Overview
ISO/IEC 23001-16:2021 - "Derived visual tracks in the ISO base media file format" defines a standardized storage format and base set of transformation operations for creating timed sequences of images derived from input still images or video samples in the same presentation. Built on the ISO Base Media File Format (ISO/IEC 14496-12), the standard specifies normative structures for describing transformation operations, linking those operations to inputs, and processing them to produce timed video frames suitable for interchange, editing and display.
Key topics and technical requirements
- Derived visual track structure: normative boxes and records to store descriptions of derivation operations, sample entries and configuration data.
- Derivation operations: an initial base set of transformations with defined syntax and semantics, including:
- Identity, sRGB Fill, Dissolve
- Crop, Rotation, Mirror, Scaling
- Region of Interest (ROI) selection
- Grid composition and Overlay composition
- Sample format and timing: how derived samples are represented and synchronized with source samples to produce timed sequences of frames.
- Linking and processing rules: mechanisms to link transformation descriptions to input images or video samples and the processing semantics to generate output frames.
- Interchange and editability: semantics designed to enable editing workflows, interchange between tools and deterministic playback.
- References and conformance: ties to ISO/IEC 14496-12 (ISO base media file format) and related standards; syntax and semantics are normative for conformance.
Applications and who uses it
- Media software developers: implementers of media players, editors, transcoders, and authoring tools use the standard to support derived visual tracks reliably.
- Streaming and broadcast: content packaging systems and streaming platforms can store visual transformations as part of media assets for client-side rendering or server-side processing.
- Post-production and editing: non-linear editors and workflow tools benefit from a standardized way to represent edits and compositions without re-encoding source media.
- Content providers and archives: enable efficient interchange of versioned or transformed visual content while preserving links to original assets.
- Device and client implementers: mobile and set-top box vendors that support deterministic rendering of derived visual tracks for consistent playback.
Related standards
ISO/IEC 23001-16 is essential for anyone implementing or using MPEG-based file formats who needs a standardized method to store, exchange and render image or video transformations as timed visual tracks.