7/31/2019 Large-Scale Works on Algorithms of Quality of Experience (QoE)

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Konferencja Uytkownikw Komputerw Duej Mocy7-9 Marca 2012, Zakopane

Academic Computer Centre CYFRONET

Mikoaj Leszczuk, Piotr Romaniak, Andrzej Gowacz, JanDerkacz, Andrzej Dziech

Large-Scale Works on Algorithms of Qualityof Experience (QoE)

Introduction to QoE Measurement Subjective experiments is itnecessary?

Full-Reference Video Quality Metrics

The experiment

Time consuming

Resources consumingOne hundred testers

Methodology: ITU'sACR-HR (AbsoluteCategory Rating withHidden Reference,ITU-T P.910)

No-Reference scenario

Full-Reference scenario

PSNR is it good enough? SSIM Structural Similarity

Large volume and variety of multimedia

content

Efficient compression algorithms

required to minimize data volume

Quality of Experience aware compression

is desired

Maximizing QoE

Minimizing data volume

Proposed Solution Task: develop a metric for H.264 video compression quality

assessment

Full-reference scenario

Quality assessment

Content aware compression parameters adjustment

Cooperation within the SYNAT Project

Video Quality Experts Group (VQEG)

Joint Efforts Group (JEG), Hybrid project

H.264 encoding compression quality assessment

Experiment Scale Selection of Source Video Sequences (SRC): around 100

10 seconds long

30 FPS

Resolution from SD (640x480) to HD (1920x1080)

Selection of Hypothetical Reference Circuits (HRC): 1600

Summary: 100x10x30x1600 = 48 000 000 video frames:

Each video frame has to encoded (e.g. 1s required to encode a single

video frame with JM Reference Software using one CPU core)

Calculation of video quality metrics for each video frame

Calculation of video content characteristics for each video frame

Calculation time using single core = 2222 days Assumption 1: 48 000 000 video frames Assumption 2: compression of one video frame in 1s Assumption 3: three video quality metrics to be calculated for

all video frames Assumption 4: calculation of one video quality metric for one

frame in 1s

Compression parameters Constant bitrate of at least 5 levels

Constant quantization factor

of at least 5 levels Group of Pictures (GoP) structure different sizes and structures:

Of at least 2 levels with a variable number of I frames per second

Of at least 2 levels with a variable number of B and P frames per second

Hierarchical coding of at least 2 horizontal variants

Structure of slices of at least 2 levels

Number of frames per second of at least 2 levels (original and halved)

Resolution of at least 2 levels (original and halved)