draft-ietf-cellar-ebml-10.txt   draft-ietf-cellar-ebml-11.txt 
cellar S. Lhomme cellar S. Lhomme
Internet-Draft Internet-Draft
Intended status: Standards Track D. Rice Intended status: Standards Track D. Rice
Expires: November 28, 2019 Expires: March 27, 2020
M. Bunkus M. Bunkus
May 27, 2019 September 24, 2019
Extensible Binary Meta Language Extensible Binary Meta Language
draft-ietf-cellar-ebml-10 draft-ietf-cellar-ebml-11
Abstract Abstract
This document defines the Extensible Binary Meta Language (EBML) This document defines the Extensible Binary Meta Language (EBML)
format as a generalized file format for any type of data in a format as a generalized file format for any type of data in a
hierarchical form. EBML is designed as a binary equivalent to XML hierarchical form. EBML is designed as a binary equivalent to XML
and uses a storage-efficient approach to build nested Elements with and uses a storage-efficient approach to build nested Elements with
identifiers, lengths, and values. Similar to how an XML Schema identifiers, lengths, and values. Similar to how an XML Schema
defines the structure and semantics of an XML Document, this document defines the structure and semantics of an XML Document, this document
defines how EBML Schemas are created to convey the semantics of an defines how EBML Schemas are created to convey the semantics of an
skipping to change at page 1, line 39 skipping to change at page 1, line 39
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This Internet-Draft will expire on November 28, 2019. This Internet-Draft will expire on March 27, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Notation and Conventions . . . . . . . . . . . . . . . . . . 4 2. Notation and Conventions . . . . . . . . . . . . . . . . . . 4
3. Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Variable Size Integer . . . . . . . . . . . . . . . . . . . . 7 4. Variable Size Integer . . . . . . . . . . . . . . . . . . . . 7
4.1. VINT_WIDTH . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. VINT_WIDTH . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. VINT_MARKER . . . . . . . . . . . . . . . . . . . . . . . 7 4.2. VINT_MARKER . . . . . . . . . . . . . . . . . . . . . . . 7
4.3. VINT_DATA . . . . . . . . . . . . . . . . . . . . . . . . 7 4.3. VINT_DATA . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4. VINT Examples . . . . . . . . . . . . . . . . . . . . . . 8 4.4. VINT Examples . . . . . . . . . . . . . . . . . . . . . . 8
5. Element ID . . . . . . . . . . . . . . . . . . . . . . . . . 9 5. Element ID . . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Element Data Size . . . . . . . . . . . . . . . . . . . . . . 10 6. Element Data Size . . . . . . . . . . . . . . . . . . . . . . 10
7. EBML Element Types . . . . . . . . . . . . . . . . . . . . . 12 6.1. Data Size Format . . . . . . . . . . . . . . . . . . . . 10
7.1. Signed Integer Element . . . . . . . . . . . . . . . . . 12 6.2. Unknown Data Size . . . . . . . . . . . . . . . . . . . . 11
7.2. Unsigned Integer Element . . . . . . . . . . . . . . . . 13 6.3. Data Size Values . . . . . . . . . . . . . . . . . . . . 12
7.3. Float Element . . . . . . . . . . . . . . . . . . . . . . 13 7. EBML Element Types . . . . . . . . . . . . . . . . . . . . . 13
7.4. String Element . . . . . . . . . . . . . . . . . . . . . 13 7.1. Signed Integer Element . . . . . . . . . . . . . . . . . 14
7.5. UTF-8 Element . . . . . . . . . . . . . . . . . . . . . . 13 7.2. Unsigned Integer Element . . . . . . . . . . . . . . . . 14
7.6. Date Element . . . . . . . . . . . . . . . . . . . . . . 13 7.3. Float Element . . . . . . . . . . . . . . . . . . . . . . 14
7.7. Master Element . . . . . . . . . . . . . . . . . . . . . 14 7.4. String Element . . . . . . . . . . . . . . . . . . . . . 15
7.8. Binary Element . . . . . . . . . . . . . . . . . . . . . 14 7.5. UTF-8 Element . . . . . . . . . . . . . . . . . . . . . . 15
8. EBML Document . . . . . . . . . . . . . . . . . . . . . . . . 14 7.6. Date Element . . . . . . . . . . . . . . . . . . . . . . 15
8.1. EBML Header . . . . . . . . . . . . . . . . . . . . . . . 15 7.7. Master Element . . . . . . . . . . . . . . . . . . . . . 15
8.2. EBML Body . . . . . . . . . . . . . . . . . . . . . . . . 15 7.8. Binary Element . . . . . . . . . . . . . . . . . . . . . 16
9. EBML Stream . . . . . . . . . . . . . . . . . . . . . . . . . 15 8. EBML Document . . . . . . . . . . . . . . . . . . . . . . . . 16
10. EBML Versioning . . . . . . . . . . . . . . . . . . . . . . . 15 8.1. EBML Header . . . . . . . . . . . . . . . . . . . . . . . 16
10.1. EBML Header Version . . . . . . . . . . . . . . . . . . 16 8.2. EBML Body . . . . . . . . . . . . . . . . . . . . . . . . 16
10.2. EBML Document Version . . . . . . . . . . . . . . . . . 16 9. EBML Stream . . . . . . . . . . . . . . . . . . . . . . . . . 17
11. Elements semantic . . . . . . . . . . . . . . . . . . . . . . 16 10. EBML Versioning . . . . . . . . . . . . . . . . . . . . . . . 17
11.1. EBML Schema . . . . . . . . . . . . . . . . . . . . . . 16 10.1. EBML Header Version . . . . . . . . . . . . . . . . . . 17
11.1.1. EBML Schema Example . . . . . . . . . . . . . . . . 17 10.2. EBML Document Version . . . . . . . . . . . . . . . . . 17
11.1.2. <EBMLSchema> Element . . . . . . . . . . . . . . . . 18 11. Elements semantic . . . . . . . . . . . . . . . . . . . . . . 17
11.1.3. <EBMLSchema> Attributes . . . . . . . . . . . . . . 18 11.1. EBML Schema . . . . . . . . . . . . . . . . . . . . . . 17
11.1.4. <element> Element . . . . . . . . . . . . . . . . . 18 11.1.1. EBML Schema Example . . . . . . . . . . . . . . . . 18
11.1.5. <element> Attributes . . . . . . . . . . . . . . . . 19 11.1.2. <EBMLSchema> Element . . . . . . . . . . . . . . . . 19
11.1.6. <documentation> Element . . . . . . . . . . . . . . 24 11.1.3. <EBMLSchema> Attributes . . . . . . . . . . . . . . 19
11.1.7. <documentation> Attributes . . . . . . . . . . . . . 24 11.1.4. <element> Element . . . . . . . . . . . . . . . . . 20
11.1.8. <restriction> Element . . . . . . . . . . . . . . . 25 11.1.5. <element> Attributes . . . . . . . . . . . . . . . . 20
11.1.9. <enum> Element . . . . . . . . . . . . . . . . . . . 25 11.1.6. <documentation> Element . . . . . . . . . . . . . . 26
11.1.10. <enum> Attributes . . . . . . . . . . . . . . . . . 25 11.1.7. <documentation> Attributes . . . . . . . . . . . . . 26
11.1.11. XML Schema for EBML Schema . . . . . . . . . . . . . 26 11.1.8. <implementation_note> Element . . . . . . . . . . . 26
11.1.12. Identically Recurring Elements . . . . . . . . . . . 27 11.1.9. <implementation_note> Attributes . . . . . . . . . . 27
11.1.13. Textual expression of floats . . . . . . . . . . . . 28 11.1.10. <restriction> Element . . . . . . . . . . . . . . . 27
11.1.14. Note on the use of default attributes to define 11.1.11. <enum> Element . . . . . . . . . . . . . . . . . . . 27
Mandatory EBML Elements . . . . . . . . . . . . . . 28 11.1.12. <enum> Attributes . . . . . . . . . . . . . . . . . 27
11.2. EBML Header Elements . . . . . . . . . . . . . . . . . . 29 11.1.13. <extension> Element . . . . . . . . . . . . . . . . 28
11.2.1. EBML Element . . . . . . . . . . . . . . . . . . . . 29 11.1.14. <extension> Attributes . . . . . . . . . . . . . . . 28
11.2.2. EBMLVersion Element . . . . . . . . . . . . . . . . 29 11.1.15. XML Schema for EBML Schema . . . . . . . . . . . . . 28
11.2.3. EBMLReadVersion Element . . . . . . . . . . . . . . 30 11.1.16. Identically Recurring Elements . . . . . . . . . . . 31
11.2.4. EBMLMaxIDLength Element . . . . . . . . . . . . . . 30 11.1.17. Textual expression of floats . . . . . . . . . . . . 31
11.2.5. EBMLMaxSizeLength Element . . . . . . . . . . . . . 31 11.1.18. Note on the use of default attributes to define
11.2.6. DocType Element . . . . . . . . . . . . . . . . . . 31 Mandatory EBML Elements . . . . . . . . . . . . . . 32
11.2.7. DocTypeVersion Element . . . . . . . . . . . . . . . 32 11.2. EBML Header Elements . . . . . . . . . . . . . . . . . . 33
11.2.8. DocTypeReadVersion Element . . . . . . . . . . . . . 32 11.2.1. EBML Element . . . . . . . . . . . . . . . . . . . . 33
11.2.9. DocTypeExtension Element . . . . . . . . . . . . . . 33 11.2.2. EBMLVersion Element . . . . . . . . . . . . . . . . 33
11.2.10. DocTypeExtensionName Element . . . . . . . . . . . . 33 11.2.3. EBMLReadVersion Element . . . . . . . . . . . . . . 34
11.2.11. DocTypeExtensionVersion Element . . . . . . . . . . 34 11.2.4. EBMLMaxIDLength Element . . . . . . . . . . . . . . 34
11.3. Global Elements . . . . . . . . . . . . . . . . . . . . 34 11.2.5. EBMLMaxSizeLength Element . . . . . . . . . . . . . 35
11.3.1. CRC-32 Element . . . . . . . . . . . . . . . . . . . 34 11.2.6. DocType Element . . . . . . . . . . . . . . . . . . 35
