SMPTE ST 430-14 PDF

This document specifies (i) a Transfer Protocol that allows Data Items from an Aux Data Track File to be transmitted to a Processor for reproduction, and (ii) a Synchronization Signal that allows a Processor to reproduce Data Items synchronously with the D-Cinema presentation. The Transfer Protocol uses the Hypertext Transfer Protocol (HTTP), while the Synchronization Signal is a binary signal that is accurate to the nearest audio sample of the presentation, intended to be generated by the Image Media Block at time of playback, and for use with AES3 interfaces.

While the Transfer Protocol requires the presence of the Synchronization Signal, the Synchronization Signal can be used in absence of the Transfer Protocol.