Question: In MBMS (Multimedia Broadcast/Multicast Service) streaming with Forward Error Correction (FEC), what is a requirement for a receiver to perform FEC decoding to cover packet losses when multiple user services are bundled together?
Option 1: The receiver only needs to receive the FEC repair stream and the currently played out service's flows.
Option 2: The receiver must receive all flows indicated as FEC source packets, regardless of the service being played out, but not necessarily the FEC repair stream.
Option 3: The receiver can choose which flows to receive for FEC decoding based on current playback services.
Option 4: The receiver shall receive all flows indicated to be sent as FEC source packets, even if the flows are in a service currently not played out, and also receive the FEC repair stream.
Explanation: For effective FEC decoding to cover packet losses in an MBMS streaming context where multiple user services are bundled, a receiver must have all necessary components. This includes receiving all flows marked for FEC, regardless of their association with currently played out services (to ensure comprehensive error correction across the bundle), and also receiving the dedicated FEC repair stream designed to facilitate this error correction process. This ensures that the receiver can adequately reconstruct any lost packets across all bundled services.