Question: In a PSS (Packet-switched Streaming Service) scenario, when a UE (User Equipment) wants to switch to new content for which it already has the SDP (Session Description Protocol) file, what header field must the client add to the SP PLAY method request to specify the media control URIs of the new streams?
Option 1: Require header with "3gpp-switch" feature tag
Option 2: Switch-Stream header field with the new stream’s media control URIs
Option 3: Supported header with "3gpp-switch" in the request body
Option 4: If-Match header with the entity-tag value for SDP validation
Explanation: When switching to new content with an available SDP, the PSS client must inform the server about the media control URIs of the new streams. This is specifically done by adding the Switch-Stream header field to the SP PLAY method request, which contains the necessary URI information for the switch, ensuring a seamless transition between streamed contents.