3.1.5.7 Receiving a $M (Metadata) Packet
The client MUST verify that the $M packet adheres to the syntax specified in section 2.2.3.6.
If the AFFlags field in the MMS data packet (section 2.2.3.1.2) specifies that the metadata is being transmitted as multiple $M packets, and this is not the last $M packet, then the client MUST set the value of the Expected-Packets variable to $M and process the rules in section 3.1.5.2.
When the last $M packet has been received, the payloads in each $M packet MUST be reassembled before processing can continue.
The client MUST set the Playlist-gen-id variable in the abstract data model to the value specified by the playlist-gen-id field in the $M packet.
The client SHOULD make the metadata available to a higher layer.
After having received the last $M packet, the client MUST set the value of the Expected-Packets variable to $H and then process the rules in section 3.1.5.2.