11.3.2. Void Element . . . . . . . . . . . . . . . . . . . . 35 11.2.7. DocTypeVersion Element . . . . . . . . . . . . . . . 36
12. Considerations for Reading EBML Data . . . . . . . . . . . . 35 11.2.8. DocTypeReadVersion Element . . . . . . . . . . . . . 36
13. Terminating Elements . . . . . . . . . . . . . . . . . . . . 36 11.2.9. DocTypeExtension Element . . . . . . . . . . . . . . 37
14. Guidelines for Updating Elements . . . . . . . . . . . . . . 36 11.2.10. DocTypeExtensionName Element . . . . . . . . . . . . 37
14.1. Reducing a Element Data in Size . . . . . . . . . . . . 36 11.2.11. DocTypeExtensionVersion Element . . . . . . . . . . 37
14.1.1. Adding a Void Element . . . . . . . . . . . . . . . 36 11.3. Global Elements . . . . . . . . . . . . . . . . . . . . 38
14.1.2. Extending the Element Data Size . . . . . . . . . . 37 11.3.1. CRC-32 Element . . . . . . . . . . . . . . . . . . . 38
14.1.3. Terminating Element Data . . . . . . . . . . . . . . 38 11.3.2. Void Element . . . . . . . . . . . . . . . . . . . . 39
12. Considerations for Reading EBML Data . . . . . . . . . . . . 39
13. Terminating Elements . . . . . . . . . . . . . . . . . . . . 39
14. Guidelines for Updating Elements . . . . . . . . . . . . . . 40
14.1. Reducing a Element Data in Size . . . . . . . . . . . . 40
14.1.1. Adding a Void Element . . . . . . . . . . . . . . . 40
14.1.2. Extending the Element Data Size . . . . . . . . . . 40
14.1.3. Terminating Element Data . . . . . . . . . . . . . . 41
14.2. Considerations when Updating Elements with Cyclic 14.2. Considerations when Updating Elements with Cyclic
Redundancy Check (CRC) . . . . . . . . . . . . . . . . . 38 Redundancy Check (CRC) . . . . . . . . . . . . . . . . . 42
15. Backward and Forward Compatibility . . . . . . . . . . . . . 38 15. Backward and Forward Compatibility . . . . . . . . . . . . . 42
15.1. Backward Compatibility . . . . . . . . . . . . . . . . . 38 15.1. Backward Compatibility . . . . . . . . . . . . . . . . . 42
15.2. Forward Compatibility . . . . . . . . . . . . . . . . . 39 15.2. Forward Compatibility . . . . . . . . . . . . . . . . . 42
16. Security Considerations . . . . . . . . . . . . . . . . . . . 39 16. Security Considerations . . . . . . . . . . . . . . . . . . . 43
17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 41 17. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44
17.1. CELLAR EBML Element ID Registry . . . . . . . . . . . . 41 17.1. CELLAR EBML Element ID Registry . . . . . . . . . . . . 44
17.2. CELLAR EBML DocType Registry . . . . . . . . . . . . . . 43 17.2. CELLAR EBML DocType Registry . . . . . . . . . . . . . . 46
18. References . . . . . . . . . . . . . . . . . . . . . . . . . 43 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 47
18.1. Normative References . . . . . . . . . . . . . . . . . . 43 18.1. Normative References . . . . . . . . . . . . . . . . . . 47
18.2. Informative References . . . . . . . . . . . . . . . . . 44 18.2. Informative References . . . . . . . . . . . . . . . . . 48
18.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 45 18.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 48
1. Introduction 1. Introduction
EBML, short for Extensible Binary Meta Language, specifies a binary EBML, short for Extensible Binary Meta Language, specifies a binary
and octet (byte) aligned format inspired by the principle of XML (a and octet (byte) aligned format inspired by the principle of XML (a
framework for structuring data). framework for structuring data).
The goal of this document is to define a generic, binary, space- The goal of this document is to define a generic, binary, space-
efficient format that can be used to define more complex formats efficient format that can be used to define more complex formats
using an EBML Schema. EBML is used by the multimedia container using an EBML Schema. EBML is used by the multimedia container
skipping to change at page 10, line 16 skipping to change at page 10, line 41
| EBML Class | Length | Possible IDs | Number of IDs | | EBML Class | Length | Possible IDs | Number of IDs |
+------------+--------+-------------------------+---------------+ +------------+--------+-------------------------+---------------+
| Class A | 1 | 0x81 - 0xFE | 126 | | Class A | 1 | 0x81 - 0xFE | 126 |
| Class B | 2 | 0x407F - 0x7FFE | 16,256 | | Class B | 2 | 0x407F - 0x7FFE | 16,256 |
| Class C | 3 | 0x203FFF - 0x3FFFFE | 2,080,768 | | Class C | 3 | 0x203FFF - 0x3FFFFE | 2,080,768 |
| Class D | 4 | 0x101FFFFF - 0x1FFFFFFE | 268,338,304 | | Class D | 4 | 0x101FFFFF - 0x1FFFFFFE | 268,338,304 |
+------------+--------+-------------------------+---------------+ +------------+--------+-------------------------+---------------+
6. Element Data Size 6. Element Data Size
6.1. Data Size Format
The Element Data Size expresses the length in octets of Element Data. The Element Data Size expresses the length in octets of Element Data.
The Element Data Size itself is encoded as a Variable Size Integer. The Element Data Size itself is encoded as a Variable Size Integer.
By default, Element Data Sizes can be encoded in lengths from one By default, Element Data Sizes can be encoded in lengths from one
octet to eight octets, although Element Data Sizes of greater lengths octet to eight octets, although Element Data Sizes of greater lengths
MAY be used if the octet length of the longest Element Data Size of MAY be used if the octet length of the longest Element Data Size of
the EBML Document is declared in the EBMLMaxSizeLength Element of the the EBML Document is declared in the EBMLMaxSizeLength Element of the
EBML Header (see Section 11.2.5). Unlike the VINT_DATA of the EBML Header (see Section 11.2.5). Unlike the VINT_DATA of the
Element ID, the VINT_DATA component of the Element Data Size is not Element ID, the VINT_DATA component of the Element Data Size is not
mandated to be encoded at the shortest valid length. For example, an mandated to be encoded at the shortest valid length. For example, an
Element Data Size with binary encoding of 1011 1111 or a binary Element Data Size with binary encoding of 1011 1111 or a binary
skipping to change at page 10, line 44 skipping to change at page 11, line 22
(see Section 7). An Element Data Size with all VINT_DATA bits set to (see Section 7). An Element Data Size with all VINT_DATA bits set to
zero indicates that the Element Data is zero octets in length. Such zero indicates that the Element Data is zero octets in length. Such
an EBML Element is referred to as an Empty Element. If an Empty an EBML Element is referred to as an Empty Element. If an Empty
Element has a default value declared then the EBML Reader MUST Element has a default value declared then the EBML Reader MUST
interpret the value of the Empty Element as the default value. If an interpret the value of the Empty Element as the default value. If an
Empty Element has no default value declared then the EBML Reader MUST Empty Element has no default value declared then the EBML Reader MUST
use the value of the Empty Element for the corresponding EBML Element use the value of the Empty Element for the corresponding EBML Element
Type of the Element ID, 0 for numbers and an empty string for Type of the Element ID, 0 for numbers and an empty string for
strings. strings.
6.2. Unknown Data Size
An Element Data Size with all VINT_DATA bits set to one is reserved An Element Data Size with all VINT_DATA bits set to one is reserved
as an indicator that the size of the EBML Element is unknown. The as an indicator that the size of the EBML Element is unknown. The
only reserved value for the VINT_DATA of Element Data Size is all only reserved value for the VINT_DATA of Element Data Size is all
bits set to one. An EBML Element with an unknown Element Data Size bits set to one. An EBML Element with an unknown Element Data Size
is referred to as an Unknown-Sized Element. A Master Element MAY be is referred to as an Unknown-Sized Element. A Master Element MAY be
an Unknown-Sized Element; however an EBML Element that is not a an Unknown-Sized Element; however an EBML Element that is not a
Master Element MUST NOT be an Unknown-Sized Element. Master Elements Master Element MUST NOT be an Unknown-Sized Element. Master Elements
MUST NOT use an unknown size unless the unknownsizeallowed attribute MUST NOT use an unknown size unless the unknownsizeallowed attribute
of their EBML Schema is set to true (see Section 11.1.5.10). The use of their EBML Schema is set to true (see Section 11.1.5.10).
of Unknown-Sized Elements allows for an EBML Element to be written
and read before the size of the EBML Element is known. Unknown-Sized The use of Unknown-Sized Elements allows for an EBML Element to be
Element MUST NOT be used or defined unnecessarily; however if the written and read before the size of the EBML Element is known.
