Multi-Channel Audio Encoding with Stable Frame Parameters
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Solution Overview
Problem
Existing multi-channel parameter calculation methods in stereo encoding, such as PS encoding, are unstable due to factors like background noise and reverberation, leading to discontinuous downmixed signals and poor audio quality.
Innovation Solution
A method and encoder that determine a multi-channel parameter for the current frame by considering both the characteristic parameters of the current frame and the difference between the current frame and previous frames, ensuring accurate inter-channel information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-channel parameters are calculated using existing PS encoding schemes, then encoding compression is achieved, but parameter stability deteriorates due to background noise and reverberation
Solution Approach 1:
The patent applies dynamics by making the multi-channel parameter determination adaptive rather than static. The encoder dynamically adjusts whether to use current frame parameters or previous frame parameters based on real-time stability assessment. This is achieved through a parameter stability judgment module that continuously evaluates whether parameters meet preset stability criteria, allowing the system to flexibly switch between different parameter sources to maintain both compression and stability.
Solution Approach 2:
The patent implements feedback by using the stability assessment result to control parameter selection. The parameter stability judgment module evaluates the stability of multi-channel parameters and feeds this information back to the parameter determination process. When parameters are determined to be unstable, the system feedbacks to use previous stable parameters instead, creating a closed-loop control mechanism that maintains parameter reliability while preserving encoding efficiency.
2Measurement precision
If multi-channel parameters are frequently adjusted to adapt to changing audio conditions, then encoding accuracy improves, but parameter discontinuity increases causing acoustic image jitter
Solution Approach 1:
The patent applies preliminary anti-action by proactively preventing parameter discontinuity before it occurs. The system uses a parameter stability judgment module to predict when parameters might become unstable and takes preventive action by switching to previous stable parameters. This anticipatory approach counteracts potential parameter jumps and acoustic image jitter before they can manifest, maintaining both accuracy and continuity.
Solution Approach 2:
The patent implements parameter changes by selectively switching between different parameter sources (current frame parameters vs. previous frame parameters) based on stability conditions. When current parameters fail stability criteria, the system changes to using previous stable parameters, creating a conditional parameter selection mechanism that maintains continuity while allowing necessary adaptations for accuracy.
3Adaptability or versatility
If downmixed signals are calculated based on unstable multi-channel parameters, then encoding flexibility is maintained, but audio quality deteriorates due to signal discontinuity
Solution Approach 1:
The patent introduces an intermediary component - the parameter stability judgment module - that mediates between encoding flexibility and signal continuity. This intermediary assesses parameter stability and controls the selection of multi-channel parameters used for downmixed signal calculation, acting as a buffer that prevents unstable parameters from causing signal discontinuity while maintaining encoding adaptability.
Solution Approach 2:
The patent applies beforehand cushioning by preparing stable parameters from previous frames in advance to cushion against potential instability in current frame parameters. This pre-prepared stable parameter buffer protects the downmixed signal from discontinuity when current parameters are unstable, maintaining audio quality while preserving encoding flexibility through selective parameter usage.
Data Source
AI summary
A multi-channel signal encoding method includes obtaining a multi-channel signal of a current frame; determining an initial multi-channel parameter of the current frame; determining a difference parameter based on the initial multi-channel parameter of the current frame and multi-channel parameters of previous K frames of the current frame, where the difference parameter represents a difference between the initial multi-channel parameter of the current frame and the multi-channel parameters of the previous K frames, and K is an integer greater than or equal to one; determining a multi-channel parameter of the current frame based on the difference parameter and a characteristic parameter of the current frame; and encoding the multi-channel signal based on the multi-channel parameter of the current frame.