Texas Instruments H.264 High Profile Encoder, Руководство пользователя

Страница: 15 / 139

Introduction
1-3

process()
The
control()
API provides a standard way to control an algorithm instance and receive status
information from the algorithm in real-time. The
control()
API replaces the
algControl()
API
defined as part of the IALG interface. The
process()
API does the basic processing
(encode/decode) of data.
Apart from defining standardized APIs for multimedia codecs, XDM also standardizes the generic
parameters that the client application must pass to these APIs. The client application can define
additional implementation specific parameters using extended data structures.
The following figure depicts the XDM interface to the client application.
As depicted in Figure 1-1 , XDM is an extension to XDAIS and forms an interface between the client
application and the codec component. XDM insulates the client application from component-level
changes. Since TI’s multimedia algorithms are XDM compliant, it provides you with the flexibility to
use any TI algorithm without changing the client application code. For example, if you have
developed a client application using an XDM-compliant MPEG4 video decoder, then you can easily
replace MPEG4 with another XDM-compliant video decoder, say H.263, with minimal changes to
the client application.
For more details, see eXpressDSP Digital Media (XDM) Standard API Reference (literature number
SPRUEC8).
1.1.3 IRES Overview
IRES is a generic, resource-agnostic, extendible resource query, initialization and activation
interface. The application framework defines, implements, and supports concrete resource
interfaces in the form of IRES extensions. Each algorithm implements the generic IRES interface, to
request one or more concrete IRES resources. IRES defines standard interface functions that the
framework uses to query, initialize, activate/deactivate and reallocate concrete IRES resources. To
create an algorithm instance within an application framework, the algorithm and the application
framework agrees on the concrete IRES resource types that are requested. The framework calls
the IRES interface functions, in addition to the IALG functions, to perform IRES resource
initialization, activation, and deactivation.
Client Application
XDAIS Interface (IALG)
TI’s Codec Algorithms
XDM Interface
Figure 1-1 XDM Introduction