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OPTICOM, the leading provider of signal based perceptual measurement technology for voice, audio and video, offers its new easy to use
PEVQ V 2.0 measurement as an OEM solution. PEVQ evaluates the quality of CIF, QCIF, VGA and Rec. 601 video formats based on perceptual measurement, reliably, objectively and fast.
PEVQ is based on the earlier PVQM technologydeveloped by KPN Research and new develop-ments of OPTICOM.
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click to [ enlarge picture ]
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Accurate, reliable and fast objective analysis of perceived video quality |
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Full reference based end-to-end quality analysis |
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Outputs MOS score that correlates well with subjective MOS |
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Additional KPIs for detailed analysis |
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Measurement of multimedia (QCIF, CIF, VGA), SD and HD video quality |
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Applications: IPTV, streaming video, 3G, video telephony |
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Performance benchmarked by the Video Quality Experts Group (VQEG) and approved as new ITU-T Rec. J.247 (2008) |
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The algorithm can be divided up into four separate blocks. The first block – pre-processing stage – is responsible for the spatial and temporal alignment of the reference and the impaired signal. This process ensures that only corresponding frames are compared to each other.
The second block calculates the perceptual difference of the aligned signals. Perceptual means that only those differences are taken into account which are actually perceived by a human viewer. Furthermore the activity of the motion in the reference signal provides another indicator representing the temporal information.
This indicator is important as it takes into account that in frame series with low activity the perception of details is much higher than in frame series with quick motion.
The third block in the figure classifies the previously calculated indicators and detects certain types of distortions.
Finally, in the fourth block all the appropriate indicators according to the detected distortions are aggregated, forming the final result - the mean opinion score (MOS). The MOS value describes the video quality on a range from 1 for very bad quality, to 5 for excellent quality.
Besides the final quality score additional indicators are provided at the output of the algorithm for further cause analysis.
This approach to video quality estimation includes the effects of both packet level impairments (loss, jitter) and signal related impairments such as blockiness, jerkiness, blur and distortions caused by coding processes.
Future releases will be further optimized in computational performance and prediction accuracy to provide a complete picture of a quality estimate. OPTICOM’s roadmap for PEVQ targets at candidating in the competition of the Video Quality Experts Group (VQEG) for the best video quality measurement model.
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| Functionality |
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Perceptual Evaluation of Video Quality-PEVQ, with mapping to MOS scale (1 bad, ... 5 excellent quality) |
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Analysis of multimedia, SD and HD video formats |
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| Input data |
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Raw YUV, AVI Files with RGB24, YUV444, YUV422 or YUV420 data, any frame rate from 2,5 up to 60 fps |
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Video test sequences of 6 to 20 seconds duration |
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| Complexity |
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PEVQ is widely optimized and is capable of processing QCIF streams faster than realtime on a 3GHz Pentium 4 machine. |
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| Platforms |
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Windows |
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Linux |
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PEVQ MOS
The PEVQ MOS value lies within a range from 1 (bad) to 5 (excellent). The PEVQ MOS is based on a multitude of perceptually motivated parameters and is calculated according to ITU-T Rec. J.247. |
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Distortion indicators
For a more detailed analysis the perceptual level of distortion in the luminance, chrominance and temporal domain are provided. |
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Delay
The delay of each frame of the test signal related to the reference signal. |
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Brightness
The brightness of the reference and degraded signal. |
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Contrast
The contrast of the distorted and the reference sequence. |
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PSNR
To allow for a coarse analysis of distortions in different domains the PSNR is provided for the Y, Cb and Cr components separately. |
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Jerkiness
describes the smoothness of a video playback which is often impaired by down-sampling, coding processes and perturbed transmissions. |
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Blur
is a distortion characterized by reduced sharpness of contour edges and spatial detail. |
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Blockiness
is often the result of a low bit rate coding that uses a block matching algorithm for the motion estimation and a coarse quantization for the image blocks. |
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Frame Skips and Freezes
are temporal artefacts occurring in video transmissions caused by e.g. overloaded networks. |
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Effective Frame Rate
Down-sampling of a video signal on a frame by frame basis often results in loss of information which often leads to the degradation of the video signal. The effective frame rate is an indicator quantifying the severeness of such a process. |
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Temporal and Spacial Activity
Temporal and spacial activity indicators quantify the amount of activity /movement in the video content. These indicators are derived from ITU-T recommendation P.910.
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| > Download more detailed information |
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Download "PEVQ™ Advanced Perceptual Evaluation of Video Quality"
[as PDF / 360 kb] |
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| > www.PEVQ.org |
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OPTICOM's new web portal comprises an up-to-date listing on commercially available video quality testing tools which can analyze the picture quality by providing a MOS score, just as subscribers would perceive the quality of a service.
A Market Overview on PEVQ embedding products reflects the application space for test tools in the life cycle of NGN's, while extending from pre-deployment feature testing for the lab, over load testing and test tools for installation and network optimization to IPTV test and monitoring equipment.
For the online version of the PEVQ Market Overview please go directly to
[www.PEVQ.org]
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