1、 Copyright 2011 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue., White Plains, NY 10601 (914) 761-1100 Approved April 15, 2011 Table of Contents Page Foreword . 2 Intellectual Property 2 Introduction 2 1 Scope . 3 2 Conformance Notation . 3 3 Normative References . 3 4 Def
2、inition of Acronyms, Terms and Data Types 4 5 General (Informative) 4 6 Generic Stream Partition for Text-Based Metadata . 5 6.1 Generic Stream Partition Pack . 5 6.2 Generic Stream Data Element Coding . 6 6.3 Generic Stream Constraints . 7 7 Descriptive Metadata Scheme and Sets for Text-Based Metad
3、ata . 7 7.1 Universal Label for Descriptive Metadata Scheme 7 7.2 Descriptive Metadata Set Definitions . 7 8 Guideline on Text-Based Metadata Implementation 10 8.1 Selection of Carriage Mechanism 10 8.2 Text-Based Metadata Identification . 11 8.3 Header Metadata Implementation (Informative) . 11 Ann
4、ex A Bibliography (Informative) . 14 Page 1 of 14 pages SMPTE RP 2057:2011 SMPTE RECOMMENDED PRACTICE Text-Based Metadata Carriage in MXF SMPTE RP 2057:2011 Page 2 of 14 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developin
5、g organization. Headquartered and incorporated in the United States of America, SMPTE has members in over 80 countries on six continents. SMPTEs Engineering Documents, including Standards, Recommended Practices, and Engineering Guidelines, are prepared by SMPTEs Technology Committees. Participation
6、in these Committees is open to all with a bona fide interest in their work. SMPTE cooperates closely with other standards-developing organizations, including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in Part XIII of its Administrative Practices. SMP
7、TE RP 2057 was prepared by Technology Committee 31FS. Intellectual Property At the time of publication no notice had been received by SMPTE claiming patent rights essential to the implementation of this Standard. However, attention is drawn to the possibility that some of the elements of this docume
8、nt may be the subject of patent rights. SMPTE shall not be held responsible for identifying any or all such patent rights. Introduction This section is entirely informative and does not form an integral part of this Engineering Document. This document addresses a requirement for carrying text-based
9、metadata with a specified text MIME type encoded using either Unicode UTF-8 or UTF-16 character encoding (such as XML) as it is in a MXF file without encoding each element using the KLV Packet. Text-based metadata can be encapsulated in an MXF file using the following methods as described in the res
10、t of this introduction. Text-based metadata can be carried using the Generic Stream Container defined in SMPTE ST 410. SMPTE ST 410 was developed to give a mechanism to carry either essence or metadata that cannot suitably be stored in the Header Metadata in a MXF file body using the Generic Stream
11、Container. The essence is limited to lumpy essence that cannot be carried by the Generic Essence Container. The metadata would be bulky text data that cannot be carried by the Header Metadata. This document therefore specifies the mapping of text-based metadata into the Generic Stream Container alon
12、g with how to identify the Generic Stream Payload. It also includes the specification of the following requirements described in SMPTE ST 410: Specify the format and semantics of the Payload bytes. Specify a Universal Label to identify each payload. Define the mechanism used to link from the Header
13、Metadata to the Generic Stream Payload by use of the Generic Stream ID. Specify whether an index table is forbidden, optional or mandatory for the associated Generic Streams along with the format of the Index Table. Text-based metadata can be owned by a DM Framework as defined in SMPTE ST 377-1. In
14、this case, text-based metadata is encapsulated in the MXF Header Metadata using Descriptive Metadata Plug-In. SMPTE RP 2057:2011 Page 3 of 14 pages 1 Scope This document defines how to carry text-based metadata with a specified text MIME type encoded using either Unicode UTF-8 or UTF-16 character en
15、coding (such as XML) in a MXF file. This standard defines two methods of text-based metadata carriage. The first method is to carry text-based metadata using the MXF Generic Stream Partition defined in SMPTE ST 410. The second method is to carry it in the MXF Header Metadata by defining a DM Framewo
16、rk which includes Text-based Sets. This document specifies the Generic Stream Partition Pack for several text-based metadata formats including the KLV coding of the Generic Stream Data Element, and DM Schemes including DM Framework, Sets and Items for text-based metadata. 2 Conformance Notation Norm
17、ative text is text that describes elements of the design that are indispensable or contains the conformance language keywords: “shall“, “should“, or “may“. Informative text is text that is potentially helpful to the user, but not indispensable, and can be removed, changed, or added editorially witho
