An Efficient Region-of-Interest (ROI) based Scalable Framework for Free Viewpoint Video Application

Background and Objectives: From the multiview recorded video, free viewpoint video provides flexible viewpoint navigation. Thus, a lot of views need to be sent to the receivers in an encoded format. The scalable nature of the coded bitstream is one method of lowering the volume of data. However, adhering to the limitations of the free viewpoint application heavily relies on the kind of scalable modality chosen. The perceptual quality of the received sequences and the efficiency of the compression technique are significantly impacted by the scalable modality that was chosen. Methods: In order to address the primary issues with free-viewpoint video, such as high bandwidth requirements and computational complexity, this paper suggests a scalable framework. The two components of the suggested framework are as follows: 1) introducing appropriate scalable modality and data assignment to the base and enhancement layers; and 2) bit budget allocation to the base and enhancement layers using a rate control algorithm. In our novel scalable modality, termed Tile-based scalability, the idea of Region of Interest (ROI) is employed, and the region of interest is extracted using the tile coding concept first presented in the MV-HEVC. Results: When compared to the state-of-the-art techniques, our approach s computational complexity can be reduced by an average of 44% thanks to the concept of tile-coding with parallel processing capabilities. Furthermore, in comparison to standard MV-HEVC, our suggested rate control achieves an average 17.7 reduction in bandwidth and 1.2 improvement in video quality in the Bjøntegaard-Bitrate and Bjøntegaard-PSNR scales. Conclusion: Using new tile-based scalability, a novel scalable framework for free-viewpoint video applications is proposed. It assigns appropriate regions to the base and enhancement layers based on the unique features of free viewpoint scalability. Next, a rate control strategy is put forth to allocate a suitable bitrate to both the base and enhancement layers. According to experimental results, the suggested method can achieve a good coding efficiency with significantly less computational complexity than state-of-the-art techniques that used the λ domain rate control method.