Audio Signal Decoding With Temporal Mismatch Compensation

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Solution Overview

Problem

Existing audio decoding technologies face challenges in reducing the difference between output signals and original audio signals in limited communication bandwidth, particularly in scenarios with temporal shifts and phase mismatches between audio channels.

Innovation Solution

The system employs an encoder to determine temporal mismatch values between audio signals from multiple microphones, adjusts the encoding process by selecting a reference and target signal, and generates encoded mid and side signals based on these values, optimizing bit allocation to minimize bandwidth usage while maintaining audio quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If standard audio encoding is used to transmit audio signals over limited bandwidth, then bandwidth consumption is reduced, but the difference between output signals and original audio signals increases

Engineering Contradiction:
Improvebandwidth consumptionVSAvoidaudio signal accuracy
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The audio signal is segmented into mid signal and side signal components, which are then encoded separately. This segmentation allows for more efficient bandwidth utilization while preserving the essential characteristics of the original audio signal, thereby reducing the difference between output and original signals under limited bandwidth conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Temporal mismatch values and inter-channel prediction gain parameters are calculated in advance during the encoding process. These pre-computed parameters are then used to guide the decoding process, enabling the receiver to reconstruct the audio signal more accurately with fewer transmitted data elements, thus reducing bandwidth consumption without sacrificing audio quality.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If temporal mismatch compensation is implemented to reduce phase mismatches between audio channels, then audio quality is improved, but encoding complexity increases

Engineering Contradiction:
Improveaudio signal accuracyVSAvoidencoding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The encoder dynamically adjusts encoding parameters based on calculated temporal mismatch values and inter-channel prediction gain. By changing parameters such as bit allocation and prediction strength according to the measured temporal characteristics, the system achieves improved audio quality without requiring complex real-time processing, thus managing encoding complexity effectively.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If dynamic bit allocation is used to optimize bandwidth usage, then network resource efficiency is improved, but decoding complexity increases

Engineering Contradiction:
Improvenetwork resource efficiencyVSAvoiddecoding process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The encoding process incorporates feedback mechanisms where temporal mismatch values and inter-channel prediction gain parameters are calculated and used to dynamically adjust bit allocation. These feedback-driven parameter adjustments enable efficient bandwidth usage while the pre-computed nature of the parameters keeps the decoding complexity manageable, as the decoder simply needs to apply the received parameters rather than perform complex real-time calculations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3692526B1Decoding of audio signals
Publication Date: 2023.12.06 QUALCOMM INC
  • EP3692526B1 patent drawingFigure 1
  • EP3692526B1 patent drawingFigure 2
  • EP3692526B1 patent drawingFigure 3

AI summary

A device includes a receiver and a decoder. The receiver is configured to receive bitstream parameters corresponding to at least an encoded mid signal. The decoder is configured to generate a synthesized mid signal based on the bitstream parameters. The decoder is also configured to generate a synthesized side signal selectively based on the bitstream parameters in response to determining whether the bitstream parameters correspond to an encoded side signal.