GOP Structure-Independent Quantization Parameter Cascading in Video Coding

• Main Authors: Yiwen Xu, Shiqi Yi, Liqun Lin, Weiling Chen, Tiesong Zhao
• Format: Article
• Language: English
• Published: IEEE 2019-01-01
• Series: IEEE Access
• Subjects: Video coding; quantization parameter (Qp); rate-distortion (RD); high efficiency video coding (H.265/HEVC)
• Online Access: https://ieeexplore.ieee.org/document/8735843/

The popular lossy coding standards set unequal quantization parameter (Qp) values to its successive frames or slices aimed at minimizing its encoder distortion subject to a bitrate constraint. Nowadays, this Qp cascading (QPC) strategy is normally achieved by the derivation of an optimization problem with regard to the group-of-picture (GOP) structure of successive frames. In this paper, we propose to extract coding unit (CU)-level predicting information and project them to frame-level dependency with real-time neural networks. Thus, we successfully estimate and update the frame-level dependency in a GOP without prior knowledge to the GOP-level prediction structure. Finally, the dependency is utilized in adaptive QPC for diverse GOP structures. The experimental results on high efficiency video coding (H.265/HEVC) demonstrate the effectiveness of our proposed framework, which achieves adaptive QPC for both random access (RA) and low delay (LD) structures with superior rate-distortion (RD) performances.