Element Data Size is not known before the Element Data is written, Unknown-Sized Element MUST NOT be used or defined unnecessarily;
such as in some cases of data streaming, then Unknown-Sized Elements however if the Element Data Size is not known before the Element Data
MAY be used. The end of an Unknown-Sized Element is determined by is written, such as in some cases of data streaming, then Unknown-
whichever comes first: the end of the file or the beginning of the Sized Elements MAY be used. The end of an Unknown-Sized Element is
next EBML Element, defined by this document or the corresponding EBML determined by whichever comes first:
Schema, that is not independently valid as Descendant Element of the
Unknown-Sized Element. o Any EBML Element that is a valid Parent Element of the Unknown-
Sized Element according to the EBML Schema, Section 11.3 excluded.
o Any valid EBML Element according to the EBML Schema, Section 11.3
excluded, that is not a Descendant Element of the Unknown-Sized
Element but share a common direct parent, such as a Top-Level
Element.
o Any EBML Element that is a valid Root Element according to the
EBML Schema, Section 11.3 excluded.
o The end of the Parent Element with a known size has been reached.
o The end of the EBML Document, either when reaching the end of the
file or because a new EBML Header started.
Consider an Unknown-Sized Element which EBML path is
"\root\level1\level2\elt". When reading a new Element ID, assuming
the EBML Path of that new Element is valid, here are some possible
and impossible ways that this new Element is ending "elt":
+------------------------------------+------------------------------+
| EBML Path of new element | Status |
+------------------------------------+------------------------------+
| "\root\level1\level2" | Ends the Unknown-Sized |
| | Element, as it is a new |
| | Parent Element |
| "\root\level1" | Ends the Unknown-Sized |
| | Element, as it is a new |
| | Parent Element |
| "\root" | Ends the Unknown-Sized |
| | Element, as it is a new Root |
| | Element |
| "\root2" | Ends the Unknown-Sized |
| | Element, as it is a new Root |
| | Element |
| "\root\level1\level2\other" | Ends the Unknown-Sized |
| | Element, as they share the |
| | same parent |
| "\root\level1\level2\elt" | Ends the Unknown-Sized |
| | Element, as they share the |
| | same parent |
| "\root\level1\level2\elt\inside" | Doesn't end the Unknown- |
| | Sized Element, it's a child |
| | of "elt" |
| "\root\level1\level2\elt\<global>" | Global Element is valid, |
| | it's a child of "elt" |
| "\root\level1\level2\<global>" | Global Element cannot be |
| | assumed to have this path, |
| | while parsing "elt" it can |
| | only be a child of "elt" |
+------------------------------------+------------------------------+
6.3. Data Size Values
For Element Data Sizes encoded at octet lengths from one to eight, For Element Data Sizes encoded at octet lengths from one to eight,
this table depicts the range of possible values that can be encoded this table depicts the range of possible values that can be encoded
as an Element Data Size. An Element Data Size with an octet length as an Element Data Size. An Element Data Size with an octet length
of 8 is able to express a size of 2^56-2 or 72,057,594,037,927,934 of 8 is able to express a size of 2^56-2 or 72,057,594,037,927,934
octets (or about 72 petabytes). The maximum possible value that can octets (or about 72 petabytes). The maximum possible value that can
be stored as Element Data Size is referred to as VINTMAX. be stored as Element Data Size is referred to as VINTMAX.
+--------------+----------------------+ +--------------+----------------------+
| Octet Length | Possible Value Range | | Octet Length | Possible Value Range |
skipping to change at page 11, line 37 skipping to change at page 13, line 22
| 3 | 0 to 2^21-2 | | 3 | 0 to 2^21-2 |
| 4 | 0 to 2^28-2 | | 4 | 0 to 2^28-2 |
| 5 | 0 to 2^35-2 | | 5 | 0 to 2^35-2 |
| 6 | 0 to 2^42-2 | | 6 | 0 to 2^42-2 |
| 7 | 0 to 2^49-2 | | 7 | 0 to 2^49-2 |
| 8 | 0 to 2^56-2 | | 8 | 0 to 2^56-2 |
+--------------+----------------------+ +--------------+----------------------+
If the length of Element Data equals 2^(n*7)-1 then the octet length If the length of Element Data equals 2^(n*7)-1 then the octet length
of the Element Data Size MUST be at least n+1. This rule prevents an of the Element Data Size MUST be at least n+1. This rule prevents an
Element Data Size from being expressed as a reserved value. The Element Data Size from being expressed as the unknown size value.
following table clarifies this rule by showing a valid and invalid The following table clarifies this rule by showing a valid and
expression of an Element Data Size with a VINT_DATA of 127 (which is invalid expression of an Element Data Size with a VINT_DATA of 127
equal to 2^(1*7)-1) and 16,383 (which is equal to 2^(2*7)-1). (which is equal to 2^(1*7)-1) and 16,383 (which is equal to 2^(2*7)-
1).
+------------+-------------+-----------------------+----------------+ +------------+-------------+-----------------------+----------------+
| VINT_WIDTH | VINT_MARKER | VINT_DATA | Element Data | | VINT_WIDTH | VINT_MARKER | VINT_DATA | Element Data |
| | | | Size Status | | | | | Size Status |
+------------+-------------+-----------------------+----------------+ +------------+-------------+-----------------------+----------------+
| | 1 | 1111111 | Reserved | | | 1 | 1111111 | Reserved |
| | | | (meaning | | | | | (meaning |
| | | | Unknown) | | | | | Unknown) |
| 0 | 1 | 00000001111111 | Valid (meaning | | 0 | 1 | 00000001111111 | Valid (meaning |
| | | | 127 octets) | | | | | 127 octets) |
skipping to change at page 12, line 25 skipping to change at page 13, line 48
| | | | 127 octets) | | | | | 127 octets) |
| 0 | 1 | 11111111111111 | Reserved | | 0 | 1 | 11111111111111 | Reserved |
| | | | (meaning | | | | | (meaning |
| | | | Unknown) | | | | | Unknown) |
| 00 | 1 | 000000011111111111111 | Valid (16,383 | | 00 | 1 | 000000011111111111111 | Valid (16,383 |
| | | | octets) | | | | | octets) |
+------------+-------------+-----------------------+----------------+ +------------+-------------+-----------------------+----------------+
7. EBML Element Types 7. EBML Element Types
EBML Elements are defined by an EBML Schema which MUST declare one of EBML Elements are defined by an EBML Schema (see Section 11.1) which
the following EBML Element Types for each EBML Element. An EBML MUST declare one of the following EBML Element Types for each EBML
Element Type defines a concept of storing data within an EBML Element Element. An EBML Element Type defines a concept of storing data
that describes such characteristics as length, endianness, and within an EBML Element that describes such characteristics as length,
definition. endianness, and definition.
EBML Elements which are defined as a Signed Integer Element, Unsigned EBML Elements which are defined as a Signed Integer Element, Unsigned
Integer Element, Float Element, or Date Element use big endian Integer Element, Float Element, or Date Element use big endian
storage. storage.
7.1. Signed Integer Element 7.1. Signed Integer Element
A Signed Integer Element MUST declare a length from zero to eight A Signed Integer Element MUST declare a length from zero to eight
octets. If the EBML Element is not defined to have a default value, octets. If the EBML Element is not defined to have a default value,
then a Signed Integer Element with a zero-octet length represents an then a Signed Integer Element with a zero-octet length represents an
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The version of the EBML Body is found in EBMLDocTypeVersion. A The version of the EBML Body is found in EBMLDocTypeVersion. A
parser for the particular DocType format can read the EBML Document parser for the particular DocType format can read the EBML Document
if it can read either the EBMLDocTypeVersion version of that format if it can read either the EBMLDocTypeVersion version of that format
or a version equal or higher than the one found in or a version equal or higher than the one found in
EBMLDocTypeReadVersion. EBMLDocTypeReadVersion.
11. Elements semantic 11. Elements semantic
11.1. EBML Schema 11.1. EBML Schema
An EBML Schema is a well-formed XML Document that defines the An EBML Schema is a well-formed XML Document [W3C.REC-xml-20081126]
properties, arrangement, and usage of EBML Elements that compose a that defines the properties, arrangement, and usage of EBML Elements
specific EBML Document Type. The relationship of an EBML Schema to that compose a specific EBML Document Type. The relationship of an
an EBML Document is analogous to the relationship of an XML Schema EBML Schema to an EBML Document is analogous to the relationship of
[W3C.REC-xmlschema-0-20010502] to an XML Document an XML Schema [W3C.REC-xmlschema-0-20041028] to an XML Document
[W3C.REC-xml-20081126]. An EBML Schema MUST be clearly associated [W3C.REC-xml-20081126]. An EBML Schema MUST be clearly associated
with one or more EBML Document Types. An EBML Document Type is with one or more EBML Document Types. An EBML Document Type is
identified by a string stored within the EBML Header in the DocType identified by a string stored within the EBML Header in the DocType
Element; for example matroska or webm (see Section 11.2.6). The Element; for example matroska or webm (see Section 11.2.6). The
DocType value for an EBML Document Type MUST be unique and DocType value for an EBML Document Type MUST be unique and
persistent. persistent.
