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Nawaz, O., Fiedler, M. & Khatibi, S. (2024). QoE-Based Performance Comparison of AVC, HEVC, and VP9 on Mobile Devices with Additional Influencing Factors. Electronics, 13(2), Article ID 329.
Open this publication in new window or tab >>QoE-Based Performance Comparison of AVC, HEVC, and VP9 on Mobile Devices with Additional Influencing Factors
2024 (English)In: Electronics, E-ISSN 2079-9292, Vol. 13, no 2, article id 329Article in journal (Refereed) Published
Abstract [en]

While current video quality assessment research predominantly revolves around resolutions of 4 K and beyond, targeted at ultra high-definition (UHD) displays, effective video quality for mobile video streaming remains primarily within the range of 480 p to 1080 p. In this study, we conducted a comparative analysis of the quality of experience (QoE) for widely implemented video codecs on mobile devices, specifically Advanced Video Coding (AVC), its successor High-Efficiency Video Coding (HEVC), and Google’s VP9. Our choice of 720 p video sequences from a newly developed database, all with identical bitrates, aimed to maintain a manageable subjective assessment duration, capped at 35–40 min. To mimic real-time network conditions, we generated stimuli by streaming original video clips over a controlled emulated setup, subjecting them to eight different packet-loss scenarios. We evaluated the quality and structural similarity of the distorted video clips using objective metrics, including the Video Quality Metric (VQM), Peak Signal-to-Noise Ratio (PSNR), Video Multi-Method Assessment Fusion (VMAF), and Multi-Scale Structural Similarity Index (MS-SSIM). Subsequently, we collected subjective ratings through a custom mobile application developed for Android devices. Our findings revealed that VMAF accurately represented the degradation in video quality compared to other metrics. Moreover, in most cases, HEVC exhibited an advantage over both AVC and VP9 under low packet-loss scenarios. However, it is noteworthy that in our test cases, AVC outperformed HEVC and VP9 in scenarios with high packet loss, based on both subjective and objective assessments. Our observations further indicate that user preferences for the presented content contributed to video quality ratings, emphasizing the importance of additional factors that influence the perceived video quality of end users. © 2024 by the authors.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
HEVC and AVC comparison, mobile codecs efficiency, multimedia streaming, QoE IFs, QoE metrics, video quality assessments
National Category
Communication Systems
Identifiers
urn:nbn:se:bth-25939 (URN)10.3390/electronics13020329 (DOI)001148927000001 ()2-s2.0-85183182089 (Scopus ID)
Funder
Swedish Research Council
Available from: 2024-02-05 Created: 2024-02-05 Last updated: 2024-02-13Bibliographically approved
Kelkkanen, V., Lindero, D., Fiedler, M. & Zepernick, H.-J. (2023). Hand-Controller Latency and Aiming Accuracy in 6-DOF VR. Advances in Human-Computer Interaction, Article ID 1563506.
Open this publication in new window or tab >>Hand-Controller Latency and Aiming Accuracy in 6-DOF VR
2023 (English)In: Advances in Human-Computer Interaction, ISSN 1687-5893, E-ISSN 1687-5907, article id 1563506Article in journal (Refereed) Published
Abstract [en]

All virtual reality (VR) systems have some inherent hand-controller latency even when operated locally. In remotely rendered VR, additional latency may be added due to the remote transmission of data, commonly conducted through shared low-capacity channels. Increased latency will negatively affect the performance of the human VR operator, but the level of detriment depends on the given task. This work quantifies the relations between aiming accuracy and hand-controller latency, virtual target speed, and the predictability of the target motion. The tested context involves a target that changes direction multiple times while moving in straight lines. The main conclusions are, given the tested context, first, that the predictability of target motion becomes significantly more important as latency and target speed increase. A significant difference in accuracy is generally observed at latencies beyond approximately 130 ms and at target speeds beyond approximately 3.5 degrees/s. Second, latency starts to significantly impact accuracy at roughly 90 ms and approximately 3.5 degrees/s if the target motion cannot be predicted. If it can, the numbers are approximately 130 ms and 12.7 degrees/s. Finally, reaction times are on average 190-200 ms when the target motion changes to a new and unpredictable direction.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2023
Keywords
Tracking, Robot, Artificial intelligence
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:bth-24387 (URN)10.1155/2023/1563506 (DOI)001077344100001 ()2-s2.0-85174505323 (Scopus ID)
Funder
Knowledge Foundation, 20170056Knowledge Foundation, 20220068
Available from: 2023-03-21 Created: 2023-03-21 Last updated: 2023-11-09Bibliographically approved
Sundstedt, V., Boeva, V., Zepernick, H.-J., Goswami, P., Cheddad, A., Tutschku, K., . . . Arlos, P. (2023). HINTS: Human-Centered Intelligent Realities. In: Håkan Grahn, Anton Borg and Martin Boldt (Ed.), 35th Annual Workshop of the Swedish Artificial Intelligence Society SAIS 2023: . Paper presented at 35th Annual Workshop of the Swedish Artificial Intelligence Society SAIS 2023, Karlskrona, June 12-13, 2023 (pp. 9-17). Linköping University Electronic Press
Open this publication in new window or tab >>HINTS: Human-Centered Intelligent Realities
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2023 (English)In: 35th Annual Workshop of the Swedish Artificial Intelligence Society SAIS 2023 / [ed] Håkan Grahn, Anton Borg and Martin Boldt, Linköping University Electronic Press, 2023, p. 9-17Conference paper, Published paper (Refereed)
Abstract [en]

