Audio Decoder Using Matching Pursuit and HOA
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Solution Overview
Problem
Current audio technologies face challenges in delivering immersive audio content efficiently over limited bandwidth while maintaining high quality, as traditional formats like two-channel stereo require larger bandwidth for immersive experiences such as multi-channel and ambisonics.
Innovation Solution
The implementation of a Matching Pursuit (MP) coding-based algorithm for encoding and decoding audio content, which converts input audio signals into higher-order ambisonics (HOA) representations, allowing for bitrate reduction by transmitting encoded HOA data alongside metadata to reconstruct immersive audio signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional audio formats (two-channel stereo, multi-channel) are used to deliver immersive audio content, then audio quality and immersion experience are maintained, but bandwidth requirements increase
Solution Approach 1:
The patent transforms the audio signal from traditional channel-based representation to Higher-Order Ambisonics (HOA) spherical harmonic coefficients representation. This parameter transformation allows the audio content to be encoded more efficiently, reducing the bandwidth required while maintaining immersive audio quality. The HOA coefficients capture the spatial audio information in a compressed form that requires fewer bits for transmission compared to traditional multi-channel formats.
2Quantity of substance
If higher-order ambisonics (HOA) representation is used to reduce bandwidth, then bandwidth requirements are reduced, but encoding and decoding complexity increases
Solution Approach 1:
The patent pre-calculates and stores conversion matrices for transforming between different HOA orders and for decoding to various output channel configurations. By preparing these transformation matrices in advance, the system avoids performing complex real-time matrix calculations during encoding and decoding operations, thereby reducing computational complexity while maintaining the bandwidth reduction benefits of HOA representation.
3Quantity of substance
If higher-order ambisonics (HOA) representation is used to reduce bandwidth, then bandwidth requirements are reduced, but decoding and rendering complexity increases
Solution Approach 1:
The patent pre-calculates and stores conversion matrices for transforming between different HOA orders and for decoding to various output channel configurations. By preparing these transformation matrices in advance, the system avoids performing complex real-time matrix calculations during encoding and decoding operations, thereby reducing computational complexity while maintaining the bandwidth reduction benefits of HOA representation.
Solution Approach 2:
The patent implements adaptive decoding that dynamically adjusts the decoding process based on the capabilities of the playback system. The decoder can adaptively select the appropriate output channel configuration and transformation matrices based on the number and arrangement of available speakers, allowing the system to optimize rendering complexity for different playback environments while maintaining efficient bandwidth usage.
Data Source
AI summary
A method that includes a decoder-side method that includes receiving a bitstream that includes an encoded representation of an input audio signal and metadata associated with the input audio signal, producing a decoded representation of the input audio signal by decoding the encoded representation using a Matching Pursuit (MP) coding-based algorithm, producing audio driver signals by rendering the input audio signal based on the metadata, and driving speakers using the audio driver signals.