Overview
ISO/IEC 21000-17:2006 - part of the MPEG-21 multimedia framework - defines a normative syntax for URI Fragment Identifiers to address parts of MPEG resources. It applies to resources whose Internet Media Type is audio/mpeg, video/mpeg, video/mp4, audio/mp4 and application/mp4 (RFC 3003, RFC 2045/2046, RFC 4337) and is compliant with IETF RFC 3986 (URIs) and RFC 3987 (IRIs). The specification builds on the W3C XPointer Framework and extends it to support precise addressing of temporal, spatial, spatiotemporal, logical and byte-range fragments of audiovisual content.
Key topics and technical requirements
- MPEG URI Fragment Identifier Framework: generic principles for combining pointer parts, using namespaces (xmlns()), character escaping, hierarchical pointer composition, and processing rules (based on XPointer).
- Pointer schemes (normative): defined pointer schemes include ffp(), offset(), mp(), and mask() for addressing fragments (e.g., byte ranges, items/tracks in ISO Base Media Files, and masked video regions).
- Fragment types supported:
- Temporal, spatial and spatiotemporal locations
- Logical units according to a Logical Model
- Byte ranges and offsets
- Items or tracks within ISO Base Media Files (MP4)
- Video portions via mask()
- Logical Model representation: XML Schema tools and schemas to describe logical structures of media resources, including a logical model for MPEG-4 files and schema-for-schemas support.
- Normative references: W3C XML/XPointer/XPath, ISO base media file format (ISO/IEC 14496-12), ISO 8601 time formats, and relevant RFCs for MIME and URIs.
Applications and who uses it
Practical uses of ISO/IEC 21000-17:2006 include:
- Precise linking and deep-linking to segments of audio/video on the web and in documentation.
- Media player and streaming platform implementations for navigation, seeking and segment delivery.
- Content annotation, indexing, search and metadata services that reference specific media fragments.
- Editing, transcoding and content-processing tools that must identify and operate on sub-portions of media files.
- Archival and preservation systems that reference regions (time/space/byte) within assets.
Typical users:
- Multimedia software developers, streaming CDN and player vendors
- Web developers and content platforms implementing deep links to media
- Media asset management and digital library teams
- Standards implementers and tool vendors needing interoperable fragment addressing
Related standards
- ISO/IEC 21000 (MPEG-21) family (Digital Item Declaration, Identification, File Format, etc.)
- W3C XPointer and XPath recommendations
- ISO/IEC 14496-12 (ISO base media file format)
- IETF RFC 3986, RFC 3987, RFC 4337, RFC 3003
Keywords: ISO/IEC 21000-17:2006, MPEG-21, Fragment Identification, URI fragment identifiers, MP4 fragments, temporal-spatial fragments, XPointer, mp4 byte ranges.