Interchannel Phase Difference Encoding with Temporal Mismatch Analysis
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Solution Overview
Problem
Existing audio encoding technologies face challenges in efficiently encoding interchannel phase differences between audio signals, particularly due to limited bits available for encoding and the complexity of identifying which encoding parameters have the greatest impact on audio quality, leading to suboptimal audio quality when encoding multiple audio signals with temporal misalignment.
Innovation Solution
A device and method that include an interchannel temporal mismatch analyzer, an IPD mode selector, and an IPD estimator to determine and adjust the resolution of interchannel phase difference (IPD) values based on the temporal misalignment and characteristics of the audio signals, optimizing bit allocation for better audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more bits are allocated to encoding parameters with greater impact on audio quality, then audio quality is improved, but identifying which parameters have the greatest impact is complex
Solution Approach 1:
The patent changes the resolution parameter of IPD values dynamically based on temporal misalignment characteristics. By adjusting the resolution (number of bits) according to the actual audio signal properties and temporal mismatch degree, the system allocates encoding bits adaptively to parameters that truly impact audio quality, avoiding the complexity of manual parameter identification while maintaining high audio quality where needed.
Solution Approach 2:
The patent implements dynamic selection of IPD resolution modes based on real-time analysis of temporal misalignment. The encoder switches between different resolution levels (e.g., 0.5-bit, 1-bit, 2-bit per frequency bin) depending on the measured temporal mismatch, making the encoding process adaptive rather than static. This dynamic approach automatically prioritizes parameters with greater impact on quality without requiring complex pre-identification of all such parameters.
2Measurement precision
If IPD values are encoded with high resolution, then audio quality is improved, but the number of bits required increases
Solution Approach 1:
The patent changes the resolution parameter of IPD values dynamically based on temporal misalignment characteristics. By adjusting the resolution (number of bits) according to the actual audio signal properties and temporal mismatch degree, the system allocates encoding bits adaptively to parameters that truly impact audio quality, avoiding the complexity of manual parameter identification while maintaining high audio quality where needed.
Solution Approach 2:
The patent applies partial high-resolution encoding only where necessary. Instead of encoding all IPD values at maximum resolution, the system applies high resolution (e.g., 2 bits per bin) only to frequency bins or time frames where temporal misalignment is significant, and uses lower resolution elsewhere. This partial application of high-resolution encoding maintains audio quality where needed while reducing overall bit rate.
3Device complexity
If audio signals with temporal misalignment are encoded without adjustment, then encoding complexity is reduced, but audio quality deteriorates
Solution Approach 1:
The patent performs preliminary analysis of temporal misalignment between audio channels before the main encoding process. The encoder first measures the inter-channel temporal mismatch and determines appropriate alignment corrections or resolution adjustments in advance. This preliminary action prepares the encoding parameters optimally for the specific signal characteristics, ensuring high audio quality without adding significant complexity during the main encoding operation.
Solution Approach 2:
The patent introduces an intermediate analysis step that measures temporal misalignment and uses this information to mediate the encoding process. This intermediary measurement acts as a bridge between the raw audio signals and the encoding parameters, automatically determining the appropriate IPD resolution and alignment adjustments needed. This intermediary step simplifies the overall process by automating the adaptation rather than requiring complex manual intervention.
Data Source
AI summary
A device for processing audio signals includes an interchannel phase difference (IPD) mode selector and an IPD estimator. The IPD mode selector is configured to select an IPD mode from among at least a first IPD mode and a second IPD mode based on at least an interchannel temporal mismatch value indicative of a temporal misalignment between a first audio signal and a second audio signal. The IPD estimator is configured to determine IPD values based on the first audio signal and the second audio signal, the IPD values represented using a first number of bits responsive to selection of the first IPD mode or represented using a second number of bits responsive to selection of the second IPD mode.