3D Down-Mix Signal Decoding for Headphone Audio Rendering
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Solution Overview
Problem
Existing audio signal processing technologies fail to efficiently reproduce multi-channel signals with 3D effects across various reproduction environments, particularly when using fewer than three speakers, such as headphones, which limits the immersive audio experience.
Innovation Solution
The proposed method involves a decoding process that extracts and compensates down-mix signals using compensation information, followed by a 3D rendering operation to generate a 3D down-mix signal, utilizing filter information and head-related transfer functions to simulate multi-channel audio from fewer speakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multi-channel signals are reproduced using 2-channel speakers such as headphones, then the number of speakers is reduced, but the ability to create three-dimensional (3D) sound effects deteriorates
Solution Approach 1:
The patent applies parameter changes by transforming the audio signal parameters through 3D rendering operations. The decoding apparatus processes the down-mixed signal by applying spatial parameters and 3D rendering techniques to create virtual multi-channel sound fields from 2-channel inputs, thereby maintaining 3D sound effects capability while using fewer speakers
Solution Approach 2:
The patent introduces 3D rendering operations and compensation information as intermediary processing steps between the down-mixed signal and the final output. These intermediary operations synthesize virtual multi-channel signals that simulate 3D spatial effects, enabling 2-channel speakers to reproduce immersive audio experiences
2Productivity
If down-mixing is performed to reduce channel count, then transmission efficiency is improved, but the quality of reproduced multi-channel signal deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and embedding compensation information during the encoding phase. This compensation data is stored in the bitstream and later used by the decoding apparatus to restore and compensate the down-mixed signal, thereby maintaining high reproduction quality while benefiting from efficient down-mixing transmission
Solution Approach 2:
The patent implements feedback mechanisms where compensation information derived from the original multi-channel signal is fed back into the decoding process. This feedback loop allows the decoding apparatus to adjust and refine the reconstructed signal, improving reproduction quality without compromising transmission efficiency
Data Source
AI summary
An encoding method and apparatus and a decoding method and apparatus are provided. The decoding method includes extracting an arbitrary down-mix signal and compensation information necessary for compensating for the arbitrary down-mix signal from the input bitstream, compensating for the arbitrary down-mix signal using the compensation information, and generating a three-dimensional (3D) down-mix signal by performing a 3D rendering operation on the compensated arbitrary down-mix signal. Accordingly, it is possible to efficiently encode multi-channel signals with 3D effects and to adaptively restore and reproduce audio signals with optimum sound quality according to the characteristics of an audio reproduction environment.