An EBML Schema MUST declare exactly one EBML Element at Root Level An EBML Schema MUST declare exactly one EBML Element at Root Level
(referred to as the Root Element) that occurs exactly once within an (referred to as the Root Element) that occurs exactly once within an
EBML Document. The Void Element MAY also occur at Root Level but is EBML Document. The Void Element MAY also occur at Root Level but is
skipping to change at page 17, line 24 skipping to change at page 18, line 42
docType="files-in-ebml-demo" version="1"> docType="files-in-ebml-demo" version="1">
<!-- constraints to the range of two EBML Header Elements --> <!-- constraints to the range of two EBML Header Elements -->
<element name="EBMLReadVersion" path="1*1(\EBML\EBMLReadVersion)" <element name="EBMLReadVersion" path="1*1(\EBML\EBMLReadVersion)"
id="0x42F7" minOccurs="1" maxOccurs="1" range="1" default="1" id="0x42F7" minOccurs="1" maxOccurs="1" range="1" default="1"
type="uinteger"/> type="uinteger"/>
<element name="EBMLMaxSizeLength" path="1*1(\EBML\EBMLMaxSizeLength)" <element name="EBMLMaxSizeLength" path="1*1(\EBML\EBMLMaxSizeLength)"
id="0x42F3" minOccurs="1" maxOccurs="1" range="8" default="8" id="0x42F3" minOccurs="1" maxOccurs="1" range="8" default="8"
type="uinteger"/> type="uinteger"/>
<!-- Root Element--> <!-- Root Element-->
<element name="Files" path="*1(\Files)" id="0x1946696C" type="master"> <element name="Files" path="*1(\Files)" id="0x1946696C" type="master">
<documentation lang="en" type="definition">Container of data and <documentation lang="en" purpose="definition">Container of data and
attributes representing one or many files.</documentation> attributes representing one or many files.</documentation>
</element> </element>
<element name="File" path="1*(\Files\File)" id="0x6146" type="master" <element name="File" path="1*(\Files\File)" id="0x6146" type="master"
minOccurs="1"> minOccurs="1">
<documentation lang="en" type="definition"> <documentation lang="en" purpose="definition">
An attached file. An attached file.
</documentation> </documentation>
</element> </element>
<element name="FileName" path="1*1(\Files\File\FileName)" <element name="FileName" path="1*1(\Files\File\FileName)"
id="0x614E" type="utf-8" id="0x614E" type="utf-8"
minOccurs="1"> minOccurs="1">
<documentation lang="en" type="definition"> <documentation lang="en" purpose="definition">
Filename of the attached file. Filename of the attached file.
</documentation> </documentation>
</element> </element>
<element name="MimeType" path="1*1(\Files\File\MimeType)" <element name="MimeType" path="1*1(\Files\File\MimeType)"
id="0x464D" type="string" id="0x464D" type="string"
minOccurs="1"> minOccurs="1">
<documentation lang="en" type="definition"> <documentation lang="en" purpose="definition">
MIME type of the file. MIME type of the file.
</documentation> </documentation>
</element> </element>
<element name="ModificationTimestamp" <element name="ModificationTimestamp"
path="1*1(\Files\File\ModificationTimestamp)" id="0x4654" path="1*1(\Files\File\ModificationTimestamp)" id="0x4654"
type="date" minOccurs="1"> type="date" minOccurs="1">
<documentation lang="en" type="definition"> <documentation lang="en" purpose="definition">
Modification timestamp of the file. Modification timestamp of the file.
</documentation> </documentation>
</element> </element>
<element name="Data" path="1*1(\Files\File\Data)" id="0x4664" <element name="Data" path="1*1(\Files\File\Data)" id="0x4664"
type="binary" minOccurs="1"> type="binary" minOccurs="1">
<documentation lang="en" type="definition"> <documentation lang="en" purpose="definition">
The data of the file. The data of the file.
</documentation> </documentation>
</element> </element>
</EBMLSchema> </EBMLSchema>
11.1.2. <EBMLSchema> Element 11.1.2. <EBMLSchema> Element
As an XML Document, the EBML Schema MUST use "<EBMLSchema>" as the As an XML Document, the EBML Schema MUST use "<EBMLSchema>" as the
top level element. The "<EBMLSchema>" element MAY contain top level element. The "<EBMLSchema>" element can contain
"<element>" sub-elements. "<element>" sub-elements.
11.1.3. <EBMLSchema> Attributes 11.1.3. <EBMLSchema> Attributes
Within an EBML Schema the "<EBMLSchema>" element uses the following Within an EBML Schema the "<EBMLSchema>" element uses the following
attributes: attributes:
11.1.3.1. docType 11.1.3.1. docType
The docType lists the official name of the EBML Document Type that is The docType lists the official name of the EBML Document Type that is
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11.1.4. <element> Element 11.1.4. <element> Element
Each "<element>" defines one EBML Element through the use of several Each "<element>" defines one EBML Element through the use of several
attributes that are defined in Section 11.1.3. EBML Schemas MAY attributes that are defined in Section 11.1.3. EBML Schemas MAY
contain additional attributes to extend the semantics but MUST NOT contain additional attributes to extend the semantics but MUST NOT
conflict with the definitions of the "<element>" attributes defined conflict with the definitions of the "<element>" attributes defined
within this document. within this document.
The "<element>" nodes contain a description of the meaning and use of The "<element>" nodes contain a description of the meaning and use of
the EBML Element stored within one or more "<documentation>" sub- the EBML Element stored within one or more "<documentation>" sub-
elements and zero or one "<restriction>" sub-element. All elements, followed by optional "<implementation_note>" sub-elements,
"<element>" nodes MUST be sub-elements of the "<EBMLSchema>". followed by zero or one "<restriction>" sub-element, followed by
optional "<extension>" sub-elements. All "<element>" nodes MUST be
sub-elements of the "<EBMLSchema>".
11.1.5. <element> Attributes 11.1.5. <element> Attributes
Within an EBML Schema the "<element>" uses the following attributes Within an EBML Schema the "<element>" uses the following attributes
to define an EBML Element: to define an EBML Element:
11.1.5.1. name 11.1.5.1. name
The name provides the human-readable name of the EBML Element. The The name provides the human-readable name of the EBML Element. The
value of the name MUST be in the form of characters "A" to "Z", "a" value of the name MUST be in the form of characters "A" to "Z", "a"
to "z", "0" to "9", "-" and ".". to "z", "0" to "9", "-" and ".".
The name attribute is REQUIRED. The name attribute is REQUIRED.
11.1.5.2. path 11.1.5.2. path
The path defines the allowed storage locations of the EBML Element The path defines the allowed storage locations of the EBML Element
within an EBML Document. This path MUST be defined with the full within an EBML Document. This path MUST be defined with the full
hierarchy of EBML Elements separated with a "/". The top EBML hierarchy of EBML Elements separated with a "\". The top EBML
Element in the path hierarchy being the first in the value. The Element in the path hierarchy being the first in the value. The
syntax of the path attribute is defined using this Augmented Backus- syntax of the path attribute is defined using this Augmented Backus-
Naur Form (ABNF) [RFC5234] with the case sensitive update [RFC7405] Naur Form (ABNF) [RFC5234] with the case sensitive update [RFC7405]
notation: notation:
The path attribute is REQUIRED. The path attribute is REQUIRED.
EBMLFullPath = EBMLElementOccurrence "(" EBMLMasterPath ")" EBMLFullPath = EBMLElementOccurrence "(" EBMLMasterPath ")"
EBMLMasterPath = [EBMLParentPath] EBMLElementPath EBMLMasterPath = [EBMLParentPath] EBMLElementPath
EBMLParentPath = EBMLFixedParent EBMLLastParent EBMLParentPath = EBMLFixedParent EBMLLastParent
EBMLFixedParent = *(EBMLPathAtom) EBMLFixedParent = *(EBMLPathAtom)
EBMLElementPath = EBMLPathAtom / EBMLPathAtomRecursive EBMLElementPath = EBMLPathAtom / EBMLPathAtomRecursive
EBMLPathAtom = PathDelimiter EBMLAtomName EBMLPathAtom = PathDelimiter EBMLAtomName
EBMLPathAtomRecursive = "(1*(" EBMLPathAtom "))" EBMLPathAtomRecursive = "(1*(" EBMLPathAtom "))"
EBMLLastParent = EBMLPathAtom / EBMLVariableParent EBMLLastParent = EBMLPathAtom / EBMLVariableParent
EBMLVariableParent = "(" VariableParentOccurrence "\)" EBMLVariableParent = "(" VariableParentOccurrence "\)"
EBMLAtomName = 1*(EBMLNameChar) EBMLAtomName = 1*(EBMLNameChar)
EBMLNameChar = ALPHA / DIGIT / "-" / "." EBMLNameChar = ALPHA / DIGIT / "-" / "."
