Patent ID: 8462856

Claim:
A system for media communications between a transmitting endpoint or server and one or more receiving endpoint(s) or server(s) over a packet-based communication network, the system comprising: an encoder configured to use a threaded coding structure having a number of different layers including a lowest temporal layer, wherein each picture is associated with a picture index number; wherein data corresponding to a single picture is portioned and transmitted in one or more individual data packets, wherein an individual data packet comprises data elements that indicate: for the lowest temporal layer pictures, a sequence number identifying said pictures, for other temporal layer pictures, a reference to the sequence number of the most recent, in decoding order, lowest temporal layer picture, and for all pictures, a ‘start’ flag and an ‘end’ flag that respectively indicate if the individual data packet contains the first or last data portions of the picture, so that a receiving endpoint or server on receipt of the individual data packet can detect a loss of portions of a lowest temporal layer picture by examining if all data portions of the picture corresponding to the referenced picture index have been received at the receiving endpoint or server such that their packet sequence numbers contain no gaps, and where the first such data portion has the ‘start’ bit set and the last such data portion has the ‘end’ bit set.