During the last decade, we have witnessed a rapiddevelopment of extended reality (XR) technologies such asaugmented reality (AR) and virtual reality (VR). Further, therehave been tremendous advancements in artificial intelligence(AI) and machine learning (ML). These two trends will havea significant impact on future digital societies. The vision ofan immersive, ubiquitous, and intelligent virtual space opensup new opportunities for creating an enhanced digital world inwhich the users are at the center of the development process,so-calledintelligent realities(IRs).The “Human-Centered Intelligent Realities” (HINTS) profileproject will develop concepts, principles, methods, algorithms,and tools for human-centered IRs, thus leading the wayfor future immersive, user-aware, and intelligent interactivedigital environments. The HINTS project is centered aroundan ecosystem combining XR and communication paradigms toform novel intelligent digital systems.HINTS will provide users with new ways to understand,collaborate with, and control digital systems. These novelways will be based on visual and data-driven platforms whichenable tangible, immersive cognitive interactions within realand virtual realities. Thus, exploiting digital systems in a moreefficient, effective, engaging, and resource-aware condition.Moreover, the systems will be equipped with cognitive featuresbased on AI and ML, which allow users to engage with digitalrealities and data in novel forms. This paper describes theHINTS profile project and its initial results. ©2023, Copyright held by the authors   

Place, publisher, year, edition, pages
Linköping University Electronic Press, 2023
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 199
National Category
Human Computer Interaction
Identifiers
urn:nbn:se:bth-25413 (URN)10.3384/ecp199001 (DOI)9789180752749 (ISBN)
Conference
35th Annual Workshop of the Swedish Artificial Intelligence Society SAIS 2023, Karlskrona, June 12-13, 2023
Funder
Knowledge Foundation, 20220068
Available from: 2023-09-22 Created: 2023-09-22 Last updated: 2023-12-28Bibliographically approved
Chu, T. M., Fiedler, M., Kelkkanen, V., Lindero, D. & Zepernick, H.-J. (2023). On the Perception of Frame Stalls in Remote VR for Task and Task-Free Subjective Tests. In: 2023 15th International Conference on Quality of Multimedia Experience, QoMEX 2023: . Paper presented at 15th International Conference on Quality of Multimedia Experience, QoMEX 2023, Ghent, 20-22 June 2023. (pp. 201-204). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>On the Perception of Frame Stalls in Remote VR for Task and Task-Free Subjective Tests
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2023 (English)In: 2023 15th International Conference on Quality of Multimedia Experience, QoMEX 2023, Institute of Electrical and Electronics Engineers (IEEE), 2023, p. 201-204Conference paper, Published paper (Refereed)
Abstract [en]

