5
PEVQ™ Analyzer
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 percep-
tually motivated parameters.
Distortion indicators
For a more detailed analysis the percep-
tual level of distortion in the luminance,
chrominance and temporal domain are
provided.
Delay
The min, max and mean delay of each
frame of the test signal related to the
reference signal, as well as delay vs.
time.
Brightness
The brightness of the reference and
degraded signal.
Contrast
The contrast of the distorted and the ref-
erence sequence.
PSNR
To allow for a coarse analysis of distor-
tions in different domains the PSNR is
provided for the Y, Cb and Cr components
separately.
Jerkiness
describes the smoothness of a video
playback which is often impaired by
down-sampling, coding processes and
perturbed transmissions.
Blur
is a distortion characterized by reduced
sharpness of contour edges and spatial
detail.
Blockiness
is often the result of a low bit rate cod-
ing that uses a block matching algorithm
for the motion estimation and a coarse
quantization for the image blocks.
Frame Skips and Freezes
are temporal artefacts occurring in video
transmissions caused by e.g. overloaded
networks.
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 quan-
tifying the severeness of such a process.
Temporal Activity and Spatial
Complexity
Temporal activity and spatial complexity
indicators quantify the amount of activi-
ty/movement and spatial detail in the
video content. These indicators are
derived from ITU-T recommendation
P.910.
Output
New in PEXQ: The composite result view
for audio-visual quality analysis reporting
the video MOS (PEVQ) (upper frame) and
the audio MOS (PESQ) (middle frame).
The combination of perceptual video and
audio quality measures allows for
detailed lip-sync analysis based on time-
variant delay analysis (lower frame).
