Standard No.:	GB/T 46271-2025
English Name:	Information technology—3D audio technology—Coding, distribution and presentation
Chinese Name:	信息技术 三维声技术 编码、分发与呈现
Chinese Classification:	L71    Code, character set and character recognition
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR; SAC
Issued on:	2025-8-29
Implemented on:	2026-3-1
Status:	to be valid
Target Language:	English
File Format:	PDF
Word Count:	185000 words
Translation Price(USD):	5550.0
Delivery:	via email in 1~10 business day

GB/T 46271-2025 Information technology—3D audio technology—Coding, distribution and presentation English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing thorugh draft translation, self-check, revision and varification) will be delivered upon being ordered. ICS 35.040 CCS L 71 People's Republic of China National Standard GB/T 46271-2025 Information technology - 3D audio technology - Coding, distribution and presentation Issued on 2025-08-29 Implemented on 2026-03-01 Issued by State Administration for Market Regulation, Standardization Administration of China Contents 1 Scope 2 Normative References 3 Terms and Definitions 4 Abbreviations 5 Conventions 5.1 Arithmetic Operators 5.2 Logical Operators 5.3 Relational Operators 5.4 Bitwise Operators 5.5 Assignment Operators 5.6 Mnemonics 5.7 Mathematical Functions 5.8 Bitstream Syntax Rules 6 3D Audio Coding and Rendering Framework 7 Universal Full Rate Audio Decoding 8 Lossless Audio Decoding 9 Metadata Decoding 1 Scope This document describes methods for coding, distribution and presentation of 3D audio, compatible with mono, stereo, surround sound and other audio formats. This document applies to 3D audio coding, distribution and presentation in broadcasting, streaming media, network audiovisual, real-time communication, virtual/augmented reality, and digital storage media. 2 Normative References The following documents contain provisions which, through reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies; for undated references, the latest edition (including amendments) applies. GB/T 17191 (all parts) Information technology - Coding of moving pictures and associated audio for digital storage media at up to 1.5 Mbit/s GB/T 33475.3-2018 Information technology - Efficient multimedia coding - Part 3: Audio GB/T 44115.3-2025 Information technology - Virtual reality content representation - Part 3: Audio GY/T 262-2012 Program loudness and true peak audio level measurement algorithm GY/T 316-2018 Advanced sound system for program production GY/T 404-2024 Audio definition model ITU-R BS.2094:2025 Common definitions for the audio definition model ETSIT S126445 V18.1.0 Universal Mobile Telecommunications System (UMTS); LTE; 5G; Codec for Enhanced Voice Services (EVS) 3 Terms and Definitions Terms and definitions defined in GB/T 33475.3-2018 and the following apply to this document. 3.1 Coded bitstream The encoded representation of audio signals. 3.2 Object In 3D audio signals, sounds perceived as a whole or independent sounds emitted by a single sound source from the environment. 3.3 Stereo audio An audio format using two channels to carry audio signals with phase, amplitude, or mixed relationships. NOTE: Typically reproduced through two symmetrically placed speakers in front of the listener to create a wider sound field. 3.4 Surround audio An audio format using multiple channels to carry multi-channel audio signals constituting complete audio content. NOTE: Reproduced through multiple speakers surrounding the listener at ear height to create a surrounding sound field. 3.5 3D audio An audio format using multiple channels to carry multi-channel audio signals constituting complete audio content. NOTE: Reproduced directly through speakers at different height levels surrounding the listener, or after rendering to simulate 3D audio experience, providing higher spatial resolution and immersive sound fields. 4 Abbreviations The following abbreviations apply to this document. AASF: AVS Audio Storage Format AATF: AVS Audio Transport Format ADM: Audio Definition Model AVS: Audio Video coding Standard BWE: Bandwidth Extension CDF: Cumulative-probability Density Function CNN: Convolutional Neural Network CRC: Cyclic Redundancy Check DRC: Dynamic Range Control EQ: Equalizer FFT: Fast Fourier Transform FOA: First Order Ambisonics HOA: Higher Order Ambisonics ILD: Inter-channel Level Difference LFE: Low Frequence Effect LPC: Linear Prediction Coefficients LSF: Line Spectral Frequencies LSP: Line Spectral Pairs MCAC: MultiChannel Adaptive Coupling MCR: Maximum Correlation Rotation MDCT: Modified Discrete Cosine Transform M/S: Middle/Side PAR: Peak-to-Average Ratio SFB: Scale Factor Band SFM: Spectral Flatness Measure TNS: Temporal Noise Shaping VBAP: Vector-based Amplitude Panning VQ: Vector Quantization 5 Conventions 5.1 Arithmetic Operators Arithmetic operators are defined in Table 1.