PathDelimiter = "\" PathDelimiter = "\"
EBMLElementOccurrence = [EBMLMinOccurrence] "*" [EBMLMaxOccurrence] EBMLElementOccurrence = [EBMLMinOccurrence] "*" [EBMLMaxOccurrence]
EBMLMinOccurrence = 1*DIGIT EBMLMinOccurrence = 1*DIGIT ; no upper limit
EBMLMaxOccurrence = 1*DIGIT EBMLMaxOccurrence = 1*DIGIT ; no upper limit
VariableParentOccurrence = [PathMinOccurrence] "*" [PathMaxOccurrence] VariableParentOccurrence = [PathMinOccurrence] "*" [PathMaxOccurrence]
PathMinOccurrence = 1*DIGIT PathMinOccurrence = 1*DIGIT ; no upper limit
PathMaxOccurrence = 1*DIGIT PathMaxOccurrence = 1*DIGIT ; no upper limit
The "*", "(" and ")" symbols are interpreted as defined in [RFC5234]. The "*", "(" and ")" symbols are interpreted as defined in [RFC5234].
The EBMLPathAtom part of the EBMLElementPath MUST be equal to the The EBMLPathAtom part of the EBMLElementPath MUST be equal to the
name attribute of the EBML Schema. name attribute of the EBML Schema.
The starting PathDelimiter of the path corresponds to the root of the The starting PathDelimiter of the path corresponds to the root of the
EBML Document. EBML Document.
The EBMLElementOccurrence part is interpreted as an ABNF Variable The EBMLElementOccurrence part is interpreted as an ABNF Variable
Repetition. The repetition amounts correspond to how many times the Repetition. The repetition amounts correspond to how many times the
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instance of the Parent Element MUST contain at least this many instance of the Parent Element MUST contain at least this many
instances of this EBML Element. If the EBML Element has an empty instances of this EBML Element. If the EBML Element has an empty
EBMLParentPath then EBMLMinOccurrence refers to constraints on the EBMLParentPath then EBMLMinOccurrence refers to constraints on the
occurrence of the EBML Element within the EBML Document. If occurrence of the EBML Element within the EBML Document. If
EBMLMinOccurrence is not present then that EBML Element has an EBMLMinOccurrence is not present then that EBML Element has an
EBMLMinOccurrence value of 0. The semantic meaning of EBMLMinOccurrence value of 0. The semantic meaning of
EBMLMinOccurrence within an EBML Schema is analogous to the meaning EBMLMinOccurrence within an EBML Schema is analogous to the meaning
of minOccurs within an XML Schema. EBML Elements with of minOccurs within an XML Schema. EBML Elements with
EBMLMinOccurrence set to "1" that also have a default value (see EBMLMinOccurrence set to "1" that also have a default value (see
Section 11.1.5.8) declared are not REQUIRED to be stored but are Section 11.1.5.8) declared are not REQUIRED to be stored but are
REQUIRED to be interpreted, see Section 11.1.14. An EBML Element REQUIRED to be interpreted, see Section 11.1.18. An EBML Element
defined with a EBMLMinOccurrence value greater than zero is called a defined with a EBMLMinOccurrence value greater than zero is called a
Mandatory EBML Element. Mandatory EBML Element.
The EBMLMaxOccurrence represents the maximum permitted number of The EBMLMaxOccurrence represents the maximum permitted number of
occurrences of this EBML Element within its Parent Element. Each occurrences of this EBML Element within its Parent Element. Each
instance of the Parent Element MUST contain at most this many instance of the Parent Element MUST contain at most this many
instances of this EBML Element. If the EBML Element has an empty instances of this EBML Element. If the EBML Element has an empty
EBMLParentPath then EBMLMaxOccurrence refers to constraints on the EBMLParentPath then EBMLMaxOccurrence refers to constraints on the
occurrence of the EBML Element within the EBML Document. If occurrence of the EBML Element within the EBML Document. If
EBMLMaxOccurrence is not present then there is no upper bound for the EBMLMaxOccurrence is not present then there is no upper bound for the
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attribute value. For example "1234" means the EBML element always attribute value. For example "1234" means the EBML element always
has the value 1234. The value can be prefixed with "not" to indicate has the value 1234. The value can be prefixed with "not" to indicate
that the fixed value MUST NOT be used for that Element. For example that the fixed value MUST NOT be used for that Element. For example
"not 1234" means the Element can use all values of its type except "not 1234" means the Element can use all values of its type except
1234. 1234.
For an exclusive lower boundary the ">" sign is used and the ">=" For an exclusive lower boundary the ">" sign is used and the ">="
sign is used for an inclusive lower boundary. For example ">3" sign is used for an inclusive lower boundary. For example ">3"
meaning the Element value MUST be greater than 3 or ">=0x1p+0" meaning the Element value MUST be greater than 3 or ">=0x1p+0"
meaning the Element value MUST be greater than or equal to the meaning the Element value MUST be greater than or equal to the
floating value 1.0, see Section 11.1.13. floating value 1.0, see Section 11.1.17.
For an exclusive upper boundary the "<" sign is used and the "<=" For an exclusive upper boundary the "<" sign is used and the "<="
sign is used for an inclusive upper boundary. For example "<-2" sign is used for an inclusive upper boundary. For example "<-2"
meaning the Element value MUST be less than -2 or "<=10" meaning the meaning the Element value MUST be less than -2 or "<=10" meaning the
Element value MUST be less than or equal to the 10. Element value MUST be less than or equal to the 10.
The lower and upper bounds can be combined into an expression to form The lower and upper bounds can be combined into an expression to form
a closed boundary. The lower boundary coming first followed by the a closed boundary. The lower boundary coming first followed by the
upper boundary, separated by a comma. For example ">3,<= 20" means upper boundary, separated by a comma. For example ">3,<= 20" means
the Element value MUST be greater than 3 and less than or equal to the Element value MUST be greater than 3 and less than or equal to
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11.1.5.10. unknownsizeallowed 11.1.5.10. unknownsizeallowed
A boolean to express if an EBML Element is permitted to be Unknown- A boolean to express if an EBML Element is permitted to be Unknown-
Sized Element (having all VINT_DATA bits of Element Data Size set to Sized Element (having all VINT_DATA bits of Element Data Size set to
1). EBML Elements that are not Master Elements MUST NOT set 1). EBML Elements that are not Master Elements MUST NOT set
unknownsizeallowed to true. An EBML Element that is defined with an unknownsizeallowed to true. An EBML Element that is defined with an
unknownsizeallowed attribute set to 1 MUST also have the unknownsizeallowed attribute set to 1 MUST also have the
unknownsizeallowed attribute of its Parent Element set to 1. unknownsizeallowed attribute of its Parent Element set to 1.
An EBML Element with the unknownsizeallowed attribute set to 1 MUST
NOT have its recursive attribute set to 1.
The unknownsizeallowed attribute is OPTIONAL. If the The unknownsizeallowed attribute is OPTIONAL. If the
unknownsizeallowed attribute is not used then that EBML Element is unknownsizeallowed attribute is not used then that EBML Element is
not allowed to use an unknown Element Data Size. not allowed to use an unknown Element Data Size.
11.1.5.11. recursive 11.1.5.11. recursive
A boolean to express if an EBML Element is permitted to be stored A boolean to express if an EBML Element is permitted to be stored
recursively. In this case the EBML Element MAY be stored within recursively. In this case the EBML Element MAY be stored within
another EBML Element that has the same Element ID. Which itself can another EBML Element that has the same Element ID. Which itself can
be stored in an EBML Element that has the same Element ID, and so on. be stored in an EBML Element that has the same Element ID, and so on.
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The unknownsizeallowed attribute is OPTIONAL. If the The unknownsizeallowed attribute is OPTIONAL. If the
unknownsizeallowed attribute is not used then that EBML Element is unknownsizeallowed attribute is not used then that EBML Element is
not allowed to use an unknown Element Data Size. not allowed to use an unknown Element Data Size.
11.1.5.11. recursive 11.1.5.11. recursive
A boolean to express if an EBML Element is permitted to be stored A boolean to express if an EBML Element is permitted to be stored
recursively. In this case the EBML Element MAY be stored within recursively. In this case the EBML Element MAY be stored within
another EBML Element that has the same Element ID. Which itself can another EBML Element that has the same Element ID. Which itself can
be stored in an EBML Element that has the same Element ID, and so on. be stored in an EBML Element that has the same Element ID, and so on.
EBML Elements that are not Master Elements MUST NOT set recursive to EBML Elements that are not Master Elements MUST NOT set recursive to
true. true.
If the path contains an EBMLPathAtomRecursive part then the recursive If the path contains an EBMLPathAtomRecursive part then the recursive
value MUST be true and false otherwise. value MUST be true and false otherwise.
An EBML Element with the recursive attribute set to 1 MUST NOT have
its unknownsizeallowed attribute set to 1.
The recursive attribute is OPTIONAL. If the recursive attribute is The recursive attribute is OPTIONAL. If the recursive attribute is
not present then the EBML Element MUST NOT be used recursively. not present then the EBML Element MUST NOT be used recursively.
11.1.5.12. recurring 11.1.5.12. recurring
A boolean to express if an EBML Element is defined as an Identically A boolean to express if an EBML Element is defined as an Identically
Recurring Element or not. Recurring Element or not.
The recurring attribute is OPTIONAL. If the recurring attribute is The recurring attribute is OPTIONAL. If the recurring attribute is
not present then the EBML Element is not an Identically Recurring not present then the EBML Element is not an Identically Recurring
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that represents the last or most recent version of the docType to that represents the last or most recent version of the docType to
support the element. maxver MUST be greater than or equal to minver. support the element. maxver MUST be greater than or equal to minver.
