Introduction

Thank you for choosing the Stagebox camera back media streaming device. With Stagebox you will realise considerably more efficient workflows and significantly reduce the CAPEX and OPEX of high quality productions. Stagebox with its easy interface, total connectivity and genlock over IP capability, provides you with a complete solution for broadcasting over IP networks.

Stagebox concept

Stagebox has been developed as a simple means of providing television production connectivity over Ethernet. The Stagebox unit includes all the conversions necessary between industry standard video, audio, time code, sync and control signals and standard packet-based IP networks, providing full studio camera connectivity through a single Cat5e/6 cable. This has the potential to revolutionise studio and outside broadcast production methods by substituting low-cost network equipment for the dedicated infrastructure of the professional television studio or outside broadcast environment. This has prospective advantages both in reducing costs and providing increased flexibility in television production methods.

Stagebox Timing and Synchronisation

A key feature of Stagebox which distinguishes it from other Video over IP products is its ability to handle timing over the network using standart IT infrastructure. In a Stagebox network Genlock and Time Code inputs and outputs are available and work just as you would expect in a traditional broadcast system interfacing to SDI.

Along with reliable high quality video and audio, one of the most significant challenges that commodity IT systems bring to broadcasting is the lack of synchronous signals which are essential for any multi-camera production. These synchronous signals are presented to cameras in the form of Genlock.

In addition to a synchronous signal, time information is needed. Traditionally called “Timecode”, this is a temporal reference to a frame of video, or sample of sound and is often carried within an SDI video signal. Broadcast Systems need these signals to manage multiple video and audio sources and they are used extensively in live and post-production.

The generation of a synchronous signal over an IP Network is based on Precision Time Protocol (PTP). PTP is a common timing standard within IP networks and has a number of professional applications and features that make it attractive to broadcasters.

PTP is based on Layer 2 (Local Area Networks) and requires the Stageboxes and other PTP enabled devices to analyse time stamped packets to determine the mean-path delay across any given network, at any given time. From this it is able to steer a series of oscillators to generate a ‘locked’ synchronous signal.

Not only does this lock allow a common sync pulse to be generated, but it also carries temporal information, and so a common timecode is carried across a network. By time stamping all the video and audio packets in a network with this common timecode, Stagebox is able to achieve an accurate relationship between the video and audio.