Video data and video links in mediated communication: what do users value?

Anderson, Anne H.; Smallwood, Lucy; MacDonald, Rory; Mullin, Jim; Fleming, AnneMarie

doi:10.1006/ijhc.1999.0335

Cited by 43 publications

(21 citation statements)

References 22 publications

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“…It might be because that it is hard for people for to distinguish the temporal difference when the frame rate is larger than 15fps. This exactly matches the result in [4] Figure 5 shows the comparison among MCDE, MSE and DSCQS for different number of Huffman codes with the same target frame rate (8fps). In this figure, only MCDE decreases as the number of Huffman codes increases.…”

Section: Evaluation 31 Comparison Among Mcde Mse and Dscqssupporting

confidence: 86%

A compressed domain distortion measure for fast video transcoding

Huang

Tran

Wang

2007

Proceedings of the 15th ACM International Conference on Multimedia

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Video applications on different mobile devices are becoming increasingly popular. It is an attractive alternative to transcode a high quality non-scalable video bitstream to match constraints (such as bandwidth or processing power) of different platforms with a similar functionality as a scalable video format. In principle, such a transcoder can reduce either the bit per frame (bpf) or the frame per second (fps) of the original bitstream to meet a particular constraint. In the case that multiple candidates with different combinations of bpf and fps satisfy the constraint, an objective video quality measure is needed for the transcoder to choose the candidate with the overall best quality considering both the spatial quality (reflected by bpf) and the temporal quality (reflected by fps). Conventional measures, such as PSNR and MSE operate in the pixel-domain, require full decoding of both the original and candidate video bitstreams and are computationally very expensive. This drawback renders them unsuitable for real-time transcoding applications. To solve this problem, we propose a Mean Compressed Domain Error (MCDE) to predict the quality of the transcoded video. Experimental results show that the proposed MCDE can predict video quality accurately with a negligible computational complexity in comparison with the conventional MSE/PSNR.

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Section: Evaluation 31 Comparison Among Mcde Mse and Dscqssupporting

confidence: 86%

A compressed domain distortion measure for fast video transcoding

Huang

Tran

Wang

2007

Proceedings of the 15th ACM International Conference on Multimedia

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show abstract

“…1), the standard image of the whole remote group is kept (in the focus groups meetings, participants repeatedly expressed that this "whole room view" is very important for them), while video streams displaying individual remote participants are added. 2) Implementation: One of the groups was placed in a videoconferencing room satisfying the AccessGrid Point requirements 7 . The whole group view was recorded by a tracking camera and SHURE Easyflex EZB/C microphones provided the audio acquisition.…”

Section: Resultsmentioning

confidence: 99%

“…• Changing the size and/or resolution of the video window did not make any measurable difference either in task results or subjective view of the participants [1], [7], [8].…”

Section: Related Workmentioning

confidence: 93%

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Videoconferencing design for remote groups

Slovák

Hladká

Troubil

2007

2007 International Conference on Collaborative Computing: Networking, Applications and Worksharing (CollaborateCom 2007)

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Abstract-Videoconferencing has emerged as a popular method of remote communication. The design of a videoconferencing environment strongly influences the communication efficiency and user satisfaction. Various studies on perceived effects of videoconferencing environments and their parameters have been done, however, they primarily focused on dyadic conversation. This paper describes an exploratory study on the effects on remote groups communication. Beginning with the standard environment, a videoconferencing design has been developed iteratively according to information obtained from the experimental group. Two new videoconferencing environment designs are introduced to suit the group conversation needs better and bring the group videoconference closer to face-to-face communication.

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“…However, the frame rate does affect the perceived visual quality. The studies of subjective video quality [4,10,20,21] show that people perceive video quality degradation as the frame rate decreases. While the traditional average PSNR or MSE cannot measure the tradeoff between the frame rate and single frame quality, the works in [8,15] provide a solution, replacing the dropped frames by the previous frames to compute the average PSNR.…”

Section: Distortion Minimizationmentioning

confidence: 99%

A workload prediction model for decoding mpeg video and its application to workload-scalable transcoding

Huang

Tran

Wang

2007

Proceedings of the 15th ACM International Conference on Multimedia

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Multimedia playback is restricted by the processing power of mobile devices, and in particular, the playback quality can be degraded due to insufficient processing power. To address this problem, we propose a new workload-scalable transcoding scheme which converts a pre-recorded video bitstream into a new video bitstream that satisfies the device's workload constraint, while keeping the transcoding distortion minimal. The key of this proposed transcoding scheme lies on a new workload prediction model, which is fast, accurate and is generic enough to apply to different video formats, decoder implementations and target platforms. The main contributions of this paper include 1) a workload prediction model for decoding MPEG video based on an offline bitstream analysis method; 2) a transcoding scheme that uses the proposed model to control the decoding workload on the target device. To facilitate our transcoding scheme, we have proposed a compressed domain distortion measure (CDDM) that takes effects from both frames per second (fps) and bits per frame (bpf) into consideration. CDDM ensures the transcoded video bitstream to have the best playback quality given the device's workload constraint. Both the workload prediction model and the transcoding scheme are evaluated experimentally.

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Video data and video links in mediated communication: what do users value?

Cited by 43 publications

References 22 publications

A compressed domain distortion measure for fast video transcoding

A compressed domain distortion measure for fast video transcoding

Videoconferencing design for remote groups

A workload prediction model for decoding mpeg video and its application to workload-scalable transcoding

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