Constant quality rate control for video encoding based on activity segmentation

Abstract

An enhanced, off-line, segment-based rate control approach is proposed for controlling the distortion variation across successive segments of a video sequence when encoding with single-layer (MPEG-4 Baseline, MPEG-4 AVC) and wavelet video codecs. Consistent quality is achieved by a time-efficient, predictive ratedistortion modeling per segment. The individual segments are either shots or sub-shots, that are defined based on shot segmentation and activity analysis techniques. The rate control method solves the quality stability problem of state-of-the-art codecs, especially for less mature rate control modules (such as present in MPEG-4 AVC). The processing overhead compared to classical two-pass VBR encoding is limited while the distortion variation is significantly reduced. 1