GB/T 46271-2025Information technology — 3D audio technology — Coding, distribution and presentation (English PDF)
信息技术 三维声技术 编码、分发与呈现
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Issued by
SAMR; SAC
Level / Type
National · Recommended
Issue date
August 29, 2025
Implementation date
March 1, 2026
Scope
GB/T 46271-2025 is the English-translated version of 信息技术 三维声技术 编码、分发与呈现.
GB/T 46271-2025 is the Chinese national standard covering the Chinese 3D audio format for broadcast, streaming, real-time communication and virtual reality — the coding and rendering framework, the full-bitrate decoder with its neural network inverse transform, bandwidth extension and noise shaping, the higher-order ambisonic spatial decoding, the lossless path, and the static and dynamic metadata carrying object positions, loudness, acoustic environment and the interaction a listener is allowed. At 185,000 words. The codec clauses carry patents declared by Huawei and offered on reasonable and non-discriminatory terms. First edition, in force from 1 March 2026. Issued on 29 August 2025, it has been in force since 1 March 2026.
Document preview — GB/T 46271-2025
National Standard of the People's Republic of China
- ICS
- 35.040
- Classification
- L 71
Issued by: State Administration for Market Regulation; Standardization Administration of the PRC
Contents
- PrefaceV
- IntroductionVI
- 1 Scope1
- 2 Normative References1
- 3 Terms and Definitions1
- 4 Abbreviations2
- 5 Agreement3
- 5.1 Arithmetic Operators3
- 5.2 Logical Operators3
- 5.3 Relational Operators4
- 5.4 Bitwise Operators4
- 5.5 Assignment Operators4
- 5.6 Mnemonics5
- 5.7 Mathematical Functions5
- 5.8 Bitstream Syntax Rules5
- 6.3D sound encoding/decoding and rendering framework 7.9
- 7 Universal Full Bitrate Audio Decoding9
- 7.1 Overview9
- 7.2 Bitstream Demultiplexing Syntax and Semantics and Decoding Process15
- 7.3 Interval Decoding, Inverse Quantization, and Neural Network Inverse Transform Syntax and Semantics and Decoding Process20
- 7.4 Syntax, Semantics, and Decoding Process of Spectrum Inverse Grouping24
- 7.5 Two-channel stereo bit allocation and upmixing syntax and decoding process25
- 7.6 Multichannel bit allocation and upmixing syntax and semantics and decoding process30
- 7.7 HOA Bit Allocation and Upmixing32
- 7.8 Post-decoding processing syntax and semantics and the decoding process36
- 7.9 Bandwidth Spread Decoding Syntax and Semantics and Decoding Process37
- 7.10 Inverse Time Domain Noise Shaping Syntax, Semantics, and Decoding Process45
- 7.11 Inverse Frequency Domain Noise Shaping Syntax, Semantics, and Decoding Process47
- 7.12 Inverse MDCT Decoding Process49
- 7.13 HOA Spatial Decoding50
- 8 Lossless audio decoding55
- 9 Metadata Decoding55
- 9.1 Metadata Bitstream Syntax and Semantics55
- 9.2 Static Metadata Decoding Syntax and Semantics56
- 9.3 Dynamic Metadata Decoding Syntax and Semantics57
- 9.4 Basic Static Metadata Decoding Syntax and Semantics58
- 9.5 Basic Static Metadata Program Layer Decoding Syntax and Semantics59
- 9.6 Basic Static Metadata Content Layer Decoding Syntax and Semantics60
- 9.7 Basic Static Metadata Object Layer Decoding Syntax and Semantics62
- 9.8 Basic Static Metadata Dialogue Field Decoding Syntax and Semantics64
- 9.9 Basic Static Metadata Encapsulation Layer Decoding Syntax and Semantics64
- 9.10 Basic Static Metadata Channel Layer Decoding Syntax and Semantics67
- 9.11 Basic Static Metadata Object Interactive Field Decoding Syntax and Semantics68
- 9.12 Basic Static Metadata Speaker Location Decoding Syntax and Semantics70
- 9.13 Basic Static Metadata Loudness Field Decoding Syntax and Semantics70
- 9.14 Basic Static Metadata Program Reference Screen Field Decoding Syntax and Semantics72
- 9.15 Dynamic Metadata Level 1 Decoding Syntax and Semantics73
- 9.16 Dynamic Metadata Level 2 Decoding Syntax and Semantics75
- 9.17 Extended Static Metadata Level 1 Decoding Syntax and Semantics76
- 9.18 Extended Static Metadata Acoustic Environment Metadata Decoding Syntax and Semantics77
- 9.19 Extended Static Metadata Decoding Syntax and Semantics for Walls of the Same Material78
- 9.20 Extended static metadata. Unified geometry, material surface composition, triangle vertex decoding syntax and semantics. (80)80
- 9.21 Extended static metadata rendering information decoding syntax and semantics80
- 9.22 Extended Static Metadata Post-Processing Decoding Syntax and Semantics81
- 9.23 Extended Static Metadata Balancing Effect Decoding Syntax and Semantics82
- 9.24 Decoding process83
- Appendix A (Normative) Syntax and Semantics of Three-Dimensional Acoustic Coding Bitstream87
- A.1 Grammar87
- A.2 Semantics92
- Appendix B (Normative) Audio Code Table98
- Appendix C (Informative) 3D Sound Rendering292
- C.1 Overview292
- C.2 Metadata Limitation292
- C.3 Renderer 1292
- C.4 Renderer 2292
- C.5 Renderer 3292
- Appendix D (Informative) General Full Bitrate Audio Coding304
- D.1 Overview304
- D.2 Encoding Preprocessing309
- D.3 Lower Mix316
- D.4 Neural Network Transformation, Quantization, and Interval Encoding321
- D.5 HOA spatial code328
- D.6 Parameter Table of Encoding Neural Networks329
- Appendix E (Informative) Correspondence between the metadata in this document and the metadata in GY/T 404-2024366
- References371
Foreword
This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents". Drafting.
