Ambisonic Coefficient Transition Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current audio compression technologies face challenges in efficiently encoding and decoding higher-order ambisonic audio data, particularly in handling multiple transitions within a frame, which can result in redundant information and energy amplification during reconstruction.
Innovation Solution
The proposed solution involves a bitstream signaling mechanism that tracks ambient HOA coefficient transitions and adjusts the encoding of foreground and background channels, removing redundant information by specifying only necessary vector elements, thereby improving coding efficiency and soundfield reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple transitions are handled by encoding all vector elements for each transition, then transition accuracy is improved, but data redundancy increases and coding efficiency deteriorates
Solution Approach 1:
The patent extracts only the necessary vector elements that change during transitions, rather than encoding all vector elements. By identifying and encoding only the specific elements that undergo transition (e.g., when ambient HOA coefficients change from foreground to background or vice versa), the system maintains transition accuracy while eliminating redundant data encoding.
Solution Approach 2:
The patent applies different encoding strategies to different parts of the data structure based on their transition characteristics. Vector elements are categorized by their transition behavior, and only those requiring updates are encoded with full precision, while stable elements are handled differently or omitted, creating a localized optimization approach.
2Loss of information
If all vector elements are encoded during transitions, then information completeness is improved, but energy amplification occurs during reconstruction
Solution Approach 1:
The patent removes redundant vector element encodings that would otherwise be included during transitions. By extracting only the essential changing elements and excluding redundant repetitions, the system preserves necessary information for accurate reconstruction while preventing the accumulation of redundant energy that would cause amplification artifacts.
3Measurement precision
If redundant information is retained in the bitstream, then reconstruction accuracy is improved, but bitstream size increases and transmission efficiency deteriorates
Solution Approach 1:
The patent extracts and retains only the essential vector elements required for accurate soundfield reconstruction, removing redundant information from the bitstream. By carefully selecting which vector elements to encode based on their actual contribution to reconstruction accuracy, the system minimizes bitstream size while preserving sufficient information for faithful soundfield reproduction.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In general, techniques are described for coding higher-order ambisonic coefficients during multiple transitions. A device comprising a processor and a memory coupled to the processor may be configured to perform the techniques. The processor may be configured to obtain a multi-transition indication of whether an ambient HOA coefficient is in transition during a same frame of the bitstream as a foreground audio signal is in transition. The processor may also be configured to obtain a vector that describes a spatial characteristic of a corresponding foreground audio signal based on the multi-transition indication, both the vector and the corresponding HOA audio signal decomposed from the HOA audio data. The memory may be configured to store the vector.