The maxver attribute is OPTIONAL. If the maxver attribute is not The maxver attribute is OPTIONAL. If the maxver attribute is not
present then the EBML Element has a maximum version equal to the present then the EBML Element has a maximum version equal to the
value stored in the version attribute of "<EBMLSchema>". value stored in the version attribute of "<EBMLSchema>".
11.1.6. <documentation> Element 11.1.6. <documentation> Element
The "<documentation>" element provides additional information about The "<documentation>" element provides additional information about
the EBML Element. the EBML Element. Within the "<documentation>" element the following
XHTML [W3C.SPSD-xhtml-basic-20180327] elements MAY be used: "<a>",
"<br>", "<strong>".
11.1.7. <documentation> Attributes 11.1.7. <documentation> Attributes
11.1.7.1. lang 11.1.7.1. lang
A lang attribute which is set to the [RFC5646] value of the language A lang attribute which is set to the [RFC5646] value of the language
of the element's documentation. of the element's documentation.
The lang attribute is OPTIONAL. The lang attribute is OPTIONAL.
11.1.7.2. purpose 11.1.7.2. purpose
A purpose attribute distinguishes the meaning of the documentation. A purpose attribute distinguishes the meaning of the documentation.
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11.1.7.1. lang 11.1.7.1. lang
A lang attribute which is set to the [RFC5646] value of the language A lang attribute which is set to the [RFC5646] value of the language
of the element's documentation. of the element's documentation.
The lang attribute is OPTIONAL. The lang attribute is OPTIONAL.
11.1.7.2. purpose 11.1.7.2. purpose
A purpose attribute distinguishes the meaning of the documentation. A purpose attribute distinguishes the meaning of the documentation.
Values for the sub-element's purpose attribute MUST include one of Values for the "<documentation>" sub-element's purpose attribute MUST
the following: "definition", "rationale", "usage notes", and include one of the following: "definition", "rationale", "usage
"references". notes", and "references".
The purpose attribute is REQUIRED. The purpose attribute is REQUIRED.
11.1.8. <restriction> Element 11.1.8. <implementation_note> Element
In some cases within an EBML Document Type, the attributes of the
"<element>" element are not sufficient to clearly communicate how the
defined EBML Element is intended to be implemented. For instance,
one EBML Element might only be mandatory if another EBML Element is
present, or as another example, the default value of an EBML Element
might derive from a related Element's content. In these cases where
the Element's definition is conditional or advanced implementation
notes are needed, one or many "<implementation_note>" elements can be
used to store that information. The "<implementation_note>" refer to
a specific attribute of the parent "<element>" as expressed by the
"note_type" attribute Section 11.1.9.1.
11.1.9. <implementation_note> Attributes
11.1.9.1. note_type
The note_type attribute references which of the "<element>"'s
attributes that the implementation_note is in regards to. The
note_type attribute MUST be set to one of the following values
(corresponding to that attribute of the parent "<element>"):
"minOccurs", "maxOccurs", "range", "length", "default", "minver", or
"maxver". The "<implementation_note>" SHALL supersede the parent
"<element>"'s attribute that is named in the "note_type" attribute.
An "<element>" SHALL NOT have more than one "<implementation_note>"
of the same "note_type".
The note_type attribute is REQUIRED.
11.1.10. <restriction> Element
The "<restriction>" element provides information about restrictions The "<restriction>" element provides information about restrictions
to the allowable values for the EBML Element which are listed in to the allowable values for the EBML Element which are listed in
"<enum>" elements. "<enum>" elements.
11.1.9. <enum> Element 11.1.11. <enum> Element
The "<enum>" element stores a list of values allowed for storage in The "<enum>" element stores a list of values allowed for storage in
the EBML Element. The values MUST match the type of the EBML Element the EBML Element. The values MUST match the type of the EBML Element
(for example "<enum value="Yes">" cannot be a valid value for a EBML (for example "<enum value="Yes">" cannot be a valid value for a EBML
Element that is defined as an unsigned integer). An "<enum>" element Element that is defined as an unsigned integer). An "<enum>" element
MAY also store "<documentation>" elements to further describe the MAY also store "<documentation>" elements to further describe the
"<enum>". "<enum>".
11.1.10. <enum> Attributes 11.1.12. <enum> Attributes
11.1.10.1. label 11.1.12.1. label
The label provides a concise expression for human consumption that The label provides a concise expression for human consumption that
describes what the value of the "<enum>" represents. describes what the value of the "<enum>" represents.
The label attribute is OPTIONAL. The label attribute is OPTIONAL.
11.1.10.2. value 11.1.12.2. value
The value represents data that MAY be stored within the EBML Element. The value represents data that MAY be stored within the EBML Element.
The value attribute is REQUIRED. The value attribute is REQUIRED.
11.1.11. XML Schema for EBML Schema 11.1.13. <extension> Element
The "<extension>" element provides an unconstrained element to
contain information about the associated EBML "<element>" which is
undefined by this document but MAY be defined by the associated EBML
Document Type. The "<extension>" element MUST contain a "type"
attribute and also MAY contain any other attribute or sub-element as
long as the EBML Schema remains as a well-formed XML Document. All
"<extension>" elements MUST be sub-elements of the "<element>".
11.1.14. <extension> Attributes
11.1.14.1. type
The type attribute should reference a name or identifier of the
project or authority associated with the contents of the
"<extension>" element.
The type attribute is REQUIRED.
11.1.15. XML Schema for EBML Schema
This following provides an XML Schema [W3C.REC-xmlschema-0-20041028]
for facilitating verification of an EBML Schema to the definition
described in Section 8.1.
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns="https://ietf.org/cellar/ebml" <xs:schema xmlns="https://ietf.org/cellar/ebml"
targetNamespace="https://ietf.org/cellar/ebml" targetNamespace="https://ietf.org/cellar/ebml"
xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xhtml="http://www.w3.org/1999/xhtml"
elementFormDefault="qualified" version="01"> elementFormDefault="qualified" version="01">
<xsd:element name="EBMLSchema" type="EBMLSchemaType"/>
<xsd:complexType name="EBMLSchemaType"> <!-- for HTML in comments -->
<xsd:sequence> <xs:import namespace="http://www.w3.org/1999/xhtml"
<xsd:element name="element" type="elementType" minOccurs="0" schemaLocation="http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd"/>
maxOccurs="unbounded"/>
</xsd:sequence> <xs:element name="EBMLSchema" type="EBMLSchemaType"/>
<xsd:attribute name="docType" use="required"/>
<xsd:attribute name="version" use="required"/> <xs:complexType name="EBMLSchemaType">
</xsd:complexType> <xs:sequence>
<xsd:complexType name="elementType"> <xs:element name="element" type="elementType"
<xsd:sequence>
<xsd:element name="documentation" type="documentationType"
minOccurs="0" maxOccurs="unbounded"/> minOccurs="0" maxOccurs="unbounded"/>
<xsd:element name="restriction" type="restrictionType" </xs:sequence>
<xs:attribute name="docType" use="required"/>
<xs:attribute name="version" use="required"/>
</xs:complexType>
<xs:complexType name="elementType">
<xs:sequence>
<xs:element name="documentation" type="documentationType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="implementation_note" type="noteType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="restriction" type="restrictionType"
minOccurs="0" maxOccurs="1"/> minOccurs="0" maxOccurs="1"/>
</xsd:sequence> <xs:element name="extension" type="extensionType"
<xsd:attribute name="name" use="required"/>
<xsd:attribute name="path" use="required"/>
<xsd:attribute name="id" use="required"/>
<xsd:attribute name="minOccurs" default="0"/>
<xsd:attribute name="maxOccurs" default="1"/>
<xsd:attribute name="range"/>
<xsd:attribute name="length"/>
<xsd:attribute name="default"/>
<xsd:attribute name="type" use="required"/>
<xsd:attribute name="unknownsizeallowed"/>
<xsd:attribute name="recursive"/>
<xsd:attribute name="minver" default="1"/>
<xsd:attribute name="maxver"/>
</xsd:complexType>
<xsd:complexType name="restrictionType">
<xsd:sequence>
<xsd:element name="enum" type="enumType" minOccurs="0"
maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="enumType">
<xsd:sequence>
<xsd:element name="documentation" type="documentationType"
minOccurs="0" maxOccurs="unbounded"/> minOccurs="0" maxOccurs="unbounded"/>
</xsd:sequence> </xs:sequence>
<xsd:attribute name="label"/> <xs:attribute name="name" use="required"/>
<xsd:attribute name="value" use="required"/> <xs:attribute name="path" use="required"/>
</xsd:complexType> <xs:attribute name="id" use="required"/>
<xsd:complexType name="documentationType" mixed="true"> <xs:attribute name="minOccurs" default="0"/>
<xsd:sequence> <xs:attribute name="maxOccurs" default="1"/>
<xsd:any namespace="##any" minOccurs="0" maxOccurs="unbounded"/> <xs:attribute name="range"/>
</xsd:sequence> <xs:attribute name="length"/>
<xsd:attribute name="lang"/> <xs:attribute name="default"/>
<xsd:attribute name="purpose" use="required"> <xs:attribute name="type" use="required"/>
<xsd:simpleType> <xs:attribute name="unknownsizeallowed"/>
<xsd:restriction base="xsd:string"> <xs:attribute name="recurring"/>
<xsd:enumeration value="definition"/> <xs:attribute name="minver" default="1"/>
<xsd:enumeration value="rationale"/> <xs:attribute name="maxver"/>
<xsd:enumeration value="references"/> </xs:complexType>
<xsd:enumeration value="usage notes"/>
</xsd:restriction>
</xsd:simpleType>
</xsd:attribute>
