Adaptive playout mechanisms for packetized audio applications in wide-area networks

Ramjee, Ramachandran; Kurose, James F.; Towsley, Don; Schulzrinne, Henning

doi:10.1109/infcom.1994.337672

Cited by 347 publications

(311 citation statements)

References 11 publications

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“…To the best of our knowledge, the subjective results presented in [5] are a first proof of the assertion published frequently in the literature [1,2,6] that playout adjustments, typical of those introduced by jitter buffers in VoIP scenarios do not have a noticeable effect on quality perceived by the end user. It has been also found in [5] that such playout adjustments have however a significant impact on objective MOS scores predicted by the PESQ model [7,8].…”

Section: Introductionsupporting

confidence: 52%

“…The former make use of silence periods within natural speech and adapt such silences to track network conditions, thus preserving the integrity of active speech talkspurts. Examples of this approach are described in [1,2]. Per packet strategies are different in that adjustments are made both during silence periods and during talkspurts by time-scaling of packets, a technique also known in the literature as time-warping.…”

Section: Introductionmentioning

confidence: 99%

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Detailed comparative analysis of PESQ and VISQOL behaviour in the context of playout delay adjustments introduced by VOIP jitter buffer algorithms

Hines

Počta

Melvin

2013

2013 Fifth International Workshop on Quality of Multimedia Experience (QoMEX)

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This paper undertakes a detailed comparative analysis of both PESQ and VISQOL model behaviour, when tested against speech samples modified through playout delay adjustments. The adjustments are typical (in extent and magnitude) to those introduced by VoIP jitter buffer algorithms. Furthermore, the analysis examines the impact of adjustment location as well as speaker factors on MOS scores predicted by both models and seeks to determine if both models are able to correctly predict the impact on quality perceived by the end user from earlier subjective tests. The earlier results showed speaker voice preference and potentially wideband experience dominating subjective tests more than playout delay adjustment duration or location. By design, PESQ and VISQOL do not qualify speaker voice difference reducing their correlation with the subjective tests. In addition, it was found that PESQ scores are impacted by playout delay adjustments and thus the impact of playout delay adjustments on a quality perceived by the end user is not well modelled. On the other hand, VISQOL model is better in predicting an impact of playout delay adjustments on a quality perceived by the user but there are still some discrepancies in the predicted scores. The reasons for those discrepancies are particularly analysed and discussed.

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Section: Introductionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Detailed comparative analysis of PESQ and VISQOL behaviour in the context of playout delay adjustments introduced by VOIP jitter buffer algorithms

Hines

Počta

Melvin

2013

2013 Fifth International Workshop on Quality of Multimedia Experience (QoMEX)

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“…where p i is the buffer size for packet i + 1, n i is the network delay of packet i, and α = β = 1−0.998002 according to [20].…”

Section: A Methodologymentioning

confidence: 99%

Toward an understanding of the processing delay of peer-to-peer relay nodes

Chen

Lou

2008

2008 IEEE International Conference on Dependable Systems and Networks With FTCS and DCC (DSN)

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Abstract-Peer-to-peer relaying is commonly used in realtime applications to cope with NAT and firewall restrictions and provide better quality network paths. As relaying is not natively supported by the Internet, it is usually implemented at the application layer. Also, in a modern operating system, the processor is shared, so the receive-process-forward process for each relay packet may take a considerable amount of time if the host is busy handling some other tasks. Thus, if we happen to select a loaded relay node, the relaying may introduce significant delays to the packet transmission time and even degrade the application performance.In this work, based on an extensive set of Internet traces, we pursue an understanding of the processing delays incurred at relay nodes and their impact on the application performance. Our contribution is three-fold: 1) we propose a methodology for measuring the processing delays at any relay node on the Internet; 2) we characterize the workload patterns of a variety of Internet relay nodes; and 3) we show that, serious VoIP quality degradation may occur due to relay processing, thus we have to monitor the processing delays of a relay node continuously to prevent the application performance from being degraded.

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“…The delay introduced by jitter buffers B u and B d can be fixed if a fixed size jitter buffer is used or can vary if an adaptive jitter buffer is used. TestYourVoIP implements an adaptive jitter buffer based on [3]. The verifiers measure the average jitter buffer delay and include the measured value in the voice latency they report.…”

Section: Cmos Degradation Factorsmentioning

confidence: 99%

Voice Quality on the Internet in 2005 as Measured by www.TestYourVoIP.com

Sylor¹,

Venna²,

Ripps³

2006

Lecture Notes in Computer Science

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Abstract. How well can the Internet serve as a network carrying voice calls? To answer that question, we have been running a web site called TestYourVoIP where users can run tests of VoIP Quality from their PC. In this paper we describe how TestYourVoIP operates, the kinds of tests it performs, and the results we have found from those tests. Our findings indicate that while many users will get acceptable call quality, too many will not. We offer some insights as to the reasons for poor quality based on these real world experiences. Lastly, we note that over 2005, voice quality on the Internet has gotten worse.

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Adaptive playout mechanisms for packetized audio applications in wide-area networks

Cited by 347 publications

References 11 publications

Detailed comparative analysis of PESQ and VISQOL behaviour in the context of playout delay adjustments introduced by VOIP jitter buffer algorithms

Detailed comparative analysis of PESQ and VISQOL behaviour in the context of playout delay adjustments introduced by VOIP jitter buffer algorithms

Toward an understanding of the processing delay of peer-to-peer relay nodes

Voice Quality on the Internet in 2005 as Measured by www.TestYourVoIP.com

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