Interchangeable CELP and VQ-Based NFC Audio Encoders

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Solution Overview

Problem

Current speech and audio coding systems are limited by the inability to interoperate between Code Excited Linear Prediction (CELP) and Vector Quantization (VQ) based noise feedback coding technologies, requiring transcoders to convert between different coding methods.

Innovation Solution

Designing CELP encoders to be compatible with VQ-based decoders and vice versa, allowing for interoperability between CELP and VQ-based noise feedback coding systems, using shared decoder structures and functional blocks for excitation signal encoding and quantization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CELP and TSNFC systems use different encoding methods, then each system can be optimized for its specific coding technique, but interoperability between the two systems is lost

Engineering Contradiction:
Improvesystem optimizationVSAvoidinteroperability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal decoder structure that can decode both CELP-encoded and TSNFC-encoded bitstreams. The decoder is designed with functional blocks that can process excitation signals from either encoding method, allowing a single decoder to serve multiple encoding standards without requiring separate dedicated decoders for each system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a transcoder as an intermediary component that converts between CELP and TSNFC encoding formats. This transcoder acts as a mediator that enables communication between the two different coding systems by transforming one format into the other, allowing interoperability while preserving the optimizations of each specific encoding method.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a transcoder is introduced to convert between CELP and TSNFC formats, then interoperability is achieved, but system complexity increases

Engineering Contradiction:
ImproveinteroperabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the transcoder functionality with the existing CELP and TSNFC encoders/decoders. Rather than adding completely separate transcoder components, the conversion functionality is integrated into the existing system architecture, sharing common functional blocks such as excitation signal processing and synthesis filters, thereby reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The decoder is designed with multi-functionality to handle both CELP and TSNFC formats natively, eliminating the need for separate transcoders in many scenarios. By making the decoder universal, the system reduces complexity compared to having dedicated decoders plus separate transcoder components for each format conversion.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1879178B1Interchangeable noise feedback coding and code excited linear prediction encoders
Publication Date: 2013.11.06 BROADCOM INC
  • EP1879178B1 patent drawingFigure 1~2
  • EP1879178B1 patent drawingFigure 3~4
  • EP1879178B1 patent drawingFigure 5

AI summary

A system and method for encoding and decoding speech signals that includes a specially-designed Code Excited Linear Prediction (CELP) encoder and a vector quantization (VQ) based Noise Feedback Coding (NFC) decoder or that includes a specially-designed VQ-based NFC encoder and a CELP decoder. The VQ based NFC decoder may be a VQ based two-stage NFC (TSNFC) decoder. The specially-designed VQ-based NFC encoder may be a specially-designed VQ based TSNFC encoder. In each system, the encoder receives an input speech signal and encodes it to generate an encoded bit stream. The decoder receives the encoded bit stream and decodes it to generate an output speech signal. A system and method is also described in which a single decoder receives and decodes both CELP-encoded audio signals as well as VQ-based NFC-encoded audio signals.