OPTICOM PESQ - DATASHEET 05-11-14 User manual

Key Features:
• Perceptual analysis of
degradations in voice sig-
nals
• Well established, repeat-
able results
• Output score correlates
very well with subjective
MOS
• Automatic time alignment
capability
• Available as DLL/Library
and Source
OPTICOM Product Line:
Voice/Audio Quality
PESQ ITU-T P.862
3SQM ITU-T P.563
PSQM ITU-T P.861
ECHO
PEAQ ITU-T BS.1387
Video Quality
PEVQ
Network Quality
VQmon
Voice
Quality Testing
PESQ – Perceptual Evaluation
of Speech Quality
OPTICOM’s PESQ (Perceptual Evaluation of
Speech Quality) provides accurate and repeat-
able estimates of speech quality degradation
occurring through e.g. a telephony network. It
compares the audio signal input to a network
with the corresponding (degraded) audio signal
output from the network. P.862 is based on the
earlier P.861 (PSQM) technology developed by
KPN Research extended to include a time align-
ment model.
Being already widely used in active testing in
both lab environments and in network test
equipment, OPTICOM's PESQ has achieved a
great reputation for its ease of use and its relia-
bility of its results while lowering the costs for
the measurements.
OPTICOM's PESQ is fully compliant to ITU-T
P.862.x covering the applicability to narrow
band as well as wide band audio signals.
OPTICOM who is the leading provider of signal
based perceptual measurement technologies
offers algorithms for voice, audio and video
quality measurements.
The degraded signal and the reference signal
are individually level aligned and filtered with
the transfer characteristics of a receiving device
(handset). Basically two different filter functions
– a narrow band (IRS) filter and a wide band fil-
ter – are available and may be chosen depend-
ing on the preferred application. After that the
two signals are time aligned in order to com-
pensate for small time shifts that can occur in
e.g. Voice over IP networks due to delay and jit-
ter changes and coding.
In order to account for the distortions that are
actually perceived by a human listener the
model transforms the two aligned and filtered
signals from the time-amplitude domain into a
frequency-loudness domain (auditory transform).
By subtracting the two signal representations
an estimate of the audible differences is
derived. The audible differences are accumulat-
ed over time while they are weighted different-
ly depending on whether a distortion was
added to the signal or if parts of the signal
were missing after the transmission (cognitive
model).
Finally after the analysis a single Mean Opinion
Score (MOS) is generated. The MOS is common-
ly used to describe the voice quality on a scale
from 1 (bad quality) to 5 (excellent quality).
Principle
PEVQ™, 3SQM™ and the OPTICOM logo are registered trademarks of OPTICOM GmbH; the ‘single-sided speech quality measure’ and
‘the perceptual quality experts’ are trademarks of OPTICOM GmbH. This information may be subject to change.
All brand and product names are trademarks and/or registered trademarks of their respective owners.
All rights reserved. Copyright © 2005 OPTICOM GmbH – www.opticom.de
Reference
signal
Level
align
Input
filter
Time
align and
equalise
Auditory
transform
Disturbance
processing
Auditory
transform
Cognitive
modelling
Identify bad
intervals
Level
align
Input
filter
System
under test
Degraded
signal
Re-align bad intervals
Prediction
of perceived
speech
quality

PEVQ™, 3SQM™ and the OPTICOM logo are registered trademarks of OPTICOM GmbH; the ‘single-sided speech quality measure’ and
‘the perceptual quality experts’ are trademarks of OPTICOM GmbH. This information may be subject to change.
All brand and product names are trademarks and/or registered trademarks of their respective owners.
All rights reserved. Copyright © 2005 OPTICOM GmbH – www.opticom.de
About OPTICOM
With PSQM, PESQ and PEAQ,
OPTICOM GmbH, the pioneer
in perceptual quality testing
has been providing three
international world-class
standards for voice and audio
quality measurement since
its foundation in 1995. With
their new single-sided
speech quality measure
3SQM™, a joint development
with partners, the perceptual
experts from Germany now
presented their fourth ITU
standard. At its 10th anniver-
sary, the presentation of the
new PEVQ™ video measure
leverages the company’s
huge experience towards the
multimedia testing domain.
Recognized an industry refer-
ence, OPTICOM’s OPERA
voice/audio quality test tools
are available to users world
wide. And while specialized
on OEM customers in particu-
lar, the directory of OEM
licensees today reads like the
‘Who-is-Who’ of the
Telecoms industry. OPTICOM
is a privately held company
located in Erlangen, Germany.
Sales Contacts:
OPTICOM GmbH
Nägelsbachstraße 38
91052 Erlangen, GERMANY
Phone: [phone]
Fax: [phone]
[email protected]
www.opticom.de
North America:
Telchemy Inc.
Phone [phone]
JDSU - Acterna U.S.
Phone [phone]
Europe, Latin America,
Middle East & Africa,
Asia Pacific, CIS Countries:
JDSU - Acterna
Germany GmbH
Phone: [phone]
Through our distributor net-
work, we are represented in
more than 80 countries. To find
your local sales office, please
contact [email protected]
Specifications
Functionality
• ITU-T P.862.x Perceptual Evaluation of
Speech Quality, with mapping to MOS scale
• Narrowband and Wideband operation
Input
• 16 bit linear audio sampled at 8kHz and
16kHz
• Input voice files 6 to 20 seconds in length
Output
• VAD measurements (front end clipping, hold
over time)
• Drop out measurement
• Delay measurement and statistics (min, max,
average, delay vs. time, histogram)
• MOS vs. time
• MOS for speech and silent parts separately
• Attenuation
• Speech level (total, active speech, silence,
reference, test separately)
• Loudness (reference, test)
• AGC measurement
• R Factor (LQ)
Complexity
• P.862 is processed in about 10-20 times
faster than real-time on a Pentium III
733MHz (44-125MFLOPs)
• Data memory: 5.2MB for file pair with 8s
length
• Code memory: App. 200-400kb (depending
on used features and optimizations)
• Floating point library required
Platforms
• Windows
• Linux
• Solaris
PESQ – Perceptual Evaluation of Speech Quality
One of the major advantages of PESQ over
other measurement approaches is that it does
not need to make any assumptions on the net-
work under test or the distortion types that may
occur in a specific telephony test scenario. The
only prerequisite employed within the model is
the scientific knowledge on how human speech
is produced and how humans perceive it.
PESQ already includes the effects of both pack-
et level impairments (loss, jitter) and signal
related impairments such as noise, clipping and
distortions caused by coding processes. The
impairment model, based on this knowledge is
as generic as it can be and therefore independ-
ent from current and future telephony applica-
tions and networks.