TABLE OF CONTENTS Jerry C. Whitaker, Editor-in-Chief
The discussion of facility design given in Chapter 9.4 applies in general to any communications center. There are a number of areas, however, where the special requirements of video must be considered. Furthermore, the changing nature of the digital video production/transmission plant demands a level of operational flexibility never before required or realized.
The transition from a conventional NTSC plant to DTV is dictated by any number of factors, depending upon the dynamics of a particular facility. The choices, however, usually can be divided into four overall groups [1]:
Simple pass-through
Pass-through with limited local insert
Local HDTV production
Multicasting
The intent of this scenario is to simply pass through network DTV programming. Important capabilities that are missing include:
No local identity
No local value added
Little revenue potential from the DTV service
The intent here is to pass through network DTV programming and, additionally, facilitate the following capabilities:
Local insertion of interstitials, promotional announcements, and commercials
Local insertion of full-screen logos
Network delay and program time shifting
Insertion of local 525 programming
Significant drawbacks to this approach include the following:
Insertion capabilities are limited
The bit-stream splicer cannot switch on every frame
Network contributions must be processed to include splice points
To keep costs down, local insert material probably would be precompressed off-site, not live
The basic capabilities...
