Constant quality rate-control for video encoding based on activity segmentation

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 rate-distortion modeling per segment. The individual segments are either shots or sub-shots, that are defined based oil 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.