Subjective evaluation of UHD video coded using VVC with LCEVC and ML-VVC

TL;DR

This study evaluates the subjective visual quality of UHD videos encoded with VVC combined with LCEVC and ML-VVC, comparing enhancement layers and reference methods through viewer ratings.

Contribution

It provides a comprehensive subjective assessment of multilayer UHD video coding with LCEVC on top of VVC, using standardized testing and a diverse set of sequences.

Findings

LCEVC enhancement layer improves perceived quality at low bitrates.

Subjective scores favor multilayer VVC over simple upsampling.

Different operating points show trade-offs between bitrate and quality.

Abstract

This paper presents the results of a subjective quality assessment of a multilayer video coding configuration in which Low Complexity Enhancement Video Coding (LCEVC) is applied as an enhancement layer on top of a Versatile Video Coding (VVC) base layer. The evaluation follows the same test methodology and conditions previously defined for MPEG multilayer video coding assessments, with the LCEVC enhancement layer encoded using version 8.1 of the LCEVC Test Model (LTM). The test compares reconstructed UHD output generated from an HD VVC base layer with LCEVC enhancement against two reference cases: upsampled VVC base layer decoding and multilayer VVC (ML-VVC). Two operating points are considered, corresponding to enhancement layers representing approximately 10% and 50% of the total bitrate. Subjective assessment was conducted using the Degradation Category Rating (DCR) methodology with twenty five participants, across a dataset comprising fifteen SDR and HDR sequences. The reported results include Mean Opinion Scores (MOS) with associated 95% confidence intervals, enabling comparison of perceptual quality across coding approaches and operating points within the defined test scope.