OEBPS Container Format (OCF) 1.0

 

Recommended Specification
 September 11, 2006

 

 

 

 

 

 

 

Copyright © 2006 by International Digital Publishing Forum™.

All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and dissemination of this work with changes is prohibited except with the written permission of the International Digital Publishing Forum.

TABLE OF CONTENTS

TABLE OF CONTENTS................................................................................................... ii

1    Overview.................................................................................................................. 1

1.1    Purpose and Scope.......................................................................................... 1

1.2    Definitions.......................................................................................................... 1

1.3    Relationship to Other Specifications.................................................... 3

1.4    Conformance.................................................................................................... 3

1.4.1   Conforming Containers...................................................................................... 4

1.4.2   Conforming Reading Systems............................................................................. 4

1.5    Accessibility...................................................................................................... 4

1.6    Future Directions........................................................................................... 5

2    OCF Overview......................................................................................................... 5

2.1    OCF: A General Container Technology.................................................. 5

2.2    “Abstract Container” vs. “Physical Container”............................... 5

2.3    Examples.............................................................................................................. 6

2.3.1   Example of a simple Publication, Abstract Container, and ZIP Container.......... 6

2.3.2   Single-publication containers, but with alternate renditions.............................. 7

3    OCF Container Contents................................................................................. 8

3.1    File and directory structure................................................................... 8

3.2    Relative IRIs for referencing other components............................ 9

3.3    File Names........................................................................................................... 9

3.4    Container media type identification................................................... 10

3.5    META-INF.............................................................................................................. 11

3.5.1   Container – META-INF/container.xml (Required)............................................ 11

3.5.2   Manifest – META-INF/manifest.xml (Optional)................................................. 13

3.5.3   Metadata – META-INF/metadata.xml (Optional).............................................. 13

3.5.4   Digital Signatures – META-INF/signatures.xml (Optional)............................... 13

3.5.5   Encryption – META-INF/encryption.xml (Optional)......................................... 15

3.5.6   Rights Management – META-INF/rights.xml (Optional)................................... 16

4    ZIP Container....................................................................................................... 17

APPENDIX A: RELAX NG OCF Schema................................................................... 19

APPENDIX B: Example............................................................................................... 20

APPENDIX C: CONTRIBUTORS................................................................................... 24

1         Overview

1.1        Purpose and Scope

This specification defines the OEBPS Container Format (OCF). OCF is a general-purpose container technology. This specification describes the general-purpose container technology in the context of encapsulating OEBPS publications and OPTIONAL alternate renditions thereof. It is however anticipated that the general-purpose container technology described herein will ultimately be used in other bundling applications.

As a general container format, OCF collects a related set of files into a single-file container. OCF can be used to collect files in various document formats and for classes of applications. The single-file container enables easy transport of, management of, and random access to, the collection.

OCF defines the rules for how to represent an abstract collection of files (the “abstract container”) into physical representation within a ZIP archive (the “physical container”). The rules for ZIP containers build upon and are backward compatible with the ZIP technologies used by Open Document Format (ODF) 1.0.  

OCF is the RECOMMENDED single-file container technology for OEBPS publications. OCF MAY play a role in the following workflows:

·         During the preparation steps in producing an electronic publication, OCF is used as the single-file format when exchanging in-progress publications between different individuals and/or different organizations.

·         When providing an electronic publication from publisher or conversion house (Content Provider) to the distribution or sales channel, OCF is the RECOMMENDED single-file format to be used as the transport format.

·         When delivering the final publication to an OCF Reading System or end-user, OCF is the RECOMMENDED format for the single-file container that holds all of the assets that make up the publication.

1.2        Definitions

ASCII

American Standard Code for Information Interchange – a 7-bit character encoding based on the English alphabet (ANSI X3.4-1986). When used in this document, ASCII refers to the printable graphic characters in the range 33 (decimal) through 126 (decimal) and the nonprintable space character 32 (decimal).

IRI

Internationalized Resource Identifier (http://www.ietf.org/rfc/rfc3987.txt).

OCF Container

A container file that is compliant with the format defined in this specification.

OCF

The OEBPS Container Format defined by this specification.

Content Provider

A publisher, author, individual, or other information source that provides a publication to distribution or sales channels or directly to one or more OCF Reading Systems using OCF as described in this specification.

ODF

Open Document Format (http://www.oasis-open.org/committees/download.php/12572/OpenDocument-v1.0-os.pdf).

OEBPS

Open eBook Publication Structure (http://www.idpf.org/oebps/oebps1.2/index.htm).