</xsd:complexType>
</xsd:schema>
11.1.12. Identically Recurring Elements <xs:complexType name="restrictionType">
<xs:sequence>
<xs:element name="enum" type="enumType"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="extensionType">
<xs:sequence>
<xs:any processContents="skip"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="type" use="required"/>
<xs:anyAttribute processContents="skip"/>
</xs:complexType>
<xs:complexType name="enumType">
<xs:sequence>
<xs:element name="documentation" type="documentationType"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="label"/>
<xs:attribute name="value" use="required"/>
</xs:complexType>
<xs:complexType name="documentationType" mixed="true">
<xs:sequence>
<xs:element name="a" type="xhtml:xhtml.a.type"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="br" type="xhtml:xhtml.br.type"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="strong" type="xhtml:xhtml.strong.type"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="lang"/>
<xs:attribute name="purpose" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="definition"/>
<xs:enumeration value="rationale"/>
<xs:enumeration value="references"/>
<xs:enumeration value="usage notes"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:complexType>
<xs:complexType name="noteType">
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute name="note_type" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="minOccurs"/>
<xs:enumeration value="maxOccurs"/>
<xs:enumeration value="range"/>
<xs:enumeration value="length"/>
<xs:enumeration value="default"/>
<xs:enumeration value="minver"/>
<xs:enumeration value="maxver"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:schema>
11.1.16. Identically Recurring Elements
An Identically Recurring Element is an EBML Element that MAY occur An Identically Recurring Element is an EBML Element that MAY occur
within its Parent Element more than once but that each recurrence within its Parent Element more than once but that each recurrence
within that Parent Element MUST be identical both in storage and within that Parent Element MUST be identical both in storage and
semantics. Identically Recurring Elements are permitted to be stored semantics. Identically Recurring Elements are permitted to be stored
multiple times within the same Parent Element in order to increase multiple times within the same Parent Element in order to increase
data resilience and optimize the use of EBML in transmission. For data resilience and optimize the use of EBML in transmission. For
instance a pertinent Top-Level Element could be periodically resent instance a pertinent Top-Level Element could be periodically resent
within a data stream so that an EBML Reader which starts reading the within a data stream so that an EBML Reader which starts reading the
stream from the middle could better interpret the contents. stream from the middle could better interpret the contents.
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long-term storage or transmission. If a Parent Element contains more long-term storage or transmission. If a Parent Element contains more
than one copy of an Identically Recurring Element which includes a than one copy of an Identically Recurring Element which includes a
CRC-32 Element as a Child Element then the first instance of the CRC-32 Element as a Child Element then the first instance of the
Identically Recurring Element with a valid CRC-32 value should be Identically Recurring Element with a valid CRC-32 value should be
used for interpretation. If a Parent Element contains more than one used for interpretation. If a Parent Element contains more than one
copy of an Identically Recurring Element which does not contain a copy of an Identically Recurring Element which does not contain a
CRC-32 Element or if CRC-32 Elements are present but none are valid CRC-32 Element or if CRC-32 Elements are present but none are valid
then the first instance of the Identically Recurring Element should then the first instance of the Identically Recurring Element should
be used for interpretation. be used for interpretation.
11.1.13. Textual expression of floats 11.1.17. Textual expression of floats
When a float value is represented textually in an EBML Schema, such When a float value is represented textually in an EBML Schema, such
as within a default or range value, the float values MUST be as within a default or range value, the float values MUST be
expressed as Hexadecimal Floating-Point Constants as defined in the expressed as Hexadecimal Floating-Point Constants as defined in the
C11 standard [ISO.9899.2011] (see section 6.4.4.2 on Floating C11 standard [ISO.9899.2011] (see section 6.4.4.2 on Floating
Constants). The following table provides examples of expressions of Constants). The following table provides examples of expressions of
float ranges. float ranges.
+-------------------+-----------------------------------------+ +-------------------+-----------------------------------------+
| as decimal | as Hexadecimal Floating-Point Constants | | as decimal | as Hexadecimal Floating-Point Constants |
skipping to change at page 28, line 35 skipping to change at page 32, line 13
(hyphen) character is the separator between the minimal and maximum (hyphen) character is the separator between the minimal and maximum
value permitted by the range. Hexadecimal Floating-Point Constants value permitted by the range. Hexadecimal Floating-Point Constants
also use a - (hyphen) when indicating a negative binary power. also use a - (hyphen) when indicating a negative binary power.
Within a float range, when a - (hyphen) is immediately preceded by a Within a float range, when a - (hyphen) is immediately preceded by a
letter p, then the - (hyphen) is a part of the Hexadecimal Floating- letter p, then the - (hyphen) is a part of the Hexadecimal Floating-
Point Constant which notes negative binary power. Within a float Point Constant which notes negative binary power. Within a float
range, when a - (hyphen) is not immediately preceded by a letter p, range, when a - (hyphen) is not immediately preceded by a letter p,
then the - (hyphen) represents the separator between the minimal and then the - (hyphen) represents the separator between the minimal and
maximum value permitted by the range. maximum value permitted by the range.
11.1.14. Note on the use of default attributes to define Mandatory EBML 11.1.18. Note on the use of default attributes to define Mandatory EBML
Elements Elements
If a Mandatory EBML Element has a default value declared by an EBML If a Mandatory EBML Element has a default value declared by an EBML
Schema and the value of the EBML Element is equal to the declared Schema and the value of the EBML Element is equal to the declared
default value then that EBML Element is not required to be present default value then that EBML Element is not required to be present
within the EBML Document if its Parent Element is present. In this within the EBML Document if its Parent Element is present. In this
case, the default value of the Mandatory EBML Element MUST be read by case, the default value of the Mandatory EBML Element MUST be read by
the EBML Reader although the EBML Element is not present within its the EBML Reader although the EBML Element is not present within its
Parent Element. Parent Element.
skipping to change at page 33, line 45 skipping to change at page 37, line 41
id 0x4283 id 0x4283
minOccurs: 1 minOccurs: 1
maxOccurs: 1 maxOccurs: 1
length: >0 length: >0
type: String type: String
description: The name of the DocTypeExtension to identify it from description: The name of the DocTypeExtension to differentiate it
other DocTypeExtension of the same DocType+DocTypeVersion tuple. A from other DocTypeExtension of the same DocType+DocTypeVersion tuple.
DocTypeExtensionName value MUST be unique within the EBML Header. A DocTypeExtensionName value MUST be unique within the EBML Header.
11.2.11. DocTypeExtensionVersion Element 11.2.11. DocTypeExtensionVersion Element
name: DocTypeExtensionVersion name: DocTypeExtensionVersion
path: "1*1(\EBML\DocTypeExtension\Version)" path: "1*1(\EBML\DocTypeExtension\Version)"
id 0x4284 id 0x4284
minOccurs: 1 minOccurs: 1
maxOccurs: 1 maxOccurs: 1
range: not 0 range: not 0
type: Unsigned Integer type: Unsigned Integer
description: The version of the DocTypeExtension. Different description: The version of the DocTypeExtension. Different
DocTypeExtensionVersion values of the same DocTypeExtensionVersion values of the same
skipping to change at page 35, line 42 skipping to change at page 39, line 35
If a Master Element contains a CRC-32 Element that doesn't validate, If a Master Element contains a CRC-32 Element that doesn't validate,
then the EBML Reader MAY ignore all contained data except for then the EBML Reader MAY ignore all contained data except for
Descendant Elements that contain their own valid CRC-32 Element. Descendant Elements that contain their own valid CRC-32 Element.
If a Master Element contains more occurrences of a Child Master If a Master Element contains more occurrences of a Child Master
Element than permitted according to the maxOccurs and recurring Element than permitted according to the maxOccurs and recurring
attributes of the definition of that Element then the occurrences in attributes of the definition of that Element then the occurrences in
addition to maxOccurs MAY be ignored. addition to maxOccurs MAY be ignored.
If a Master Element contains more occurrences of a Child Element that If a Master Element contains more occurrences of a Child Element than
is not a Master Element than permitted according to the maxOccurs permitted according to the maxOccurs attribute of the definition of
attribute of the definition of that Element then all but the instance that Element then all instances of that Element after the first
of that Element with the smallest byte offset from the beginning of maxOccur occurrences from the beginning of its Parent Element SHOULD
its Parent Element SHOULD be ignored. be ignored.
