AN377 Datasheet, PDF (1/18 Pages) Silicon Laboratories – TIMING AND SYNCHRONIZATION IN BROADCAST VIDEO

AN377
TIMING AND SYNCHRONIZATION IN BROADCAST VIDEO
1. Introduction
Digitization of video signals has been common practice in broadcast video for many years. Early digital video was
commonly encoded on a 10-bit parallel bus, but as higher processing speeds became practical, a serial form of the
digitized video signal called the Serial Digital Interface (SDI) was developed and standardized. Serialization of the
digital video stream greatly facilitates its distribution within a professional broadcast studio.
Master Sync Generator
On-site
Video Cameras
Sync
(Genlock)
Video Server
(Mass Storage)
SDI
Distribution
Amplifier
SDI SDI
SDI
Video
Switching/
Processing
SDI
SDI
SDI
SDI
Frame
Synchronizer
Professional
Monitor
Video Server
(Storage)
SDI
Video
Router
Remote
Video Camera
Transmission
Facility
Figure 1. Typical Example of a Professional Broadcast Video
In a studio with multiple cameras, it is important that video signals coming from multiple sources are frame aligned
or synchronized to allow seamless switching between video sources. For this reason, a synchronization signal is
often distributed to all video sources using a master synchronization generator as shown in Figure 1. This allows
video switching equipment to select between multiple sources without having to buffer and re-synchronize all of its
input video signals. In this application note, we will take a closer look at the various components that make up a
broadcast video system and how each of the components play a role in the synchronization chain.
Rev. 0.1 8/09
Copyright © 2009 by Silicon Laboratories
AN377