Overview
ISO/IEC 23008-5:2017 - Information technology: High efficiency coding and media delivery in heterogeneous environments - Part 5 - provides the reference software accompanying Rec. ITU‑T H.265 | ISO/IEC 23008‑2 (commonly known as H.265 or HEVC). The document includes an electronic attachment containing encoder and decoder source implementations (reference software) intended as a study, testing and implementation aid. The standard clarifies that requirements in Rec. ITU‑T H.265 / ISO/IEC 23008‑2 take precedence over the behaviour of the reference software.
Key topics and requirements
- Reference software package: The attached software comprises three components:
- HM (HEVC Model) - supports Main, Main 10, Main Still Picture and a wide range of 4:2:2 / 4:4:4 and monochrome profiles, including intra and High Throughput variants.
- SHM (Scalable HEVC Model) - supports Scalable Main and related scalable profiles.
- HTM (Multiview/3D HEVC Model) - supports Multiview Main and 3D Main profiles.
- Reference encoder and decoder: Implementations capable of producing and decoding bitstreams that conform to Rec. ITU‑T H.265 | ISO/IEC 23008‑2.
- Bitstream conformance & decoding process: The software can be used to detect many bitstream conformance violations and demonstrates the decoding process specified by H.265.
- Normative linkage: This part references and accompanies ISO/IEC 23008‑2 and Recommendation ITU‑T H.265 (2013).
- Limitations and legal notes:
- Use of the reference software is not required to build conformant encoders/decoders.
- Conformance of an encoder does not guarantee encoding quality; conformance is defined only by bitstream format and constraints.
- Patent and warranty disclaimers apply; commercial implementations may be subject to third‑party patents and royalties.
Applications and who uses it
- Standards developers and researchers: Study algorithmic behaviour, verify specified decoding/encoding processes, and reproduce reference results.
- Implementation engineers: Use the reference encoder/decoder as a starting point for production implementations or to validate interoperability.
- Conformance and QA teams: Generate test bitstreams, verify decoder conformance, and detect many bitstream violations.
- Academic and training: Educational demonstrations of HEVC concepts and expected decoding outputs.
- Test labs and device manufacturers: Compare outputs between implementations to ensure identical decoded sample values where required by profile/level.
Related standards
- Rec. ITU‑T H.265 (High efficiency video coding)
- ISO/IEC 23008‑2:2013 (Coding of audio‑visual objects - Part 2: High efficiency video coding)
Keywords: ISO/IEC 23008-5:2017, H.265, HEVC, reference software, encoder, decoder, bitstream conformance, HM, SHM, HTM, scalable HEVC, profiles.