Analysis of video quality losses in the homogenous HEVC video transcoding

The paper presents quantitative analysis of the video quality losses in the homogenous HEVC video transcoder. With the use of HM15.0 reference software and a set of test video sequences, cascaded pixel domain video transcoder (CPDT) concept has been used to gather all the necessary data needed for the analysis. This experiment was done for wide range of source and target bitrates. The essential result of the work is extensive evaluation of CPDT, commonly used as a reference in works on effective video transcoding. Until now no such extensively performed study have been made available in the literature. Quality degradation between transcoded video and the video that would be result of direct compression of the original video at the same bitrate as the transcoded one have been reported. The dependency between quality degradation caused by transcoding and the bitrate changes of the transcoded data stream are clearly presented on graphs

High-Fidelity Generative Image Compression

We extensively study how to combine Generative Adversarial Networks and learned compression to obtain a state-of-the-art generative lossy compression system. In particular, we investigate normalization layers, generator and discriminator architectures, training strategies, as well as perceptual losses. In contrast to previous work, i) we obtain visually pleasing reconstructions that are perceptually similar to the input, ii) we operate in a broad range of bitrates, and iii) our approach can be applied to high-resolution images. We bridge the gap between rate-distortion-perception theory and practice by evaluating our approach both quantitatively with various perceptual metrics and a user study. The study shows that our method is preferred to previous approaches even if they use more than 2x the bitrate.Comment: Project page: https://hific.github.i