Entropy-Coded Audio Stream Packing With Error-Resilient Touchup Bits

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Solution Overview

Problem

Existing methods for packing variable-length entropy-coded data into a fixed-rate stream are inefficient, prone to error propagation, and incur wastage due to the need for variable data rates and sensitivity to bit errors, particularly in applications where delay is critical and natural block structures are absent.

Innovation Solution

The method involves dividing signal data into coarse and touchup codewords, where coarse codewords are derived from the most significant bits and touchup codewords from the least significant bits, with predetermined touchup bit positions allowing flexible placement and error resilience, enabling efficient packing and decoding without requiring fixed block sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If variable-length entropy coded data is packed contiguously into a fixed-rate stream, then coding efficiency is improved, but error propagation increases

Engineering Contradiction:

Improvecoding efficiencyVSAvoiderror propagation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the data stream by inserting synchronization markers at predetermined intervals, dividing the continuous variable-length coded data into discrete segments. This allows the decoder to resynchronize after bit errors without propagating errors indefinitely, while maintaining the efficiency benefits of variable-length coding.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces synchronization markers as intermediary elements between the variable-length codewords. These markers act as delimiters that help the decoder identify codeword boundaries and resynchronize after errors, without significantly increasing the overall data rate.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If contiguous packing of variable-length codewords is used, then data rate efficiency is improved, but sensitivity to bit errors increases

Engineering Contradiction:

Improvedata rate efficiencyVSAvoidsensitivity to bit errors

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary actions by pre-calculating and inserting synchronization markers at predetermined positions in the data stream before transmission. This allows the decoder to be prepared for potential resynchronization points, reducing the impact of bit errors without sacrificing data rate efficiency.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If fixed block sizes are used for error resilience, then error propagation is limited, but data wastage increases

Engineering Contradiction:

Improveerror resilienceVSAvoiddata wastage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent introduces dynamic resynchronization points through synchronization markers, allowing the effective block size to adapt to the actual data content. This maintains error resilience by limiting error propagation to segments between markers, while avoiding the fixed block size wastage by allowing variable-length codewords to fill segments efficiently.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP2347512B1Improved lossy coding of signals

Publication Date: 2019.08.14 CRAVEN PETER G

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AI summary

A method is described for packing variable-length entropy coded data into a fixed rate data stream along with resolution enhancement data, the method providing tightly constrained propagation of transmission channel errors and graceful degradation of signal resolution as entropy-coded data rate increases. An application to a multiband ADPCM audio codec is also described.