The performance of remotely rendered Virtual Reality (VR) is sensitive to temporal disturbances in communication channels. An earlier Quality of Experience (QoE) study of temporal impacts in the form of frame stalls has revealed difficulties with subjective disturbance ratings while performing a task in an interactive 6-degrees-of-freedom (DOF) VR environment. This study follows up on above observation by comparing QoE ratings in the presence and absence of a task. The exploratory findings show that the task-free subjective tests yield lower ratings compared to the subjective tests with task. This indicates that the participants became more sensitive to temporal impairments in the absence of a task. Also, the positive impact of reprojection on the QoE ratings decreased in the task-free environment. The simulator sickness results for individual symptoms were on similar low levels in both settings. The total score (TS) of sickness severity was higher after than before the subjective tests with task while the difference between the TS before and after the task-free subjective tests was insignificant, © 2023 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Series
International Workshop on Quality of Multimedia Experience (QoMEX), ISSN 2372-7179, E-ISSN 2472-7814
Keywords
Diseases, Subjective testing, Virtual reality, 6 degree of freedom, Communications channels, Follow up, Performance, Re-projection, Simulator sickness, Quality of service
National Category
Computer Sciences Other Medical Sciences not elsewhere specified
Identifiers
urn:nbn:se:bth-25320 (URN)10.1109/QoMEX58391.2023.10178492 (DOI)001037196100040 ()2-s2.0-85167358478 (Scopus ID)9798350311730 (ISBN)
Conference
15th International Conference on Quality of Multimedia Experience, QoMEX 2023, Ghent, 20-22 June 2023.
Funder
Knowledge Foundation, 20170056Knowledge Foundation, 20220068
Available from: 2023-08-24 Created: 2023-08-24 Last updated: 2023-09-15Bibliographically approved
Fiedler, M. (2023). Årets lärare 2022: Fördern & fordern / Att stödja & kräva. Karlskrona: Blekinge Tekniska Högskola
Open this publication in new window or tab >>Årets lärare 2022: Fördern & fordern / Att stödja & kräva
2023 (Swedish)Report (Other (popular science, discussion, etc.))
Abstract [sv]

1.    ”Fördern” (att stödja) på tyska används på många sätt inom lärande: för att ta hand om högbegåvade eller om de som har inlärningssvårigheter, eller för att möjliggöra studier överhuvudtaget (genom CSN). Här ser jag min ena roll som influencer och coach.

2.    ”Fordern” (att kräva) går ut på att studenterna får visa vad de går för, under olika ändamålsenliga examinationsformer, men med stor respekt för studenternas prestationer. Här ser jag min andra roll som examinator.

Place, publisher, year, edition, pages
Karlskrona: Blekinge Tekniska Högskola, 2023. p. 1
Series
Blekinge Tekniska Högskola Best practice ; 45
Keywords
årets lärare, stödja och kräva, pedagogik, didaktik
National Category
Didactics Learning Pedagogy Pedagogical Work
Identifiers
urn:nbn:se:bth-25664 (URN)
Available from: 2023-11-29 Created: 2023-11-29 Last updated: 2023-12-04Bibliographically approved
Kelkkanen, V., Lindero, D., Fiedler, M., Zepernick, H.-J. & Chu, T. M. (2022). QoE of Frame Stalls in Remote 6-DOF VR. In: International Conference on Quality of Multimedia Experience, QoMEX 2022: . Paper presented at 14th International Conference on Quality of Multimedia Experience, QoMEX 2022, Lippstadt 5-7 September, 2022.. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>QoE of Frame Stalls in Remote 6-DOF VR
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2022 (English)In: International Conference on Quality of Multimedia Experience, QoMEX 2022, Institute of Electrical and Electronics Engineers (IEEE), 2022Conference paper, Published paper (Refereed)
Abstract [en]

Remotely rendered Virtual Reality (VR) typically has to rely upon less capable and less reliable communication channels as compared to locally rendered VR. Such communication channels pose the risk of impairing the VR experience with temporary disturbances in form of frame stalls that would not be present in local VR. However, it is not obvious to which extent the durations of temporary stalls affect the Quality of Experience (QoE) in interactive 6-degrees-of-freedom (DOF) VR, and neither to which extent present reprojection/warping techniques mitigate any adverse effects of such stalls on user perception.

