SMPTE 325M-1999

This standard defines the flow control protocol to be used between an emission multiplexer and data server for opportunistic data broadcast. Opportunistic data broadcast inserts data packets into the output multiplex to fill any available free bandwidth. The emission mutliplexer maintains a buffer from which it draws data to be inserted. The multiplexer will request additional MPEG-2 transport packets from the data server as its buffer becomes depleted. The number of packets requested depends upon the implementation, with the most stringent requirement being requesting a single MPEG-2 transport packet where the request and delivery can occur in less than the emission time of an MPEG-2 transport packet from the multiplexer. This protocol is designed to be extensible and provide a basis for low-latency, real-time backchannel communications from the emission multiplexer.