Encoding Rate Controller for Audio Signal Bandwidth Control

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Solution Overview

Problem

Existing electronic devices face challenges in controlling the average encoding rate of audio signals, leading to undesirable bandwidth occupation and potential speech artifacts due to variable rate encoding systems, which fail to maintain a consistent desired capacity and quality.

Innovation Solution

The implementation of an encoding rate controller that determines and adjusts thresholds based on metrics such as SNR and frame types, dynamically selecting encoders to encode frames at optimal rates, ensuring a target average encoding rate is maintained while minimizing speech artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variable rate encoding systems are used to adapt to different speech properties, then encoding flexibility is improved, but average encoding rate control deteriorates leading to excessive bandwidth occupation

Engineering Contradiction:
Improveencoding flexibilityVSAvoidbandwidth usage
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent implements a feedback mechanism where the encoder monitors the average encoding rate over multiple frames and adjusts the encoding rate of subsequent frames accordingly. When the average rate exceeds the target rate, the encoder reduces the rate of following frames to bring the average back down, creating a closed-loop control system that maintains rate compliance while preserving encoding flexibility.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the encoding rate of individual frames based on real-time conditions and the current average rate status. Rather than using a fixed encoding rate, the system varies the rate frame-by-frame while maintaining overall control, allowing adaptation to speech properties while preventing excessive bandwidth consumption through active rate management.

Inventive Principle:
Principle #15Dynamics

2Reliability

If higher encoding rates are used to improve speech quality, then speech quality is improved, but bandwidth occupation increases

Engineering Contradiction:
Improvespeech qualityVSAvoidbandwidth usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the encoding rate parameter dynamically based on speech characteristics and bandwidth conditions. By analyzing speech properties such as voicing detection and spectral features, the encoder adjusts the bit rate parameter to match the actual speech content requirements, using higher rates only when necessary for quality and lower rates when speech content permits, thus optimizing the quality-bandwidth tradeoff.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If encoding rate is reduced to save bandwidth, then bandwidth usage is reduced, but speech artifacts increase

Engineering Contradiction:
Improvebandwidth usageVSAvoidspeech artifacts
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by differentiating encoding treatment for different speech segments. Rather than uniformly reducing the encoding rate across all frames, the system identifies specific frames or speech regions where quality is critical and maintains higher encoding rates for those portions while allowing lower rates for less critical segments, thus reducing overall bandwidth usage without introducing artifacts in important speech regions.

Inventive Principle:
Principle #3Local quality

4Quantity of substance

If average encoding rate is strictly controlled to meet target rate, then bandwidth compliance is improved, but encoding adaptability deteriorates

Engineering Contradiction:
Improveencoding rateVSAvoidencoding adaptability
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary analysis of speech frames to predict appropriate encoding rates before actual encoding. By pre-classifying frames according to their speech characteristics and anticipating bandwidth requirements, the encoder can make informed rate decisions that balance target rate compliance with speech quality preservation, avoiding both excessive rate control that would harm adaptability and insufficient control that would exceed bandwidth limits.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2959484B1Systems and methods for controlling an average encoding rate
Publication Date: 2019.08.28 QUALCOMM INC
  • EP2959484B1 patent drawingFigure 1
  • EP2959484B1 patent drawingFigure 2
  • EP2959484B1 patent drawingFigure 3

AI summary

A method for controlling an average encoding rate by an electronic device is described. The method includes obtaining a speech signal. The method also includes determining a first average rate. The method further includes determining a first threshold based on the first average rate. The method additionally includes controlling the average encoding rate by determining at least one other threshold based on the first threshold. The method also includes sending an encoded speech signal.