Video Quality Model for Variable Frame Delay (VQM_VFD)

Time varying delays of the output (or processed) video frames with respect to the input (i.e., the original or reference) video frames present significant challenges for Full Reference (FR) video quality measurement systems. Time alignment errors between the output video sequence and the input video sequence can produce measurement errors that greatly exceed the perceptual impact of these time varying video delays. This document proposes a new video quality model (VQM) that properly accounts for the perceptual impact of variable frame delay (VFD). This new model, called VQM_VFD, also uses perceptual features extracted from spatial-temporal (ST) blocks of a fixed angular extent. This enables VQM_VFD to track subjective quality over a wide range of viewing distances and image sizes. VQM_VFD uses a neural network that achieves 0.9 correlation to subjective quality for subjective datasets at image sizes from Quarter Common Intermediate Format (QCIF) to High Definition TV (HDTV).