PEVQ
™
Analyzer
Perceptual Video Quality-of-Experience Measurement
OPTICOM Product Line:
Video
Quality
Testing
V
oice
Quality
Testing
A
udio
Quality
Testing
Data
Quality
Testing
The new PEVQ Analyzer evaluates the quality of
multimedia (QCIF, CIF, VGA), SD and HD video formats based on perceptual video quality-ofexperience measurement, reliably and objectively.
The system allows for synchronous SD and HD
play-out and recording over a range of interfaces
(HD-SDI, DVI) and comes with a high-performance, front accessible array of hard disk drives.
Perceptual Evaluation of Video Quality (PEVQ) is
an accurate, reliable and fast video quality measurement technology, developed by OPTICOM. It
provides mean opinion score (MOS) analysis of
the video quality degradation occurring through a
network, e.g. in mobile and IP-based networks.
PEVQ can be ideally applied to test video telephony, video conferencing, video streaming, and IPTV
applications.
PEVQ is a full-reference, end-to-end measurement
based on signal analysis: The degraded video signal output from a network is analyzed by comparison to the undistorted original reference video
signal on a perceptual basis. Based on the
approach to model the human visual system,
PEVQ can detect anomalies in the video signal and
quantify them by a multitude of key performance
indicators (KPIs). With PEVQ one can analyze the
video quality based on a human visual model, thus
representing the true image quality as perceived
by subjects, for example paying subscribers. Its
value proposition is obvious: equipment manufacturers, network operators and service providers
can analyze QoE issues and optimize next generation networks and thus avoid customer's dissatisfaction, which otherwise might lead to complains
or churn.
OPTICOM, the leading provider of signal based
perceptual measurement technology for voice,
audio and video, offers its new easy to use PEVQ
testing technology in combination with its proven
audio quality analysis techniques PESQ
(Perceptual Evaluation of Speech Quality) and
PEAQ (Perceptual Evaluation of Audio Quality).
The combination with these state-of-the-art test
algorithms allows for audio-visual quality analysis
and thus provides useful means for lip-sync artefact measurement.
Users can choose among the PEXQ software suite
for Windows™ and the PEVQ Analyzer. PEVQ is
also available as an OEM solution and has been
adopted by a range of leading industry partners
(see www.pevq.org for further information on
third parties' product availability).
PEVQ is based on the earlier PVQM technology
developed by KPN Research and new developments of OPTICOM. The PEVQ analyzer is produced in cooperation with DVC Germany
(www.digitalvideo.de).
PEVQ has been verified by the Video Quality
Experts Group in 2008 and is going to be proposed
for International Standardization.
Key Features:
• Accurate, reliable and fast
objective analysis of perceived video quality
• Full reference based endto-end quality analysis
• Outputs MOS score
that correlates well
with subjective MOS
• Additional KPIs for
detailed analysis
• Measurement of multimedia (QCIF, CIF, VGA), SD
and HD video quality
• Applications: IPTV, streaming video, 3G, video
telephony
• Performance verified and
recommended for standardization by the Video
Quality Experts Group
(www.vqeg.org) 2008
PEXQ™, 3SQM™, PEAQ™, PEVQ™, PEDQ™ andthe OPTICOMlogo are registered trademarks of OPTICOM GmbH; PESQ™ is aregistered trademarkof OPTICOM
GmbH and Psytechnics Ltd.; the 'Single-sidedSpeech QualityMeasure' and 'The Perceptual Quality Experts' are trademarks of OPTICOMGmbH.
This information may be subject tochange. Allother brand and product names are trademarks and/or registered trademarks
of their respective owners. All rightsreserved. Copyright© 2008 OPTICOM GmbH - www.opticom.de
Voice Quality Testing
PSQM ITU-T P.861
PESQ ITU-T P.862
3SQM ITU-T P.563
ECHO
Audio Quality Testing
PEAQ ITU-T BS.1387
Video Quality Testing
PEVQ
Network Quality Testing
VQmon
N
EW:
VQEG
appr
oved for
standar
di
zat
ion
The PEXQ split screen feature of the viewer
window allows for a 1:1 comparison of the
degraded (test) video with the original reference by horizontal and/or vertical split of
the overlay. This display feature is ideally
suited for codec developers and cause
analysis, as sliding through the image may
visualize even slight deviations from the
original (left half of the image). In this HD
IPTV example, bit errors were inserted during the IP transport (visible in the right half
of the image).
PEXQ™, PEAQ™, PEVQ™, PEDQ™, 3SQM™ andthe OPTICOMlogo are registered trademarks of OPTICOM GmbH; PESQ™ is aregistered trademarkof OPTICOM GmbH and
Psytechnics Ltd.; the ‘Single-sided Speech QualityMeasure’ and‘The Perceptual Quality Experts’ are trademarks of OPTICOM GmbH. Thisinformation maybe subject to
change. All other brand and productnames aretrademarks and/or registered trademarks of their respective owners.
All rights reserved. Copyright © 2008OPTICOM GmbH– www.opticom.de
2 PEVQ™ Analyzer
Comfortable Graphical User Interface
Split View Overlay
2
1
3
The PEVQ Analyzer desktop combinesPEXQ (1), OPTICOM'sunified graphical user interface
providing a Quad-KPI set for voice, audio, video and data analysis, and QuickClip (2) (powered by Drastic Technologies) for comfortable play-out and record. The PEXQ view window
(3) allows for visual frame-by-frame overlay comparison of original, degraded (test) signal
and PEVQ internal error patterns.
3PEVQ™ Analyzer
Principle
Human Visual Model View
The internal PEVQ views expose an insight
to the human visual model at work. From
left to right:
1) Frame of the original reference
sequence
2) Corresponding frame of the degraded
(test) signal
3) Degraded signal after temporal and
spatial alignment
4) Difference error pattern according to
PEVQ's human visual model, this perceptible error forms the basis for the
MOS calculation.
In the example shown, it can be noted that
the degraded signal contained a lower
frame rate than the original, which leads
to temporal and spatial alignment artefacts that may contribute to the error pattern for the particular frame analyzed.
(This example was pictured intentionally
for illustration purposes).
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 for high definition video.
OPTICOM’s PEVQ is one of the two topranked models in the 2008 Video Quality
Experts Group (VQEG) multimedia evaluation and approved for standardization.
Temporal indicators
T
emporal
and spatial
a
lignment
D
istortion
classifi-
c
ation
Reference Signal
Impaired Signal
Y
Cr
Cb
Perceptual
difference
(Y, Cr, Cb)
PEVQ Score
Indicators
f
or cause
analysis
}
time
time
Distortion
indicator
integration
PEVQ is a full reference, intrusive measurement algorithm for video quality. Its
basic structure is shown in the figure below.
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