This document was proposed by the National Information Technology Standardization Technical Committee (SAC/TC28).
This document was prepared by the National Technical Committee on Information Technology Standardization (SAC/TC28) and the National Technical Committee on Standardization of Radio, Television and Online Audiovisual Programs.
It is under the jurisdiction of the committee (SAC/TC239).
This document was drafted by: China Electronics Technology Standardization Institute, China Media Group, and the State Administration of Radio and Television.
Planning Institute, Academy of Broadcasting Science of the State Administration of Radio and Television, Huawei Technologies Co., Ltd., Tsinghua University, Beijing Zitiao Network Technology Co., Ltd.
Company, Sainchip Microelectronics (Beijing) Technology Co., Ltd., Beijing Institute of Technology, Peking University, Migu Culture Technology Co., Ltd., China Mobile Communications China Telecom Group Corporation Limited, China United Network Communications Group Co., Ltd., China Telecom Group Corporation Limited, Tencent Technology (Shenzhen) Co., Ltd.
Huawei Terminal Technology Co., Ltd., China Mobile (Hangzhou) Information Technology Co., Ltd., China Telecom Digital Life Technology Co., Ltd., and China Unicom Online Information Technology Co., Ltd.
Technology Co., Ltd., Beijing Gehua Cable Network Co., Ltd., Oriental Cable Television Network Co., Ltd., iShang TV Media (Beijing) Co., Ltd.
Zhongguancun Audiovisual Industry Technology Innovation Alliance, World Ultra HD Video Industry Alliance.
The main drafters of this document are: Fan Kefeng, Sun Qifeng, Jiang Wenbo, Chen Chen, Ning Jinhui, Zhang Jiandong, Zhou Yun, Guo Xiaoqiang, Wang Zhe, and Dou Weibei.
Liu Derong, Wu Jian, Wang Jing, Qu Tianshu, Han Jian, Liu Xianda, Wang Yahui, Jia Liding, Li Dalong, Luo Hong, Wei Jia, Lü Chao, Zhen Lin, Dong Yuan, Wu Jian Pan Hongmei, Zhang Weimin, Zhang Wengang, Li Jingxin, Jiao Jianbo, Wang Rui, Hu Xiao, Zhu Mengyao.
Introduction
The issuing organization of this document draws your attention to the fact that declarations of compliance with this document may involve clauses 7.3, 7.4, 7.5, 7.6, 7.7, 7.9, 7.10, and 7.13.
Use of patents related to audio codec technology.
The issuing organization of this document makes no position on the authenticity, validity, or scope of the patent.
The patent holder has committed to the issuing authority of this document that he is willing to cooperate with any applicant on reasonable and non-discriminatory terms and conditions.
Next, negotiations will be held regarding patent licensing. The patent holder's statement has been filed with the issuing organization of this document, and related information can be found through the following... Contact information obtained.
Patent holder. Huawei Technologies Co., Ltd.
Address. Huawei Base A, Bantian, Longgang District, Shenzhen, Guangdong Province.
Please note that in addition to the patents mentioned above, some content in this document may still involve patents. The issuing organization of this document does not assume responsibility for identifying patents. responsibility.
Information technology 3D sound technology coding, Distribution and presentation
1 Scope
This document describes methods for encoding, distributing, and presenting three-dimensional audio and video, compatible with mono, stereo, and multi-channel surround sound. Audio format.
This document applies to broadcast television, broadcast streaming media, online audiovisual media, real-time communication, virtual reality and augmented reality, digital storage media, etc.
The field of 3D audio encoding, distribution and presentation.
2 Normative references
GB/T 17191
GB/T 33475.3-2018
GB/T 44115.3-2025
3 Terms and Definitions
The terms and definitions defined in GB/T 33475.3-2018, as well as the following terms and definitions, apply to this document.
3.1 coded bitstream
Encoded representation of audio signals.
3.2 object
In three-dimensional sound signals, a sound is perceived as a whole or as a sound source independent of its environment.
3.3 Two-channel stereo audio
An audio format that uses two channels to carry audio with a certain phase relationship, amplitude relationship, or a mixture of phase and amplitude relationships.
......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 308 pages — is available in the English PDF.
Referenced standards
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Related Standards
GB/T 33475.3-2018 — Information technology—High efficiency media coding—Part 3: Audio
GB/T 44115.3-2025 — Information technology - Virtual reality content representation - Part 3: Audio
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