Layer-Aware FEC Interleaving for Burst-Resilient SVC Video
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Solution Overview
Problem
Existing error correction techniques for Scalable Video Coding (SVC) fail to effectively protect the base layer while ensuring robustness, leading to loss of enhancement layer data when the base layer is missing, resulting in reduced video quality and service continuity.
Innovation Solution
The Layer-Aware Forward Error Correction (LA-FEC) approach extends the encoding process across dependent video layers, using Raptor codes and LDPC codes to generate redundancy, ensuring the base layer can be decoded independently while providing additional error correction for more important layers without additional repair data, and integrating unequal interleaving to enhance time diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard FEC is used for SVC with equal interleaving length, then implementation is simple, but base layer cannot be effectively protected against burst errors
Solution Approach 1:
The patent segments the interleaving process into two distinct parts: a first interleaver with shorter length for base layer data and a second interleaver with longer length for enhancement layer data. This segmentation allows each layer to be protected according to its specific requirements, with the base layer receiving faster protection and the enhancement layer receiving stronger protection against burst errors, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent applies local quality by providing different interleaving lengths tailored to different layers. The base layer uses a shorter interleaving length appropriate for its urgency and importance, while the enhancement layer uses a longer interleaving length for superior burst error protection. This localized optimization resolves the contradiction by making each part of the system have the quality it specifically needs.
2Reliability
If longer interleaving length is used for enhancement layer, then burst error protection is improved, but service continuity is reduced when base layer is missing
Solution Approach 1:
The patent segments the error protection mechanism into layer-specific interleavers, allowing the base layer to be processed independently with shorter interleaving for faster service continuity, while the enhancement layer simultaneously receives longer interleaving for superior burst error protection. This segmentation ensures that base layer availability is not compromised by enhancement layer processing.
Solution Approach 2:
The patent implements preliminary action by ensuring the base layer is decoded and made available first through the shorter first interleaver, before the enhancement layer processing completes. This preliminary availability of the base layer maintains service continuity, while the longer second interleaver subsequently provides enhanced protection for the enhancement layer data.
3Adaptability or versatility
If separate FEC is used for each layer, then layer independence is maintained, but overall error correction capability is reduced
Solution Approach 1:
The patent merges the FEC processing into a unified structure where a single FEC encoder generates parity bits for both base layer and enhancement layer data together. The first interleaver processes base layer data and the second interleaver processes enhancement layer data, but both share the same FEC code structure and parity generation mechanism. This merging maintains layer independence through separate interleaving while achieving superior overall error correction capability through combined FEC processing.
Data Source
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AI summary
An error correcting encoder comprises an error correcting data generator for receiving payload data belonging to a first category (first category payload data), for receiving payload data belonging to a second category, for determining first error correcting data for the first category payload data, and for determining second error correcting data for the second category payload data. The error correcting encoder further comprises an interleaver for interleaving at least the second error correcting data and the second category payload data with each other. A first interleaving length relative to an interleaving of the first error correcting data and the first category payload data is different from a second interleaving length relative to the interleaving of the second error correcting data and the second category payload data. A corresponding error correcting decoder and methods for error correcting encoding/decoding are also disclosed. According to alternative embodiments, a payload interleaving length is different from an error correcting data interleaving length.