An Optimized Temporal Filter Implementation for Practical Applications

VVenC, an open and optimized VVC encoder implementation, employs a temporal filter from the literature as a pre-processing step. The filter effectively reduces camera noise from input video, thereby increasing the encoding gain for lossy encoding, at a price of fairly high complexity, further increased by the necessity of consistent application to many pictures. The filter represents one of the most runtime consuming processing steps for the fastest operating points of VVenC. In this paper, steps are described to reduce the complexity of the temporal filtering in VVenC, to allow its application with low-complexity presets. Overall, the filter runtime is reduced by a factor of around 17 compared to the state of the art, while slightly improving its performance. An additional 4 times speedup is achieved using vectorized implementation. In the proposed version, for the VVenC preset faster, the filter provides 7.36% BD-rate gain at only 2% runtime overhead.