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C H A P T E R
5 :
Sound
Recorder
Figure 5.2: Kinds of signal sources for the PEAQ measurement
5.4 Fundamentals of the PEAQ
Measurement Algorithm
As mentioned in paragraph 2.3, the ITU-R recommended an objective,
perception based model to evaluate the quality of wide band audio codecs.
This model was recommended as a measure for the perceived audio quality
("
PEAQ
") under recommendation BS.1387. There are two versions of
"Basic" version, featuring a low complexity approach, and an "Advanced"
version for higher accuracy at the trade off of higher complexity. The following
paragraphs provide some background information about
understanding of measurement results.
5.4.1 Background of the PEAQ (ITU-R BS.1387) Development
Not all members of the ITU task group TG10/4, which developed the new
recommendation for the measurement of the perceived audio quality, were
designing algorithms. On the contrary, most members represented potential
users of such a system. The development therefore was influenced by the
feedback of the users group with respect to their requirements. This feedback
resulted in a list of applications, which the new method would have to face in a
typical broadcast environment.
Basic and Advanced Version
By comparing both, the list of applications and the state-of-the-art technology, it
became clear that not all requirements could be met by a single version of the
algorithm. Most notably, a discrepancy exists between the demand for a real
time measurement tool, highest possible accuracy and reasonable hardware
efforts for an implementation. As a result, it was decided to develop a new
method consisting of two versions. The "
computational efficiency and realtime performance, while the "
version yields for highest possible accuracy.
The following sections are intended to present a brief overview of the
fundamental principles involved. For further details about the algorithm, please
refer to the mentioned references.
5.4.2 Common Elements of PEAQ Basic and PEAQ Advanced
The structure of both versions is very similar, and fits exactly into the algorithm
layout described in Chapter 4.1. The major difference between the Basic and
W I D E
B A N D
A U D I O
Sources:
Files
(always)
Audio
(audio board version)
87
Q U A L I T Y
T E S T I N G
Offline
PEAQ
Online
PEAQ
" version was defined for
Basic
PEAQ
, a
to improve the
Advanced
"
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