18、ut affecting interoperability. Informative text does not contain any conformance keywords. All text in this document is, by default, normative, except: the Introduction, any section explicitly labeled as “Informative“ or individual paragraphs that start with “Note:” The keywords “shall“ and “shall n
19、ot“ indicate requirements strictly to be followed in order to conform to the document and from which no deviation is permitted. The keywords, “should“ and “should not“ indicate that, among several possibilities, one is recommended as particularly suitable, without mentioning or excluding others; or
20、that a certain course of action is preferred but not necessarily required; or that (in the negative form) a certain possibility or course of action is deprecated but not prohibited. The keywords “may“ and “need not“ indicate courses of action permissible within the limits of the document. The keywor
21、d “reserved” indicates a provision that is not defined at this time, shall not be used, and may be defined in the future. The keyword “forbidden” indicates “reserved” and in addition indicates that the provision will never be defined in the future. A conformant implementation according to this docum
22、ent is one that includes all mandatory provisions (“shall“) and, if implemented, all recommended provisions (“should“) as described. A conformant implementation need not implement optional provisions (“may“) and need not implement them as described. Unless otherwise specified, the order of precedenc
23、e of the types of normative information in this document shall be as follows: Normative prose shall be the authoritative definition; Tables shall be next; followed by formal languages; then figures; and then any other language forms. 3 Normative References Note: All references in this document to ot
24、her SMPTE documents use the current numbering style (e.g. SMPTE ST 336:2007) although, during a transitional phase, the document as published (printed or PDF) may bear an older designation (such as SMPTE 336M-2007). Documents with the same root number (e.g. 336) and publication year (e.g. 2007) are
25、functionally identical. The following standards contain provisions which, through reference in this text, constitute provisions of this recommended practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this
26、recommended practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. SMPTE RP 2057:2011 Page 4 of 14 pages SMPTE ST 336:2007, Data Encoding Protocol Using Key-Length-Value SMPTE ST 377-1:2009, Material Exchange Format (MXF) File For
27、mat Specification SMPTE ST 395:2003, Television Metadata Groups Registry Structure SMPTE ST 400:2004, Television SMPTE Labels Structure SMPTE ST 410:2008, Material Exchange Format Generic Stream Partition RFC5646 Tags for Identifying Languages http:/www.iana.org/assignments/media-types/text, Public
28、Registry of Text MIME Types ISO/IEC 10646:2003, Information Technology Universal Multiple-Octet Coded Character Set (UCS) XML, Extensible Markup Language (XML) 1.0, W3C Recommendation XML, Extensible Markup Language (XML) 1.1, W3C Recommendation 4 Definition of Acronyms, Terms and Data Types For the
29、 purposes of this document, the terms and definitions given in SMPTE ST 377-1 and SMPTE ST 410 and the following apply. IANA: Internet Assigned Numbers Authority MIME: Multipurpose Internet Mail Extensions Text-based Metadata: Text data with a specified text MIME type registered in Public Registry o
30、f Text MIME Types, encoded using either Unicode UTF-8 or UTF-16 character encoding XML: Extensible Markup Language according to versions 1.0 or 1.1 of the W3C Recommendation 5 General (Informative) The MXF File Format specification standard, SMPTE ST 377-1, provides the Descriptive Metadata Plug-in
31、mechanism to carry additional Descriptive Metadata elements in the MXF Header Metadata. This document defines the DM Scheme including DM Framework, Sets and Items for Text-based Metadata with a specified text MIME type encoded using either Unicode UTF-8 or UTF-16 character encoding. The Text-based M
32、etadata may include Descriptive metadata or Application metadata. The Text-based Metadata is referenced from DM Tracks. The DM Tracks may be static, timeline or dynamic DM Tracks depending on applications. Each DM Track owns one or more DM Segments each of which strongly references the DM Framework
33、for Text-based Metadata. The Text-based DM Framework specifies the Generic Stream Text-based Sets and the UTF-8 or UTF-16 Text based Set as a Subclass of the Text-based Object to support the following two carriage mechanisms: 1. Generic Stream Partitions specified by SMPTE ST 410 are used for “bulky
