Overview
ISO/IEC 13522-3:1997 - MHEG script interchange representation (MHEG‑SIR) - is part of the ISO/IEC 13522 family for coding multimedia and hypermedia information. First published in 1997, this part defines the script interchange model and runtime provisions that enable exchange, interpretation and execution of MHEG scripts between tools and MHEG‑3 engines. Key scope items include data types, declarations, virtual machine structure, conformance and runtime access to external services.
Key Topics and Technical Requirements
The standard organizes technical content around the MHEG‑SIR language and execution environment. Major topics covered include:
- Conformance: requirements for information object, implementation and application conformance; profiles, encoding, syntax and semantics; test methods.
- Language elements: declarations for types, constants, global/local variables, routines, services and messages.
- Data types: predefined primitive and constructed types (primitive types, string/sequence/array/structure/union types) and declared constructed types.
- Program elements: immediate values, constants, variables, routines, services, predefined functions and message/exception handling.
- Virtual machine model: structure of the MHEG‑SIR virtual machine, memory areas (code/data/heap), stacks, registers, queues and script statuses.
- Runtime environment access: general model for invoking external operations, IDL interface declaration, handling external exceptions and platform mapping considerations.
- MHEG object manipulation: invoking MHEG actions, message exchange between scripts and interaction with MHEG objects.
- Script interchange artifacts: package, service and handler definition tables; type and constant declaration formats.
Note: content items above are taken from the standard’s table of contents and describe the covered topics rather than implementation specifics.
Applications and Who Uses It
ISO/IEC 13522-3:1997 is intended for implementers and integrators who need portable, interoperable scripting for multimedia/hypermedia applications, including:
- MHEG‑3 engine developers (set‑top boxes, middleware)
- Interactive TV and digital broadcasting vendors
- Multimedia application developers who exchange scripts or need a standardized runtime model
- Test laboratories and QA teams validating conformance and interoperability
- Platform integrators mapping MHEG runtime calls to native services
Practical benefits include consistent script interchange between authoring tools and engines, clearer runtime semantics for message passing and exceptions, and a standard virtual machine model for predictable execution.
Related Standards
- Other parts of ISO/IEC 13522 (multimedia/hypermedia coding family)
- MHEG‑3 specifications and platform mapping documents (referenced for API and runtime integration)
Keywords: ISO/IEC 13522-3:1997, MHEG‑SIR, MHEG script, multimedia coding, hypermedia, script interchange, virtual machine, runtime environment, conformance.