13. Terminating Elements 13. Terminating Elements
Null Octets, which are octets with all bits set to zero, MAY follow Null Octets, which are octets with all bits set to zero, MAY follow
the value of a String Element or UTF-8 Element to serve as a the value of a String Element or UTF-8 Element to serve as a
terminator. An EBML Writer MAY terminate a String Element or UTF-8 terminator. An EBML Writer MAY terminate a String Element or UTF-8
Element with Null Octets in order to overwrite a stored value with a Element with Null Octets in order to overwrite a stored value with a
new value of lesser length while maintaining the same Element Data new value of lesser length while maintaining the same Element Data
Size (this can prevent the need to rewrite large portions of an EBML Size (this can prevent the need to rewrite large portions of an EBML
Document); otherwise the use of Null Octets within a String Element Document); otherwise the use of Null Octets within a String Element
skipping to change at page 40, line 21 skipping to change at page 44, line 10
o Missing EBML Elements that are mandatory in a Master Element and o Missing EBML Elements that are mandatory in a Master Element and
have no declared default value, making the semantic invalid at have no declared default value, making the semantic invalid at
that Master Element level. that Master Element level.
o Usage of invalid UTF-8 encoding in EBML Elements of UTF-8 type o Usage of invalid UTF-8 encoding in EBML Elements of UTF-8 type
(e.g. in order to trigger access-out-of-bounds or buffer overflow (e.g. in order to trigger access-out-of-bounds or buffer overflow
issues). issues).
o Usage of invalid data in EBML Elements with a date type, o Usage of invalid data in EBML Elements with a date type,
trigerring bogus date accesses. triggering bogus date accesses.
Side channel attacks could exploit: Side channel attacks could exploit:
o The semantic equivalence of the same string stored in a String o The semantic equivalence of the same string stored in a String
Element or UTF-8 Element with and without zero-bit padding, making Element or UTF-8 Element with and without zero-bit padding, making
comparison at the semantic level invalid. comparison at the semantic level invalid.
o The semantic equivalence of VINT_DATA within Element Data Size o The semantic equivalence of VINT_DATA within Element Data Size
with two different lengths due to left-padding zero bits, making with two different lengths due to left-padding zero bits, making
comparison at the semantic level invalid. comparison at the semantic level invalid.
skipping to change at page 40, line 46 skipping to change at page 44, line 35
o Extraneous copies of Identically Recurring Element, making parsing o Extraneous copies of Identically Recurring Element, making parsing
unnecessarily slow to the point of not being usable. unnecessarily slow to the point of not being usable.
o Copies of Identically Recurring Element within a Parent Element o Copies of Identically Recurring Element within a Parent Element
that contain invalid CRC-32 Elements. EBML Readers not checking that contain invalid CRC-32 Elements. EBML Readers not checking
the CRC-32 might use the version of the element with mismatching the CRC-32 might use the version of the element with mismatching
CRC-32. CRC-32.
o Use of Void Elements which could be used to hide content or create o Use of Void Elements which could be used to hide content or create
bogus resynchronzation points seen by some EBML Reader and not bogus resynchronization points seen by some EBML Reader and not
others. others.
An EBML Reader MAY use the data if it considers it doesn't create any
security issue.
17. IANA Considerations 17. IANA Considerations
17.1. CELLAR EBML Element ID Registry 17.1. CELLAR EBML Element ID Registry
This document creates a new IANA Registry called "CELLAR EBML Element This document creates a new IANA Registry called "CELLAR EBML Element
ID Registry". ID Registry".
Element IDs are described in section Element ID. Element IDs are Element IDs are described in section Element ID. Element IDs are
encoded using the VINT mechanism described in section Section 4 can encoded using the VINT mechanism described in section Section 4 can
be between one and five octets long. Five octet long Element IDs are be between one and five octets long. Five octet long Element IDs are
skipping to change at page 41, line 44 skipping to change at page 45, line 29
and 0x1FFFFE. Numbers may be allocated within this range according and 0x1FFFFE. Numbers may be allocated within this range according
to the "First Come First Served" policy [RFC8126]. to the "First Come First Served" policy [RFC8126].
The numbers 0x1FFFFF and 0x200000 are RESERVED. The numbers 0x1FFFFF and 0x200000 are RESERVED.
Four-octet Element IDs are numbers between 0x101FFFFF and 0x1FFFFFFE. Four-octet Element IDs are numbers between 0x101FFFFF and 0x1FFFFFFE.
Four-octet Element IDs are somewhat special in that they are useful Four-octet Element IDs are somewhat special in that they are useful
for resynchronizing to major structures in the event of data for resynchronizing to major structures in the event of data
corruption or loss. As such four-octet Element IDs are split into corruption or loss. As such four-octet Element IDs are split into
two categories. Four-octet Element IDs whose lower three octets (as two categories. Four-octet Element IDs whose lower three octets (as
encoded) would make printable 7-bit ASCII values (0x20 to 0x7F) MUST encoded) would make printable 7-bit ASCII values (0x20 to 0x7E,
be allocated by the "Specification Required" policy. Sequential inclusive) MUST be allocated by the "Specification Required" policy.
allocation of values is not required: specifications SHOULD include a Sequential allocation of values is not required: specifications
specific request, and are encouraged to do early allocations. SHOULD include a specific request, and are encouraged to do early
allocations.
To be clear about the above category: four-octet Element IDs always To be clear about the above category: four-octet Element IDs always
start with hex 0x10 to 0x1F, and that octet may be chosen so that the start with hex 0x10 to 0x1F, and that octet may be chosen so that the
entire number has some desirable property, such as a specific CRC. entire number has some desirable property, such as a specific CRC.
The other three octets, when ALL having values between 0x21 (33, The other three octets, when ALL having values between 0x21 (33,
ASCII !) and 0x7E (126, ASCII ~), fall into this category. ASCII !) and 0x7E (126, ASCII ~), fall into this category.
Other four-octet Element IDs may be allocated by the "First Come Other four-octet Element IDs may be allocated by the "First Come
First Served" policy. First Served" policy.
The numbers 0xFFFFFFF and 0x1000000 are RESERVED. The numbers 0xFFFFFFF and 0x1000000 are RESERVED.
Five octet Element IDs (values from 0x10000001 upwards) are RESERVED Five octet Element IDs (values from 0x10000001 upwards) are RESERVED
according to the "Experimental Use" policy [RFC8126]: they may be according to the "Experimental Use" policy [RFC8126]: they may be
skipping to change at page 43, line 10 skipping to change at page 46, line 41
| | | 11.3.1 | | | | 11.3.1 |
| 0xEC | Void | Described in Section | | 0xEC | Void | Described in Section |
| | | 11.3.2 | | | | 11.3.2 |
+------------+-------------------------+----------------------------+ +------------+-------------------------+----------------------------+
17.2. CELLAR EBML DocType Registry 17.2. CELLAR EBML DocType Registry
This document creates a new IANA Registry called "CELLAR EBML DocType This document creates a new IANA Registry called "CELLAR EBML DocType
Registry". Registry".
To register a new DocType in this registry one needs a DocType name,
a Description of the DocType, a Change Controller (IESG or email of
registrant) and an optional Reference to a document describing the
DocType.
DocType values are described in Section 11.1.3.1. DocTypes are ASCII DocType values are described in Section 11.1.3.1. DocTypes are ASCII
strings, defined in Section 7.4, which label the official name of the strings, defined in Section 7.4, which label the official name of the
EBML Document Type. The strings may be allocated according to the EBML Document Type. The strings may be allocated according to the
"First Come First Served" policy. "First Come First Served" policy.
The use of ASCII corresponds to the types and code already in use, The use of ASCII corresponds to the types and code already in use,
the value is not meant to be visible to the user. the value is not meant to be visible to the user.
DocType string values of "matroska" and "webm" are RESERVED to the DocType string values of "matroska" and "webm" are RESERVED to the
IETF for future use. These can be assigned via the "IESG Approval" IETF for future use. These can be assigned via the "IESG Approval"
skipping to change at page 44, line 42 skipping to change at page 48, line 29
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[W3C.REC-xml-20081126] [W3C.REC-xml-20081126]
Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", World Wide Web Consortium Recommendation REC- Edition)", World Wide Web Consortium Recommendation REC-
xml-20081126, November 2008, xml-20081126, November 2008,
<http://www.w3.org/TR/2008/REC-xml-20081126>. <http://www.w3.org/TR/2008/REC-xml-20081126>.
[W3C.SPSD-xhtml-basic-20180327]
McCarron, S., "XHTMLa&#132;[cents] Basic 1.1 - Second
Edition", World Wide Web Consortium Recommendation SPSD-
xhtml-basic-20180327, March 2018,
<http://www.w3.org/TR/2018/SPSD-xhtml-basic-20180327>.
18.2. Informative References 18.2. Informative References
[W3C.REC-xmlschema-0-20010502] [W3C.REC-xmlschema-0-20041028]
Fallside, D., "XML Schema Part 0: Primer", World Wide Web Fallside, D. and P. Walmsley, "XML Schema Part 0: Primer
Consortium Recommendation REC-xmlschema-0-20010502, May Second Edition", World Wide Web Consortium Recommendation
2001, REC-xmlschema-0-20041028, October 2004,
<http://www.w3.org/TR/2001/REC-xmlschema-0-20010502>. <http://www.w3.org/TR/2004/REC-xmlschema-0-20041028>.
18.3. URIs 18.3. URIs
[1] https://github.com/Matroska-Org/matroska-specification/ [1] https://github.com/Matroska-Org/matroska-specification/
Authors' Addresses Authors' Addresses
Steve Lhomme Steve Lhomme
Email: slhomme@matroska.org Email: slhomme@matroska.org
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