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001-es BibID:	BIBFORM054036
Első szerző:	Orosz Péter (informatikus)
Cím:	A Case-Study on Correlating Video QoS and QoE / Péter Orosz, Tamás Skopkó, Zoltán Nagy, Pál Varga, László Gyimóthi
Dátum:	2014
Megjegyzések:	Finding the correlation among Quality of Experience (QoE) for video, measured Quality of Service (QoS) parameters in the network, and objective video performance metrics is a challenging task. This paper provides some analysis results on this issue. Our motivation is that streaming media content gets dominant position in the global traffic mix within the next few years. This is mostly due to the headway of broadband connections, and the growing significance of mobile broadband. With the evolution of personal devices, demand for High Definition (HD) resolution contents is dynamically increasing. Traversing real-time media across public packet-switched networks is a complex task, especially if quality of service should be sustained. The issue gets more complicated when the traffic is forwarded through heterogeneous infrastructures. Media content with various resolutions and bitrates show different sensitivity to transmission anomalies. Our paper investigates the correlation between subjective quality assessment (i.e., Mean Opinion Score, MOS evaluation), measured QoS parameters (packet loss, jitter) and objective video performance metrics (Video Quality Metric - VQM, Structural Similarity - SSIM, Peak Signal Noise Ration - PSNR) in the context of real-time HD video streaming (i.e., IPTV and MobileTV). In twelve scenarios, packet-level perturbations were emulated in our laboratory testbed during the transmission of short video sequences with three different resolutions (480p, 720p and 1080p). Later the videos were evaluated using subjective and objective assessment methods.
ISBN:	978-1-4799-0912-4
Tárgyszavak:	Műszaki tudományok Informatikai tudományok tanulmány, értekezés video QoE subjective assessment network measurement QoS-QoE correlation Hálózatok modellezése és analízise
Megjelenés:	Proceedings of the 2014 IEEE Network Operations and Management Symposium (NOMS) / (ed.) Hanan Lutfiyya, Piotr Cholda. - p. 1-5. -
További szerzők:	Skopkó Tamás (1978-) (informatikus) Nagy Zoltán (1991-) (informatikus) Varga Pál (1974-) (villamosmérnök) Gyimóthi László (1990-) (informatikus)
Pályázati támogatás:	TÁMOP-4.2.2.C-11/1/KONV-2012-0001 TÁMOP Médiaforgalom QoS/QoE online analízise nagysebességű hálózatokban
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001-es BibID:	BIBFORM054037
Első szerző:	Orosz Péter (informatikus)
Cím:	A No-reference Voice Quality Estimation Method for Opus-based VoIP Services / Péter Orosz, Tamás Skopkó, Zoltán Nagy, Tamás Lukovics
Dátum:	2014
ISSN:	1942-2601
Megjegyzések:	By the emergence of real time media applications, correlating users' satisfaction with measured service quality is a constant challenge. Accordingly, this area was under intensive research in the last decade. Finding the correlation among Quality of Experience (QoE) for voice, measured Quality of Service (QoS) parameters in the network, and objective voice performance metrics is a key task. Most of the voice metrics use the reference content to compare the quality of the received stream. In contrast, this paper introduces a mathematical low-complexity, no-reference method that performs real-time estimation of QoE for Opus-based voice services. To determine the estimator function, we performed combined (subjective and objective) assessments to build a reference data set of 3-tuple of MOS, jitter and loss values. Applying polynomial regression, we used the reference data set to search a low-degree two-variable polynomial to hash objective QoS metrics (jitter and loss) to the subjective MOS score of the service quality. In the final phase of our investigation, we were evaluated the performance of the polynomials with a set of four audio clips.
Tárgyszavak:	Műszaki tudományok Informatikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Opus codec real-time voice QoE estimation QoS-QoE correlation Hálózatok modellezése és analízise
Megjelenés:	International Journal on Advances in Telecommunications. - 7 : 1-2 (2014), p. 12-21. -
További szerzők:	Skopkó Tamás (1978-) (informatikus) Nagy Zoltán (1991-) (informatikus) Lukovics Tamás (1989-) (informatikus)
Pályázati támogatás:	TÁMOP-4.2.2.C-11/1/KONV-2012-0001 TÁMOP Médiaforgalom QoS/QoE online analízise nagysebességű hálózatokban
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM048974
Első szerző:	Orosz Péter (informatikus)
Cím:	Performance Analysis of the Opus Codec in VoIP Environment Using QoE Evaluation / Péter Orosz, Tamás Skopkó, Zoltán Nagy, Tamás Lukovics
Dátum:	2013
Megjegyzések:	VoIP has been a focus area of network communications for more than a decade now. The presence of VoIP traffic becomes more and more significant in the global Internet traffic. Although available access bandwidth is constantly increasing, higher capacity itself cannot guarantee higher quality of experience of the VoIP service. While QoE predicting methods are under active research, audio codecs also evolved greatly. The introduction and standardization of the Opus codec in 2012 is an important milestone in the voice codec evolution and Opus will probably be a royalty-free alternative for many VoIP applications in the near future. Past studies showed that audio quality of the Opus codec is superior when compared to almost every alternative. Mean Opinion Score (MOS) is a standardized scale for rating service quality. Our paper investigates the Opus codec in VoIP environment in terms of the relation between measured network QoS parameters and MOS value gained by subjective QoE assessments.
ISBN:	978-1-61208-305-6
Tárgyszavak:	Műszaki tudományok Informatikai tudományok előadáskivonat Opus codec Speex codec VoIP communication speech quality MOS QoE evaluation Linux Hálózatok modellezése és analízise
Megjelenés:	8th International Conference on Systems and Networks Communications, ICSNC 2013, October 27-31, 2013, Venice, Italy : Proceeding / ed. Renzo Davoli, Josef Noll. - p. 89-93. -
További szerzők:	Skopkó Tamás (1978-) (informatikus) Nagy Zoltán (1991-) (informatikus) Lukovics Tamás (1989-) (informatikus)
Pályázati támogatás:	TÁMOP-4.2.2.C-11/1/KONV-2012-0001 TÁMOP Médiaforgalom QoS/QoE online analízise nagysebességű hálózatokban
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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