OEBPS Document

An XML markup document that conforms to the OEBPS 1.2 specification – generally containing textual content of an OEBPS Publication.

OEBPS Package

An XML file that describes an OEBPS Publication as defined by the OEBPS 1.2 specification. It identifies all other files in the publication and provides descriptive information about them.

OEBPS Publication

A collection of OEBPS Documents, an OEBPS Package file, and other files, typically in a variety of media types, including structured text and graphics that constitute a cohesive unit for publication, as defined by the OEBPS 1.2 specification.

OCF Reading System

A combination of hardware and/or software that accepts OEBPS Publications (packaged in an OCF Container) and makes them available to consumer of the content. Great variety is possible in the architecture of OCF Reading Systems. An OCF Reading System MAY be implemented entirely on one device, or it MAY be split among several computers. In particular, a reading device that is a component of a OCF Reading System need not directly accept OCF Packaged OEBPS Publications, but all OCF Reading Systems MUST do so. OCF Reading Systems MAY include additional processing functions, such as compression, indexing, encryption, rights management, and distribution.

MIME

Multipurpose Internet Mail Extensions (http://www.isi.edu/in-notes/rfc2045.txt).  “MIME media types” provide a standard methodology for specifying the content type of objects.

RFC

Literally “Request For Comments”, but more generally a document published by the Internet Engineering Task Force (IETF). See http://www.ietf.org/rfc.html.

Relax NG

A schema language for XML (http://www.relaxng.org/).

Rootfile

The top-level file of a rendition of a publication; either the “root” from which all other components can be found or the lone file encapsulating the rendition.  The OEBPS rootfile is the OEBPS Package file.  A PDF file containing the PDF rendition could also be a rootfile.

XML

Extensible Markup Language (http://www.w3.org/TR/xml11/).

ZIP

A defacto industry standard bundling and compression format (http://www.pkware.com/business_and_developers/developer/appnote).

1.3           Relationship to Other Specifications

This specification combines subsets and applications of other specifications. Together, these facilitate the construction, organization, presentation, and unambiguous interchange of electronic documents:

  1. The XML 1.1 Extensible Markup Language specification (http://www.w3.org/TR/xml11/); and
  2. The OEBPS 1.2 Open eBook Publication Structure specification (http://www.idpf.org/oebps/oebps1.2/index.htm); and
  3. The XML 1.1 namespace specification ( http://www.w3.org/TR/xml-names11/); and
  4. The Unicode Standard, Version 4.0. Reading, Mass.: Addison-Wesley, 2003, as updated from time to time by the publication of new versions. (See  http://www.unicode.org/unicode/standard/versions for the latest version and additional information on versions of the standard and of the Unicode Character Database).; and
  5. Particular MIME media types (http://www.ietf.org/rfc/rfc4288.txt and http://www.iana.org/assignments/media-types/index.html); and
  6. Open Document Format for Office Applications (Open Document) v1.0 (http://www.oasis-open.org/committees/download.php/12572/OpenDocument-v1.0-os.pdf); and
  7. ZIP format (http://www.pkware.com/business_and_developers/developer/appnote); and
  8. XML-Signature Syntax and Processing (http://www.w3.org/TR/2002/REC-xmldsig-core-20020212); and
  9. XML Encryption Syntax and Processing (http://www.w3.org/TR/2002/REC-xmlenc-core-20021210).
  10. Web Content Accessibility Guidelines 1.0 (http://www.w3.org/TR/WCAG10/).

1.4        Conformance

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "RECOMMENDED", "MAY", and "OPTIONAL" in this document MUST be interpreted as described in (http://www.ietf.org/rfc/rfc2119.txt).

This section defines conformance requirements for OCF.

1.4.1        Conforming Containers

The term “Conforming OCF Abstract Container” indicates an OCF Abstract Container (See Section 2.2) that conforms to all of the relevant conformance criteria defined in this specification. The term “Conforming OCF ZIP Container” indicates a ZIP archive that conforms to the relevant ZIP container conformance criteria (See Section 4) and whose contents is a Conforming OCF Abstract Container.

In addition to other conformance criteria defined in this specification, a Conforming OCF Abstract Container MUST meet the following conditions:

·         All XML files MUST be well-formed (as defined in XML 1.1) and thus include a correct XML declaration (e.g. <?xml version=’1.0’?>)

·         All XML files MUST be compatible with the XML 1.1 specification (http://www.w3.org/TR/2004/REC-xml11-20040204) and the Namespaces in XML specification (http://www.w3.org/TR/REC-xml-names