ITU-R REPORT BT.1223 PDF

Introduction

A description of the basic functions of a television information transfer may be performed in terms of a layered architecture complying with the one defined by ISO and CCITT in the OSI framework [Miceli, 1986; Fierro and Miceli, 1987]. Such an approach may be helpful also in the future, when television signals are going to be transmitted across a broadband ISDN. Furthermore it allows a clear separation of the various problems concerning the definition of a new standard. In particular the information path from the 7th layer to the first may be considered also as an ordered way to face these problems.

In Figure 1, the information transfer at a television interconnection is symbolically expressed in terms of the layered architecture.

This has to be considered as a tentative solution to the problem of putting typical television signals into the abstracted functions of the ISO model.

Particularly, problems may arise as far as the 5th layer is concerned, because it is not totally clear whether the "picture rate" and the "pictures per frame" may be considered at the 5th or as a sub-layer of the 6th level. However, this is a theoretical problem only; what is important is the order or, in other words, the priority of the various functions in the television interconnection. For this purpose a valid assignment of parameters is given in Figure 1.