We are developing a video streaming app that uses AVContentKeySession with FairPlay Streaming. Our implementation supports both online playback (non-persistable keys) and offline playback (persistable keys).
We have observed the following behavior:
Once a content key has been obtained for a given Content Key ID, AVContentKeySession does not trigger contentKeySession(_:didProvide:) again for that same Key ID
We also attempted to explicitly call processContentKeyRequest(withIdentifier:initializationData:options:) on the session to force a new key request for the same identifier, but this did not result in the delegate callback being fired again. The session appears to consider the key already resolved and silently ignores the request.
This means that if a user first plays content online (receiving a non-persistable key), and later wants to download the same content for offline use (requiring a persistable key), the delegate callback is not fired again, and we have no opportunity to request a persistable key.
Questions
-
Is this the expected behavior? Specifically, is it by design that
AVContentKeySessioncaches the key for a given Key ID and does not re-request it — even whenprocessContentKeyRequest(withIdentifier:)is explicitly called? -
Should we use distinct Content Key IDs for persistable vs. non-persistable keys? For example, if the same piece of content can be played both online and offline, is the recommended approach to have the server provide different
EXT-X-KEYURIs (and thus different key identifiers) for the streaming and download variants? -
Is there a supported way to force a fresh key request for a Key ID that has already been resolved — for example, to upgrade from a non-persistable to a persistable key?
Environment
- iOS 18+
AVContentKeySession(keySystem: .fairPlayStreaming)
Any guidance on the recommended approach for supporting both streaming and offline playback for the same content would be greatly appreciated.