Wyniki wyszukiwania - BazTech

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Subjective quality evaluation of 8- and 10-bit MP4-coded video sequences from Netflix

Falkowski-Gilski Przemysław, Uhl Tadeus, Divakarachari Parameshachari Bidere

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2024

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nr 79 (151)

30--38

EN

Recently, many researchers have been intensively conducting quality of service (QoS), quality of experience (QoE), and user experience (UX) studies in the field of video analysis. This paper is intended to make a new, complementary contribution to this field. Currently, streaming platforms are key products in relation to delivering video content online. Most often, they include the MP4 video format, which is most widely utilized among audio-visual codecs. This study involves a group of 38 individuals, aged between 21–35 years old, in a laboratory consisting of 20 iMacs with 4K retina display. The presented signal sequences included content sourced from the Netflix Chimera repository, with 8- and 10-bit depth, available in different resolutions of 270p, 432p, 720p, and 1080p. Tests included a subjective quality evaluation in a 5-step mean opinion score (MOS) scale, focused on the UX aspect. According to the obtained results, content with the lowest and highest resolutions is optimal in 8-bit depth, while movies with intermediate resolutions are better in 10-bit depth. For 8-bit content, the main problem is pixelation, whereas, in the case of 10-bit samples, the main issue is color noise, particularly in the case of the lowest resolution. Many viewers indicated that 10-bit encoding offered lower quality. Moreover, 8-bit movies caused a lower quality of the gradient, presumably due to the smaller range of the available color. However, 8-bit movies in the same situation generate visible stripes on static images in the background, causing a lower quality of the gradient, which is probably due to the smaller range of available colors. The results of the performed experiments may be of particular interest to content creators and distributors, particularly network and cable operators, as well as wireless and wired providers. coding, compression, QoE (Quality of Experience), UX (User Experience), video content, Netflix.

2

Cellular network quality evaluation at a university campus on the eve of 5G

Falkowski-Gilski Przemysław, Uhl Tadeus

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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nr 70 (142)

73--80

EN

Thanks to the availability of mobile devices and the spread of broadband access around the world, the number of network users continues to grow. This has raised user awareness when it comes to the quality of content they consume. Many service providers and operators focus on monitoring QoN (Quality of Network) and QoS (Quality of Service) parameters, particularly those influenced by bandwidth and latency. However, for most end-users, quality is understood as the subjective QoE (Quality of Experience), a mixture of several individual factors. This paper presents a QoN evaluation, carried out under real-time operating conditions at a university campus, considering the overall performance of the cellular network. The study involved 50 mobile devices, i.e., smartphones, used by students during their typical activity throughout a week. The results were gathered on the eve of 5G, using a custom-built Android application. This application enabled the acquisition of valuable data about the wireless link, including download and upload speed, latency (pink), the ID of the serving base station, and type of cellular connection. This approach can be used to detect the strengths and weaknesses of back-end networks.

3

Jakość obrazu dla zastosowań użytkowych: definicje, badania, standaryzacja i aktualne trendy

Leszczuk M.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2010

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nr 6

242-246

PL

Monitoring bezpieczeństwa publicznego (ruch uliczny, skrzyżowania imprezy masowe, dworce, lotniska i inne publiczne obszary miejskie) z użyciem transmisji i analizy treści wideo w ostatnim czasie zyskuje na znaczeniu z powodu ogólnego wzrostu przestępczości oraz aktów terroryzmu (ataki na WTC, komunikację publiczną w Londynie i Madrycie). Jakość odbioru wideo w celach użytkowych {monitoring) istotnie różni się od jakości odbioru treści wideo w celach rozrywkowych. Zasady oceny, a zwłaszcza maksymalizacji jakości wideo użytkowego, są stosunkowo nową dziedziną. Dotychczasowe rozwiązania sprowadzały się głównie do optymalizacji parametrów sieciowych OoS, względnie - dla wideo w zastosowaniach użytkowych - podejmowano próby przeniesienia metod klasycznych (stworzonych dla treści rozrywkowych) typu PSNR (Peak Signal-to-Noise Ratio) czy też SSIM (Structural S/M/anty). Przedstawiono aktualne trendy w dziedzinie jakości obrazu dla zastosowań użytkowych, istotną uwagę poświęcając pracom jednego z najbardziej wpływowych ciał w tym zakresie, jakim jest Grupa VQiPS, finansowana przez U.S. Department of Homeland Security, powołana do życia w 2008 roku. Dostrzeżono również problem ochrony obywateli przed "permanentną inwigilacją" w stylu orwellowskim, jako że monitoring publiczny jest nierozerwalnie powiązany z ingerencją w prywatność obywateli.

EN

Monitoring of public safety (traffic, intersections, mass events, stations, airports and other public urban areas) using the transmission and analysis of video content gains in the recent period on the importance of the overall increase in crime and acts of terrorism (attacks on the WTC, public transport in London and Madrid). Quality of Experience (QoE) of video content used for entertainment (digital TV, including HDTV, and multimedia on the Internet) differs materially from the QoE of surveillance video used for recognition tasks in CCTV monitoring, because in the latter case, the subjective satisfaction of the consignee shall recede in achieving the given function (event detection, object recognition). Assessment principles, and especially maximization of the surveillance video quality, arę a relatively new field. State-of-the-Art solutions were limited mainly to optimizing the network QoS parameters (bandwidth, packet loss probability), eventually, for surveillance video, classical methods (created for entertainment content), like the PSNR (Peak Signal English-to-Noise Ratio) or SSIM (Structural SIMilarity) were applied. The article presents current trends in the field of image quality for commercial applications, giving significant attention to the work of one of the most influential bodies in this field, which is the VQiPS (Video Quality in Public Safety) Workgroup, funded by the U.S. Department of Homeland Security, set up in 2008. The article also recognizes the pro-blem of protecting citizens against Orwellian style "permanent surveillance", as the monitoring of the public is inextricably linked to the intrusion of privacy.