams is where a live stream encryption key changes periodically, and a new key needs to be fetched. No additional APIs are required for this feature, although there may be a slight pause in playback when key rotation occurs.

Depending on the licence server used, the default OTVHttpMediaDrmCallback class may not be able to handle key rotation requests if, for example, a new token is required for each key request. In that case, a bespoke class implementing OTVMediaDrmCallback may be needed instead. See the supplied example code (customised-encrypted-playback) for an example with a dedicated OTVCustomisedMediaDrmCallback class.

Key rotation and temporal licence pre-delivery

To reduce key request calls to the licence server when playing a stream with key rotation, the licence server may send back the key for the next session and keys for the sessions following. SDK 5 caches these additional keys, and when a new key is required, the player checks if the key is already cached before submitting a request to the licence server. There is no additional API for this feature.

Storing pre-delivered keys is not supported for API levels below 23 (Marshmallow).