AVContentKeySession and AirPlay

When playing an HLS stream with an AVPlayer object, where the content key was retrieved using an AVAssetResourceLoaderDelegate object, the AirPlay functionality works out-of-box. The same cannot be said when the content key for the stream was retrieved using an AVContentKeySessionDelegate. When enabling AirPlay, I've noticed that AVContentKeySessionDelegate.contentKeySession(_:didProvide:)

gets called, where a new content key is retrieved from the KSM. Even with the new content key, the stream will not start on the AirPlay device (Apple TV). How can this issue be resolved?

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It may be because AirPlay doesn't allow you to use a persistent key. You have to check the canProvidePersistableContentKey property on AVContentKeyRequest, and/or check if it's an instance of AVPersistableContentKeyRequest, and if not, fetch a new key from the key server instead of using a previously downloaded persistent key. In AVAssetResourceLoaderDelegate-land, this was accomplished by checking if AVAssetResourceLoadingRequest's allowedContentTypes property (an array) contained AVStreamingKeyDeliveryPersistentContentKeyType.


Also, try setting allowsExternalPlayback on your AVPlayer instance to NO. From my conversation with some AVFoundation engineers at WWDC 2018, this means that the audio will be streamed to the origin device, decrypted, re-encrypted, and re-streamed to the target device. I think this actually means you *can* use persistent keys for AirPlay. It also fixes an unrelated issue where old AppleTV hardware can't change playback speed.

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Mr. Jefferson
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