Hybrid context modeling and wavelet transform for region of interest detection and rate control based on VP9 video codec

Abstract

SummaryRegion of interest detection is a useful technique in video encoding. This work presents a model to distinguish region of interest area based on VP9 video codec. The model contains high motion, contrast, color sensitive areas which fits for human visual system. A hybrid detection algorithm, including Wavelet Transform and Context Modeling method, is proposed. The algorithm approximately reveals ROI details for the sake of pursuing computing time. In ROI‐based encoding, adjusting encoding parameters for region of interest (ROI) during the encoding procedure can bring turbulence in bits output, a rate control model is established in this work. We also design a rate control mechanism for ROI encoding mode both in CBR and VBR to maintain the output bit rate stable. The encoding parameter are set specifically in different ROI areas to improve both visual effects and PSNR. The proposed detection method and rate control mechanism work well in VP9 codec and contribute saving bits according to experimental results.