ISO/IEC 23094-3:2022

Overview

ISO/IEC 23094-3:2022 - "Information technology - General video coding - Part 3: Conformance and reference software for low complexity enhancement video coding" defines the tests, procedures and reference software used to verify that bitstreams and decoders comply with the normative requirements of ISO/IEC 23094-2. The standard provides an electronic attachment with conformance and test bitstreams plus reference encoder/decoder code (LTM repository) to support objective conformance testing for low complexity enhancement video coding (LCEVC).

Key topics and technical requirements

• Conformance testing framework: Normative procedures to verify that bitstreams and decoders meet ISO/IEC 23094-2 requirements, including parsing and syntax checks using the provided test suites.
• Bitstream conformance: Tests that ensure a produced bitstream is syntactically correct and decodable by the reference software decoder; parsing the entire bitstream is required to validate syntax and element values.
• Decoder conformance: Procedures for validating decoder behavior and capabilities, including rules for which bitstreams a decoder must support based on profile_idc and level_idc.
• Test bitstreams and file contents: Conformance bitstreams are supplied as electronic attachments. Typical files include *.bit, *.cfg (encoder config), *.opl (output picture log), MD5 checksums, and decoded YUV MD5s to validate outputs.
• Operation modes for testing:
  • Mode A: Use the reference software decoder to extract decoded base pictures and feed those plus the enhancement bitstream to the decoder under test.
  • Mode B: Provide the full test bitstream directly to the decoder under test.
• Output conformance classes:
  • Output order conformance - decoded pictures must be output in the specified order and match reference sample values.
  • Output timing conformance - requirements for timing of decoded outputs (described in ISO/IEC 23094-2).
• Reference software and LTM repository: Reference encoder/decoder implementations and guidance for encoder/decoder usage are included to enable reproducible tests.
• Informative annexes: Guidance on accuracy tolerances for decoding implementations and demultiplexing of test bitstreams.

Practical applications / Who uses this standard

• Codec developers and implementers - validate that encoders generate conforming bitstreams and decoders meet expected capabilities.
• Interoperability test labs - perform formal conformance testing using supplied bitstream suites and reference software.
• Product validation and QA teams - regression testing and compliance verification for devices, streaming clients or media servers integrating LCEVC.
• Standards bodies and certification programs - base conformance criteria for certification of LCEVC implementations.

Related standards

• ISO/IEC 23094-2:2021 (Low complexity enhancement video coding) - normative behavioral and syntax requirements.
• Rec. ITU‑T H.264 | ISO/IEC 14496-10 (AVC) and Rec. ITU‑T H.265 | ISO/IEC 23008-2 (HEVC) - referenced for test base bitstreams.
• ISO/IEC 14882 - C++ (referenced for reference software development).

Keywords: ISO/IEC 23094-3:2022, general video coding, low complexity enhancement video coding, conformance testing, reference software, bitstream conformance, decoder conformance, LTM repository, test bitstreams.