Instruction Manual

78
Glossary
Perceptual Quality Metrics
Metric Description
MOS-V Video MOS, a 1-5 score that considers the effect of the video codec,
frame rate, packet loss distribution and GoP structure on viewing quality
MOS-A1 and MOS-A2 for 2 codecs that
are present in some streams
Audio MOS, a 1-5 score that considers the effect of the audio codec, bit
rate, sample rate and packet loss on viewing quality
MOS-A1V Audio-Video MOS – a 1-5 score that considers the effect of picture &
audio quality and audio-video synchronization on overall user experience
Video Service Transmission Quality
(VSTQ)
Transmission quality, a 0-50 codec independent score measuring the
ability of the IPTV network to carry reliable video
Video Service Picture Quality (VSPQ) Picture quality, a 0-50 score that considers the effect of the video codec,
frame rate, packet loss distribution and GoP structure
Gap VSPQ Picture quality during “good” periods when little or no degradation is
occurring
Burst VSPQ Picture quality during “bad” periods when significant degradation is
occurring
Video Service Audio Quality for 2
codecs (VSA1Q and VSA2Q)
Audio quality, a 0-50 score that considers the effect of the audio codec,
bit rate, sample rate and packet loss on viewing quality
Video Service Multimedia Quality
(VSMQ)
Multimedia (Audio-Video) quality, a 0-50 score that considers the effect
of picture & audio quality and audio-video synchronization on overall
user experience
Estimated PSNR (EPSNR) Estimated Peak Signal to Noise Ratio (PSNR) expressed in dB. This is an
estimate of the distortion that has occurred between the source video
stream and the output video stream.
Degradation Factors Percentage degradation in quality due to (each of) Loss, Discard, Codec
type, Audio-Video Sync, Delay and Recency.