Circular Rectifiction of 3D Video and Efficient Modification of 3D-HEVC

Video acquired from multiple cameras located along a line is often rectified to video virtually obtained from cameras with ideally parallel optical axes collocated on a single plane and principal points on a line. Such an approach simplifies video processing including depth estimation and compression. Nowadays, for many application video, like virtual reality or virtual navigation, the content is often acquired by cameras located nearly on a circle or on a part of that. Therefore, we introduce new operation of circular rectification that results in multiview video virtually obtained from cameras located on an ideal arc and with optical axes that are collocated on a single plane and they intersect in a single point. For the circularly rectified video, depth estimation and compression are simplified. The standard 3DHEVC codec was designed for rectified video and its efficiency is limited for video acquired from cameras located on an arc. Therefore, we developed a 3-D HEVC codec modified in order to compress efficiently circularly rectified video. The experiments demonstrate its better performance than for the standard 3D-HEVC codec.

Multiview Video Compression Using Advanced HEVC Screen Content Coding

The paper presents a new approach to multiview video coding using Screen Content Coding. It is assumed that for a time instant the frames corresponding to all views are packed into a single frame, i.e. the frame-compatible approach to multiview coding is applied. For such coding scenario, the paper demonstrates that Screen Content Coding can be efficiently used for multiview video coding. Two approaches are considered: the first using standard HEVC Screen Content Coding, and the second using Advanced Screen Content Coding. The latter is the original proposal of the authors that exploits quarter-pel motion vectors and other nonstandard extensions of HEVC Screen Content Coding. The experimental results demonstrate that multiview video coding even using standard HEVC Screen Content Coding is much more efficient than simulcast HEVC coding. The proposed Advanced Screen Content Coding provides virtually the same coding efficiency as MV-HEVC, which is the state-of-the-art multiview video compression technique. The authors suggest that Advanced Screen Content Coding can be efficiently used within the new Versatile Video Coding (VVC) technology. Nevertheless a reference multiview extension of VVC does not exist yet, therefore, for VVC-based coding, the experimental comparisons are left for future work.