Question: In a PSS stream utilizing content encryption with a single key, as per specifications, what should a client assume if no key stream is signaled in the Session Description Protocol (SDP) for a media stream?
Option 1: The client should request a key stream via a separate DRM system.
Option 2: The client should use a default key predefined by the device manufacturer.
Option 3: The client should reject the media stream due to security concerns.
Option 4: The client should assume direct encryption with a single content key is used.
Explanation: According to specifications, if no key stream is signaled in the SDP for a media stream, the client is mandated to assume that direct encryption with a single content key is utilized, ensuring seamless and secure playback without additional overhead.