White Paper WHP 297 Download
Television production and broadcast facilities currently use specialised point-to-point unidirectional links to transport real-time video and audio synchronously around the plant. Broadcast industry interest in replacing this specialised infrastructure with an Internet Protocol based solution has been gathering pace in recent times, driven by economic and technical considerations.
IP networks offer a bidirectional layered communications model. Data is moved across the network in packets. Moving audio and video over an IP network involves splitting the signals into packets, separating the data from its timing signal. This is a fundamentally different paradigm to the prevailing synchronous technology, which requires a fresh approach to timing and synchronisation in particular.
This paper proposes an approach to timing and synchronisation of real-time video and audio of modelling these signals as a series of Events to which timestamps sampled from a high-resolution clock are bound. The clock is distributed to all devices using IEEE 1588 Precision Time Protocol (PTP). Events can be periodic or aperiodic within a series, comprising raw or compressed audio or video, or any other arbitrary time-related data. While certain aspects of this approach are novel, the principles on which it is based draw heavily on recent work in SMPTE and AES concerning timing and synchronisation in networked environments.
This publication is part of the Automated Production and Media Management section