ISO/IEC 29341-4-4:2011

Information technology - UPnP Device Architecture - Part 4-4: Audio Video Device Control Protocol - Level 2 - Audio Video Data Structures

ISO/IEC 29341-4-4:2011(E) defines the layout of the AV Datastructure Template (AVDT) XML document. An AVDT document describes the format requirements and restrictions of various data structures used within the UPnP AV specifications. Its purpose is to enable each device to describe (at run-time) its particular variation of these AV data structures. AVDT documents allow users of AV data structures (e.g. UPnP control points) to reduce the number of instances of those data structures that comply with the service specification but are not compatible with the device's particular capabilities. The ultimate goal of an AVDT document is to reduce those error conditions that are caused by control points creating instances of a data structure that exceed the static (known) capabilities of the device. Unfortunately, the AVDT mechanism will never eliminate all preventable error conditions, but it will help to reduce them by giving the client more information about the device's particular capabilities. This International Standard replaces ISO/IEC 29341-4-4, first edition, published in 2008, and constitutes a technical revision.

General Information

• Status: Published
• Publication Date: 14-Sep-2011
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: ISO/IEC JTC 1 - Information technology
• Current Stage: PPUB - Publication issued
• Start Date: 31-Jan-2012
• Completion Date: 14-Sep-2011

Relations

• Revises: ISO/IEC 29341-4-4:2008 - Information technology - UPnP Device Architecture - Part 4-4: Audio Video Device Control Protocol - Level 2 - Audio Video Data Structures
• Effective Date: 05-Sep-2023

Standards Content (Sample)

ISO/IEC 29341-4-4
Edition 2.0 2011-09
INTERNATIONAL
STANDARD
colour
inside
Information technology – UPnP device architecture –
Part 4-4: Audio Video Device Control Protocol – Level 2 – Audio Video Data
Structures
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ISO/IEC 29341-4-4
Edition 2.0 2011-09
INTERNATIONAL
STANDARD
colour
inside
Information technology – UPnP device architecture –
Part 4-4: Audio Video Device Control Protocol – Level 2 – Audio Video Data
Structures
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
L
ICS 35.200 ISBN 978-2-88912-679-8

29341-4-4 © ISO/IEC:2011(E)
CONTENTS
1  Overview and Scope . 2
1.1  Introduction . 2
1.2  Notation . 3
1.2.1  Data Types . 4
1.2.2  Strings Embedded in Other Strings . 4
1.2.3  Extended Backus-Naur Form . 4
1.3  Derived Data Types . 5
1.3.1  Comma Separated Value (CSV) Lists . 5
1.4  Management of XML Namespaces in Standardized DCPs . 6
1.4.1  Namespace Prefix Requirements . 9
1.4.2  Namespace Names, Namespace Versioning and Schema Versioning . 10
1.4.3  Namespace Usage Examples . 12
1.5  Vendor-defined Extensions . 13
1.5.1  Vendor-defined Action Names . 13
1.5.2  Vendor-defined State Variable Names . 13
1.5.3  Vendor-defined XML Elements and attributes . 13
1.5.4  Vendor-defined Property Names . 13
1.6  References . 13
2  AV Datastructure Template . 17
3  AV Datastructure Schema . 23

Figure 1: Typical Usage of AVDT . 3

Table 1-1 — EBNF Operators . 5
Table 1-2 — CSV Examples . 6
Table 1-3 — Namespace Definitions . 8
Table 1-4 — Schema-related Information . 9
Table 1-5 — Default Namespaces for the AV Specifications . 10

