Skype video responsiveness to bandwidth variations

Cicco, Luca De; Mascolo, Saverio; Palmisano, Vittorio

doi:10.1145/1496046.1496065

Cited by 46 publications

(30 citation statements)

References 15 publications

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“…The ensuing bandwidth fluctuations during a vehicular trip can seriously compromise the quality of service (QoS) experienced by network applications [2]. For example, a sudden drop in the bandwidth can cause significant packet loss, thus distorting the quality of realtime interactive communication such as a Skype call [5].…”

Section: Introductionmentioning

confidence: 99%

Improving QoS in High-Speed Mobility Using Bandwidth Maps

Yao

Kanhere

Hassan

2012

IEEE Trans. on Mobile Comput.

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Abstract-It is widely evidenced that location has a significant influence on the actual bandwidth that can be expected from Wireless Wide Area Networks (WWANs), e.g., 3G. Because a fast-moving vehicle continuously changes its location, vehicular mobile computing is confronted with the possibility of significant variations in available network bandwidth. While it is difficult for providers to eliminate bandwidth disparity over a large service area, it may be possible to map network bandwidth to the road network through repeated measurements. In this paper, we report results of an extensive measurement campaign to demonstrate the viability of such bandwidth maps. We show how bandwidth maps can be interfaced with adaptive multimedia servers and the emerging vehicular communication systems that use on-board mobile routers to deliver Internet services to the passengers. Using simulation experiments driven by our measurement data, we quantify the improvement in Quality of Service (QoS) that can be achieved by taking advantage of the geographical knowledge of bandwidth provided by the bandwidth maps. We find that our approach reduces the frequency of disruptions in perceived QoS for both audio and video applications in high-speed vehicular mobility by several orders of magnitude.

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Section: Introductionmentioning

confidence: 99%

Improving QoS in High-Speed Mobility Using Bandwidth Maps

Yao

Kanhere

Hassan

2012

IEEE Trans. on Mobile Comput.

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“…Many efforts have been made for measuring Skype's performance in congested networks. Cicco et al have performed detailed analysis of Skype's congestion control schemes for both audio [11] and video [12]. Zhang et al have studied how Skype adjusts its behavior under different stationary network conditions and have shown Skype's TCP friendliness by considering the probability that a user hangs up a call using mean opinion scores (MOS) derived from ITU G.1070 [41].…”

Section: Related Workmentioning

confidence: 99%

Exploiting just-noticeable difference of delays for improving quality of experience in video conferencing

Wah

2013

Proceedings of the 4th ACM Multimedia Systems Conference

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This paper proposes a novel approach for improving the quality of experience (QoE) of real-time video conferencing systems. In these systems, QoE is affected by signal quality as well as interactivity, both depending on the packet loss rate, delay jitters, and mouth-toear delay (MED) that measures the sender-receiver delay on audio signals (and will be the same as that of video signals when video and audio is synchronized). We notice in the current Internet that increasing MED as well as reducing packet rate can help reduce the delay-aware loss rate in congested connections. Between the two methods, the former plays a more important role and applies well to a variety of network conditions for improving audiovisual signal quality, although overly increasing the MED will degrade interactivity. Based on a psychophysical concept called just-noticeable difference (JND), we find the extent to which MED can be increased, without humans perceiving the difference from the original conversation. The approach can be applied to improve existing video conferencing systems. Starting from the operating point of an existing system, we increase its MED to within JND in order to have more room for smoothing network delay spikes as well as recovering lost packets, without incurring noticeable degradation in interactivity. We demonstrate the idea on Skype and Windows Live Messenger by designing a traffic interceptor to extend their buffering time and to perform packet scheduling/recovery. Our experimental results show significant improvements in QoE, with much better signal quality while maintaining similar interactivity.

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“…The high data rate cost of using FaceTime over limited data plans can quickly become expensive [7]. Other mobile video chat apps, like Skype, transmit video at lower dynamic transmission rates ranging from 40-450 kilobits per second (kbps) depending on network traffic [11]. Video intelligibility is sacrificed when relying on the available network bandwidth to regulate video transmission rates.…”

Section: Introductionmentioning

confidence: 99%

Analyzing the intelligibility of real-time mobile sign language video transmitted below recommended standards

Tran

Flowers

Risken

et al. 2014

Proceedings of the 16th International ACM SIGACCESS Conference on Computers &Amp; Accessibility - ASSETS '14

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Mobile sign language video communication has the potential to be more accessible and affordable if the current recommended video transmission standard of 25 frames per second at 100 kilobits per second (kbps) as prescribed in the International Telecommunication Standardization Sector (ITU-T) Q.26/16 were relaxed. To investigate sign language video intelligibility at lower settings, we conducted a laboratory study, where fluent ASL signers in pairs held real-time free-form conversations over an experimental smartphone app transmitting real-time video at 5 fps/25 kbps, 10 fps/50 kbps, 15 fps/75 kbps, and 30 fps/150 kbps, settings well below the ITU-T standard that save both bandwidth and battery life. The aim of the laboratory study was to investigate how fluent ASL signers adapt to the lower video transmission rates, and to identify a lower threshold at which intelligible realtime conversations could be held. We gathered both subjective and objective measures from participants and calculated battery life drain. As expected, reducing frame rate monotonically extended battery life. We discovered all participants were successful in holding intelligible conversations across all frame rates. Participants did perceive the lower quality of video transmitted at 5 fps/25 kbps and felt that they were signing more slowly to compensate; however, participants' rate of fingerspelling did not actually decrease. This and other findings support our recommendation that intelligible mobile sign language conversations can occur at frame rates as low as 10 fps/50 kbps while optimizing resource consumption, video intelligibility, and user preferences.

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Skype video responsiveness to bandwidth variations

Abstract: The TCP/IP stack has been extremely successful for reliable delivery of best-eort, time insensitive elastic type data trafc. Nowadays, the Internet is rapidly evolving to become an equally ecient platform for multimedia content delivery.

Cited by 46 publications

References 15 publications

Improving QoS in High-Speed Mobility Using Bandwidth Maps

Improving QoS in High-Speed Mobility Using Bandwidth Maps

Exploiting just-noticeable difference of delays for improving quality of experience in video conferencing

Analyzing the intelligibility of real-time mobile sign language video transmitted below recommended standards

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