In this paper, subjective experiments were conducted with N =29 users to quantify the relationship between QoE and single, isolated stall durations in interactive 6-DOF remote VR when stalls either freeze the frame in place, or when frames are reprojected by the VR driver. Results indicate that given a 90 fps headset and a simple task that requires moderate head-movement; (1) short, isolated stalls of up to 4 frames go unnoticed on average, no matter whether reprojection is used or not, (2) the number of perceived stalls when using reprojection is the same or lower than the reference (no stall) in the range 1-4 frame stalls, (3) reprojection entails significantly higher user ratings for stalls ranging from 8 frames and beyond, (4) the improvement of using reprojection over freezes in terms of making more stalling events imperceptible is highest in the range 8-16 frames. © 2022 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2022
Series
International Workshop on Quality of Multimedia Experience (QoMEX), ISSN 2372-7179, E-ISSN 2472-7814
Keywords
Communication channels (information theory), Quality of service, 4-frames, 6 degree of freedom, Adverse effect, Communications channels, Re-projection, Reliable communication, Subjective experiments, User perceptions, Virtual reality experiences, Warping techniques, Virtual reality
National Category
Computer Sciences
Identifiers
urn:nbn:se:bth-24016 (URN)10.1109/QoMEX55416.2022.9900899 (DOI)2-s2.0-85141692740 (Scopus ID)9781665487948 (ISBN)
Conference
14th International Conference on Quality of Multimedia Experience, QoMEX 2022, Lippstadt 5-7 September, 2022.
Available from: 2022-12-01 Created: 2022-12-01 Last updated: 2023-09-15Bibliographically approved
Zepernick, H.-J., Fiedler, M., Chu, T. M. & Kelkkanen, V. (2022). Video Freeze Assessment of TPCAST Wireless Virtual Reality: An Experimental Study. Applied Sciences, 12(3), Article ID 1733.
Open this publication in new window or tab >>Video Freeze Assessment of TPCAST Wireless Virtual Reality: An Experimental Study
2022 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 12, no 3, article id 1733Article in journal (Refereed) Published
Abstract [en]

Wireless virtual reality (VR) offers a seamless user experience but has to cope with higher sensitivity to temporal impairments induced on the wireless link. Apart from bandwidth dynamics and latency, video freezes and their lengths are important temporal performance indicators that impact on the quality of experience (QoE) of networked VR applications and services. This paper reports an experimental study that focuses on the VR video frame freeze length characteristics of a wireless VR solution. A comprehensive measurement campaign using a commercial TPCAST wireless VR solution with an HTC Vive head-mounted display was conducted to obtain real VR video traces. The number of detected freezes and freeze intensities are reported both accumulated over four room quadrants as well as for each of the four quadrants subject to six transmitter-receiver distances. The statistical analysis of the VR video traces of the different experiments includes histograms of the freeze lengths and cumulative complementary histograms of the freeze length. The results of this analysis offer insights into the density of the underlying distributions of the measured data, illustrate the impact of the room topology on the freeze characteristics, and suggest the statistical modeling of the freeze characteristics as exponential and geometric distributions. The statistical models of the freeze characteristics may be included in wireless VR simulators supporting the development of physical layer, medium access layer, and higher layer functionalities. They also may serve as network-disturbance models for VR QoE studies, e.g., generating realistic freeze events in wireless VR stimuli. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
Head-mounted display, TPCAST wireless adapter, Video freeze analysis, Video freezes, VR video, Wireless virtual reality, WirelessHD
National Category
Telecommunications
Identifiers
urn:nbn:se:bth-22669 (URN)10.3390/app12031733 (DOI)000757411400001 ()2-s2.0-85124452970 (Scopus ID)
Funder
Knowledge Foundation, 20170056
Note

open access

Available from: 2022-02-25 Created: 2022-02-25 Last updated: 2022-03-11Bibliographically approved
Doering, N., De Moor, K., Fiedler, M., Schoenenberg, K. & Raake, A. (2022). Videoconference Fatigue: A Conceptual Analysis. International Journal of Environmental Research and Public Health, 19(4)
Open this publication in new window or tab >>Videoconference Fatigue: A Conceptual Analysis
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2022 (English)In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 19, no 4Article in journal (Refereed) Published
Abstract [en]

Videoconferencing (VC) is a type of online meeting that allows two or more participants from different locations to engage in live multi-directional audio-visual communication and collaboration (e.g., via screen sharing). The COVID-19 pandemic has induced a boom in both private and professional videoconferencing in the early 2020s that elicited controversial public and academic debates about its pros and cons. One main concern has been the phenomenon of videoconference fatigue. The aim of this conceptual review article is to contribute to the conceptual clarification of VC fatigue. We use the popular and succinct label "Zoom fatigue" interchangeably with the more generic label "videoconference fatigue" and define it as the experience of fatigue during and/or after a videoconference, regardless of the specific VC system used. We followed a structured eight-phase process of conceptual analysis that led to a conceptual model of VC fatigue with four key causal dimensions: (1) personal factors, (2) organizational factors, (3) technological factors, and (4) environmental factors. We present this 4D model describing the respective dimensions with their sub-dimensions based on theories, available evidence, and media coverage. The 4D-model is meant to help researchers advance empirical research on videoconference fatigue.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
video call, Zoom, Skype, Cisco Webex, Microsoft Teams, Big Blue Button, exhaustion, COVID-19 pandemic, computer-mediated communication, face-to-face-communication, MEDIA RICHNESS, SPEECH-INTELLIGIBILITY, VIRTUAL MEETINGS, MENTAL FATIGUE, VISUAL FATIGUE, COVID-19, COMMUNICATION, WORKING, LOAD, TECHNOSTRESS
National Category
Public Health, Global Health, Social Medicine and Epidemiology
Identifiers
urn:nbn:se:bth-22807 (URN)10.3390/ijerph19042061 (DOI)000769121800001 ()35206250 (PubMedID)
Note