29341-4-4 © ISO/IEC:2011(E)
INFORMATION TECHNOLOGY –
UPNP DEVICE ARCHITECTURE –
Part 4-4: Audio Video Device Control Protocol –
Level 2 – Audio Video Data Structures
FOREWORD
1) ISO (International Organization for Standardization) and IEC (International Electrotechnical Commission) form the
specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in
the development of International Standards. Their preparation is entrusted to technical committees; any ISO and
IEC member body interested in the subject dealt with may participate in this preparatory work. International
governmental and non-governmental organizations liaising with ISO and IEC also participate in this preparation.
2) In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
3) The formal decisions or agreements of IEC and ISO on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested IEC and ISO member bodies.
4) IEC, ISO and ISO/IEC publications have the form of recommendations for international use and are accepted
by IEC and ISO member bodies in that sense. While all reasonable efforts are made to ensure that the
technical content of IEC, ISO and ISO/IEC publications is accurate, IEC or ISO cannot be held responsible for
the way in which they are used or for any misinterpretation by any end user.
5) In order to promote international uniformity, IEC and ISO member bodies undertake to apply IEC, ISO and
ISO/IEC publications transparently to the maximum extent possible in their national and regional publications.
Any divergence between any ISO/IEC publication and the corresponding national or regional publication
should be clearly indicated in the latter.
6) ISO and IEC provide no marking procedure to indicate their approval and cannot be rendered responsible for
any equipment declared to be in conformity with an ISO/IEC publication.
7) All users should ensure that they have the latest edition of this publication.
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9) Attention is drawn to the normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
10) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
International Standard ISO/IEC 29341-4-4 was prepared by UPnP Forum Steering
committee , was adopted, under the fast track procedure, by subcommittee 25:
Interconnection of information technology equipment, of ISO/IEC joint technical committee 1:
Information technology.
This International Standard replaces ISO/IEC 29341-4-4, first edition, published in 2008, and
constitutes a technical revision.
The list of all currently available parts of the ISO/IEC 29341 series, under the general title
Information technology – UPnP device architecture, can be found on the IEC web site.
This International Standard has been approved by vote of the member bodies, and the voting
results may be obtained from the address given on the second title page.
—————————
rd
UPnP Forum Steering committee, UPnP Forum, 3855 SW 153 Drive, Beaverton, Oregon 97006 USA. See also
“Introduction”.
29341-4-4 © ISO/IEC:2011(E)
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

XXXX: © IEC:2010 — 2 — 29341-4-4 © ISO/IEC:2011(E)
1 Overview and Scope
1.1 Introduction
This document defines the layout of the AV Datastructure Template (AVDT) XML document.
An AVDT document describes the format requirements and restrictions of various data
structures used within the UPnP AV specifications. Although these data structures are
defined very precisely in the appropriate service specification, in most cases, each data
structure definition allows for a certain degree of variation in order to accommodate
differences between individual devices.
The purpose of an AVDT document is to enable each device to describe (at run-time) its
particular variation of these AV data structures. AVDT documents allow users of AV data
structures (e.g. UPnP control points) to reduce the number of instances of those data
structures that comply with the service specification but are not compatible with the device’s
particular capabilities. The ultimate goal of an AVDT document is to reduce those error
conditions that are caused by control points creating instances of a data structure that
exceed the static (known) capabilities of the device. Unfortunately, the AVDT mechanism will
never eliminate all preventable error conditions, but it will help to reduce them by giving the
client more information about the device’s particular capabilities.
As described above, an AVDT document is a machine readable, implementation-specific
variant of an AV data structure defined by one of the UPnP AV specifications. For a given
device, each instance of that data structure must conform to both the specification definition
AND the device’s AVDT definition of that data structure.
Ironically, an AVDT document is both a more-restrictive and more-permissive variant of the
specification definition. AVDT documents are more restrictive because they limit certain
aspects of the data structure (e.g. such as the allowed values for each field) that are
otherwise permitted by the specification definition. However, due to limitations of the AVDT
constructs, it is simply not possible to express some of the more intricate requirements
defined by the specification (e.g. subtle interdependencies between data structure fields).
Consequently, instances of a data structure that comply with a given AVDT description may
not fully comply with all of the requirements defined in the specification.
The types of data structures that can be described by an AVDT document represent a (non-
hierarchitical) set of named property values. The set of allowed property names and their
allowed values for a given data structure are defined by one of the UPnP AV specifications.
Individual instances of these data structures are manifested via an XML document whose
elements and attributes correspond to the set of named properties. In other words, within the
XML document that corresponds to a given instance of a certain data structure, each XML
element and attribute contains the value of a specific named property.
An AVDT document is conceptually similar to an XML schema in that both entities identify the
XML elements and attributes that appear in any given document instance. Additionally, both
AVDT documents and XML schemas identify the allowed values that are permitted for each
element and/or attribute which corresponds to a specific property. However, unlike an XML
schema, an AVDT document can also identify certain dependencies between two or more
properties. For example, the set of allowed values of one property may depend on the actual
value of another property. This type of interrelationship is difficult to represent using an XML
schema. Hence, the AVDTdocument structure is needed.
In the various AV Architecture scenarios, sometimes there is a need to exchange device
capabilities to ensure high level interoperability. In order to express the parameterized
capability, an AV specification defines various templates for each purpose. A device uses the
template and populates it with values to reflect its capabilities at run-time.

29341-4-4 XXXX: © IEC:2010 © ISO/IEC:2011(E) — 3 —
The AV Datastructure Template (AVDT) is a common structure to define various templates,
which are called “Datastructure”. This is written in XML and each data structure
...