Analysis of Video Quality Losses in Homogeneous HEVC Video Transcoding

Tomasz Grajek,Krzysztof Wegner,Jakub Stankowski,Damian Karwowski,Krzysztof Klimaszewski,Olgierd Stankiewicz

doi:10.1109/access.2019.2928423

Tomasz Grajek, Krzysztof Wegner + Show 4 more

Open Access

https://doi.org/10.1109/access.2019.2928423

Copy DOI

Abstract

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

Highlights

Techniques of hybrid compression of digital video are the most common methods of video transmission used in contemporary IT networks
The state-of-the-art in the field of video compression is the High Efficiency Video Coding (HEVC) technology [6] that has been jointly developed by ISO/IEC and ITU-T and published in 2013 simultaneously as an international standard of ISO/IEC MPEG-H part 2 and recommendation ITU-T H.265 [5]
VIDEO QUALITY IN HOMOGENEOUS HEVC TRANSCODING - FURTHER CONSIDERATIONS The results presented in the previous section clearly show that when transcoding a video, the mutual relationship of the quantization parameters of source bitstream QPS and target bitstream QPT determines directly how big the loss of quality of a signal will be

Summary

Introduction

Techniques of hybrid compression of digital video are the most common methods of video transmission used in contemporary IT networks. Used and extremely successful Advance Video Coding (AVC) technology [4], [7] Comparing these two techniques, HEVC allows up to a 2-fold reduction in the size of the encoded images without compromising the quality of video [8], and, more importantly, it supports the compression of ultra-high definition video, which is believed to be the future of video systems. HEVC allows up to a 2-fold reduction in the size of the encoded images without compromising the quality of video [8], and, more importantly, it supports the compression of ultra-high definition video, which is believed to be the future of video systems For this reason, it is highly expected that within the few years, the new HEVC technique will replace the currently used AVC technology in most fields

Objectives

Findings

Conclusion