34、“ text-based documents where the Generic Streams Payload is referenced through the Generic Stream Text-Based Set. The Generic Stream Text-based Set properties do not carry the text data, but include the linkage information (Stream SID) of the Generic Stream that contains the Text-based Metadata docu
35、ment. 2. Text-based Metadata is carried as payload of the- UTF-8 or UTF-16 Text-based Set. SMPTE RP 2057:2011 Page 5 of 14 pages Figure 1 illustrates the inheritance hierarchy of text-based Descriptive Metadata Sets by a UML diagram. Examples of the Header Metadata implementation and the linkage to
36、the Text-based Metadata are given in Section 8.3. Figure 1 Inheritance hierarchy of text-based Descriptive Metadata Sets 6 Generic Stream Partition for Text-based Metadata 6.1 Generic Stream Partition Pack The Generic Stream Partition Pack comprises a Generic Stream Partition Pack Key, a Length and
37、a Value as defined in SMPTE ST 410. 6.1.1 Generic Stream Partition Pack Key The Key of the Generic Stream Partition Pack shall be as defined in SMPTE ST 410. 6.1.2 Generic Stream Partition Pack Length The length field shall be as specified in SMPTE ST 410. 6.1.3 Generic Stream Partition Pack Values
38、The value of each item within the Generic Stream Partition Pack shall be as specified in SMPTE ST 410. Note: The Generic Stream Payload represents Metadata and not Essence. Consequently, according to SMPTE ST 410, there is not an entry in the Essence Containers Batches of the Partition Packs and the
39、 Preface Set to identify the Generic Streams Payload. Descriptive FrameworkDM SegmentGeneric Stream Text-based Set- Generic Stream SIDUTF-8 Text-based Set- UTF-8 Text dataText-based DM FrameworkText-based ObjectUTF-16 Text-based Set- UTF-16 Text dataLink to Generic Stream Payload containing textual
40、data1111Descriptive ObjectSMPTE RP 2057:2011 Page 6 of 14 pages 6.2 Generic Stream Data Element coding This sub-section provides the specification on Generic Stream Data Element coding for Text-Based Metadata carriage. 6.2.1 Generic Stream Data Element Key The default Generic Stream Data Element key
41、 defined in SMPTE ST 410 shall be used. Byte 12 of the Generic Stream Data Element Key signals the arrangement of the underlying data and the values shall be as given in Table 1. Table 1 Data Arrangement Byte 12 Bit Value Meaning 0 1 Marker bit to prevent termination of key 1 0 The KLV is not a part
42、 of the data and should be removed before processing 3,2 01 10 11 Generic Stream is Little-Endian Generic Stream is Big-Endian or is a byte-stream Endian-ness of the Generic Stream is unknown 7-4 0000 Reserved set to 0 Byte 13 of the Generic Stream Data Element Key signals the wrapping strategy appl
43、ied to the underlying data and the values shall be as given in Table 2. Applications that use UTF-16 encoding for the Text-based Metadata and the value of 11 for bits 3,2 shall define an alternative mechanism to signal the endian-ness of the Generic Stream Payload. Note: One mechanism to achieve thi
44、s is to require the Unicode byte order mark (BOM) to be present at the start of the text stream. Table 2 Wrapping Signaling Byte 13 Bit Value Meaning 0 1 Marker bit to prevent termination of key 1 0 The first byte of a KLV triplet has no special importance. 2 0 The Generic Stream is not divided into
45、 Access Units. 3 0 The Generic Stream Data is not Frame Wrapped. 7-4 0000 Reserved set to 0 6.2.2 Generic Stream Data Element Length The length field shall be as specified in SMPTE ST 410. 6.2.3 Generic Stream Data Element Value The value shall be the entire document of the Text-based Metadata. SMPT
46、E RP 2057:2011 Page 7 of 14 pages 6.3 Generic Stream Constraints The Generic Stream Partition shall contain a single KLV Packet which wraps the entire document of Text-based Metadata. If multiple documents need to be wrapped, then a separate Generic Stream shall be used for each document. The repeti
47、tions of the Generic Stream Payload shall be allowed. Indexing a Generic Stream Payload is not needed for Text-based Metadata and therefore the Index Table shall not be used. 7 Descriptive Metadata Scheme and Sets for Text-Based Metadata 7.1 Universal Label for Descriptive Metadata Scheme The presen
48、ce of Text-based DM Frameworks within the Header Metadata shall be signaled by adding the Universal Label defined in Table 3 to the Descriptive Metadata Scheme Batch of the Preface Set. Table 3 Descriptive Metadata Scheme UL value for Text-based Metadata Byte No. Description Value (hex) Meaning 112
49、See SMPTE ST 377-1 Universal Label for MXF Descriptive Metadata Schemes as defined by MXF File Format Specification 13 Structure / Scheme Kind 03h Text-based Descriptive Metadata Scheme 14 Scheme Version 01h Version 1 15 Framework Identification 01h Text-based DM Framework 16 Reserved 00h Reserved 7.2 Descriptive Metadata Set definitions 7.2.1 Descriptive Metadata Set Keys The common Key of the Descriptive Metadata Sets for the Text-based Metadata Scheme shall be as given in Table 4. Table 4 Common Key value for
