Optionally specifies the key ID for the given key. This is needed in multi-key scenarios as it allows the player to select the correct key when audio/video tracks are encrypted with different keys.
Key ID. Optional if the same kid is used for the whole content (every audio and video track of
each representation). Otherwise the player won’t know which kid has to be used.
Defines a decryption key.
Optionally specifies the key ID for the given key. This is needed in multi-key scenarios as it allows the player to select the correct key when audio/video tracks are encrypted with different keys.