Wyniki wyszukiwania - BazTech

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User experience evaluation study on the quality of 1K, 2K, and 4K H.265/HEVC video content

Falkowski-Gilski Przemyslaw, Uhl Tadeus, Hoppe Christian

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2024

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nr 77 (149)

38--46

EN

Nowadays, most content creators focus on distributing rich media at the highest possible resolution. Currently, the majority of sold consoles, media players, computer hardware, as well as displays and TVs are advertised as 4K-compatible. The same trend is observed in the case of popular online streaming services and terrestrial TV broadcasts. Generally speaking, it is assumed that higher bitrates provide higher subjective judgements. In this paper, we present the results of a user experience (UX) evaluation study on the quality of video content coded and transmitted in different resolutions in the internet protocol (IP) environment. The image resolutions include 1K (1920×1080 pixels; full-HD), 2K (2560×1440 pixels; wide-QHD), and 4K (3840×2160 pixels; ultra-HD) content that are processed in the H.265/HEVC (high-efficiency video coding) format. A subjective evaluation is carried out in a laboratory consisting of 20 iMacs with a 21.5-inch 4K Retina (4096×2304 pixels) display. The group of viewers included 28 individuals aged between 21‒35 years old, comprising people with and without visual impairments. The obtained UX results are compared with previous experiments, including both objective quality of service (QoS) and subjective quality of experience (QoE), as well as the impact of downscaling to 1K from 2K and 4K. The outcomes of this study may be of particular interest to any party interested in video content processing and distribution, as well as consumption and storage.

2

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.

3

Choosing of typhlocommentator, description of subject in videocontent for sightless and visually impaired person

Demchuk A., Lytvyn V.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2015

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Vol. 4, No 1

25--29

EN

The statement of problem of choosing of typhlocommentator is considered in this article, the description of the subject among the number of possible typhlocommentator. The mathematic model of such a task is given and an approach of solving it has been worked out. When researching the problem of access of weak-sight people to the video content, it is required to understand that more than a most part of the information is provided to the viewer in the form of an image. Yes, blind people hear all words of actors, sounds of the environment, processes at the screen, but it is difficult for them to identify the person to whom the specific words belong, what happens with heroes at the very specific moment, what is depicted in the given scene, it is difficult for them to understand reaction of actors, which the latter often express with the help of movements or mimics. Typhlocomments to video content for blind people and people with weak-sight are one of the real steps towards solution of the problem of limitation of access to such content.