Spherical Harmonic Audio Encoding Parameter Reuse
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current audio encoding technologies lack flexibility and efficiency in representing and transmitting higher-order ambisonic audio data, which is independent of speaker geometry, leading to inefficiencies in storage and playback across different speaker configurations.
Innovation Solution
The use of spherical harmonic coefficients (SHC) to represent soundfields, combined with vector-based and directional-based synthesis methods for encoding and decoding, allows for efficient transmission and playback of higher-order ambisonic audio data, adapting to various speaker geometries and acoustic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If higher-order ambisonic audio data is encoded using traditional audio encoding technologies, then the encoding process is simple, but the flexibility and efficiency in representing soundfields independent of speaker geometry is poor
Solution Approach 1:
The patent transforms the audio encoding approach by changing the parameter representation from traditional channel-based encoding to spherical harmonic coefficients. This parameter transformation enables the soundfield to be represented independently of speaker geometry, achieving geometric invariance while maintaining encoding efficiency through mathematical transformation.
Solution Approach 2:
The patent introduces a new dimensional framework by representing audio data in spherical harmonic space rather than traditional Cartesian coordinate systems. This dimensional transformation allows the soundfield to be decoded for any speaker geometry, providing adaptability across different playback configurations without re-encoding.
2Adaptability or versatility
If spherical harmonic coefficients are used to represent soundfields, then compatibility across different speaker configurations is improved, but storage and transmission requirements increase
Solution Approach 1:
The patent segments the spherical harmonic coefficient data into different order components, allowing selective encoding and transmission of only the necessary coefficients. By dividing the complete spherical harmonic expansion into manageable segments, the storage and transmission requirements are reduced while maintaining compatibility across speaker configurations.
Solution Approach 2:
The patent extracts and transmits only the essential spherical harmonic coefficients required for accurate soundfield reproduction, rather than encoding complete high-resolution data. This extraction approach reduces storage requirements while preserving the geometric invariance property across different speaker setups.
3Productivity
If vector quantization with Huffman tables is used for coding vectors, then compression efficiency is improved, but the ability to preserve spatial information accuracy deteriorates
Solution Approach 1:
The patent performs preliminary organization and normalization of spherical harmonic coefficients before quantization, arranging them in an optimal sequence that maximizes compression efficiency. This preliminary action ensures that the most significant spatial information is preserved while achieving high compression ratios through subsequent Huffman coding.
Solution Approach 2:
The patent applies adaptive quantization parameters that change based on the significance of different spherical harmonic coefficients. By dynamically adjusting the precision of coefficient representation, the system maintains spatial information accuracy for critical coefficients while achieving compression for less significant ones, resolving the trade-off between accuracy and efficiency.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In general, techniques are described for indicating frame parameter reusability for decoding vectors. A device comprising a processor and a memory may perform the techniques. The processor may be configured to obtain a bitstream comprising a vector representative of an orthogonal spatial axis in a spherical harmonics domain. The bitstream may further comprise an indicator for whether to reuse, from a previous frame, at least one syntax element indicative of information used when compressing the vector. The memory may be configured to store the bitstream.