open access

Available from: 2022-04-01 Created: 2022-04-01 Last updated: 2022-04-01Bibliographically approved
Kelkkanen, V., Lindero, D., Zepernick, H.-J., Fiedler, M. & Chu, T. M. (2022). VRstalls: A Dataset on the QoE of Frame Stalls in 6-DOF VR. In: 2022 14th International Conference on Quality of Multimedia Experience, QoMEX 2022: . Paper presented at 2022 14th International Conference on Quality of Multimedia Experience, QoMEX 2022, Lippstadt, 5 September through 7 September 2022. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>VRstalls: A Dataset on the QoE of Frame Stalls in 6-DOF VR
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2022 (English)In: 2022 14th International Conference on Quality of Multimedia Experience, QoMEX 2022, Institute of Electrical and Electronics Engineers (IEEE), 2022Conference paper, Published paper (Refereed)
Abstract [en]

A dataset has been created from an experiment regarding the subjective Quality of Experience (QoE) in relation to stalling video feeds in interactive 6-Degrees-of-freedom Virtual Reality (6-DOF VR). The main purpose of collecting this data is to provide insight into the QoE of stalls that may occur in interactive remote-rendered 6-DOF VR. The data contains information regarding user ratings coupled with various stall lengths and for both frozen or reprojected images. Additionally, user motion and pixel changes (in the form of Mean Square Errors) in successive images in the vicinity of the stall are also stored. In summary, 29 users participated in testing, each rating 16 scenes, amounting to a total of 464 rated scenes. © 2022 IEEE.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2022
Series
International Workshop on Quality of Multimedia Experience (QoMEX), ISSN 2372-7179, E-ISSN 2472-7814
Keywords
Quality of service, Virtual reality, 6 degree of freedom, Means square errors, Subjective quality, User motion, User rating, Mean square error
National Category
Media Engineering
Identifiers
urn:nbn:se:bth-23983 (URN)10.1109/QoMEX55416.2022.9900895 (DOI)2-s2.0-85141736105 (Scopus ID)9781665487948 (ISBN)
Conference
2022 14th International Conference on Quality of Multimedia Experience, QoMEX 2022, Lippstadt, 5 September through 7 September 2022
Available from: 2022-11-24 Created: 2022-11-24 Last updated: 2023-09-15Bibliographically approved
Minhas, T. N. & Fiedler, M. (2021). Mitigation of the Effects of Network Outage on Video QoE Using a Sender Buffer. Electronics, 10(10), Article ID 1209.
Open this publication in new window or tab >>Mitigation of the Effects of Network Outage on Video QoE Using a Sender Buffer
2021 (English)In: Electronics, E-ISSN 2079-9292, Vol. 10, no 10, article id 1209Article in journal (Refereed) Published
Abstract [en]

With the growth of multimedia applications and the mobile Internet, quality sense and quality expectation of the end-user are rising rapidly. A small notable distortion in the multimedia applications may degrade the degree of delight of the user, who is very considerate of the video Quality of Experience (QoE). During live streaming, a network outage may result in video freezes and video jumps. To dampen the impact of a network outage on the video QoE, we propose the use of a well-sized sender buffer. We present the concept, derive key analytical relations, and perform a set of subjective tests. Based on those, we report a significant enhancement of user ratings due to the proposed sender buffer in the presence of network outages.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
quality of experience, network outage, video streaming, sender buffer, user experiments
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:bth-21838 (URN)10.3390/electronics10101209 (DOI)000654901400001 ()
Note

open access

Available from: 2021-06-28 Created: 2021-06-28 Last updated: 2022-04-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8929-4911

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