Overview - ISO/IEC 23001-11:2023 (green metadata)
ISO/IEC 23001-11:2023, "Information technology - MPEG systems technologies - Part 11: Energy-efficient media consumption (green metadata)," specifies a metadata framework that enables reduced energy use during media consumption. The standard defines formats and semantics for metadata used to reduce decoder power, display power, and to support energy-aware media selection and quality recovery after low‑power encoding. It is the third edition (2023), updating the 2019 edition with new VVC SEI messages and finer interactive signalling for encoder/decoder control.
Key topics and technical requirements
- Green metadata formats: Defines metadata structures for energy-efficient decoding, encoding, presentation, and selection of media.
- Decoder power reduction: Introduces complexity metrics (CM) metadata and decoding operation reduction request (DOR‑Req) metadata. CM helps decoders adapt operating frequency; DOR‑Req allows remote encoders to request lower-complexity encoding.
- Interactive signalling: Syntax and semantics for signalling between decoder and encoder to request or negotiate power-saving decoding operations.
- Display power reduction: Metadata (including RGB-component statistics and quality levels) for display subsystems to dynamically adapt presentation parameters and lower display energy use.
- Energy‑efficient media selection: Metadata that assists clients (e.g., adaptive streaming clients) to choose video representations that optimize the tradeoff between power savings and quality of experience (QoE).
- Quality recovery metrics: Metrics and metadata to support restoration of quality after low‑power encoding; includes syntax for AVC/HEVC and VVC SEI messages.
- Conformance and implementation guidance: Clauses and annexes for conformance, reference software, SEI syntax, implementation guidelines, and objective distortion metrics.
Practical applications and who uses this standard
- Streaming platforms and CDN providers: to offer energy‑aware bitrate/representation selection for mobile or battery‑constrained clients.
- Codec and encoder vendors: to implement DOR‑Req and CM signalling in encoders and bitstreams (AVC, HEVC, VVC).
- Decoder and SoC manufacturers: to adapt decoder frequency/power based on CM metadata for lower power consumption.
- Display and device manufacturers: to use RGB statistics and quality levels for display-adaptive power savings.
- Video conferencing and real‑time communication systems: to enable remote low‑complexity encoding for participant devices with power constraints.
- Standards engineers and researchers: for integration, conformance testing, and developing energy‑efficient media workflows.
Related standards (normative references)
This standard is essential for implementing energy-efficient media consumption, enabling interoperable metadata-driven strategies across encoders, decoders, displays, and adaptive streaming clients.
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