3.2.5.3 Receiving a GetContentInfo Request
The server MUST first follow the steps as specified in section 3.2.5.1.
The server MUST check with the higher layer that the URL that the client specified in the request is valid. If it is not valid, this is an error, and the server MUST respond with some suitable RTSP error status code (as specified in [RFC2326] 7.1.1), such as 404.
The GetContentInfo request does not require any server state. Hence, if the Session header is missing, this MUST NOT be treated as an error.
The GetContentInfo response MUST follow the rules as specified in sections 3.2.5.2 and 2.2.7.4.