Pablo Piñol

A Study of Objective Quality Assessment Metrics for Video Codec Design and Evaluation

When comparing the performance of different video coding approaches, improvements or new codec designs, one of the most important performance metrics is the rate/distortion (R/D), where distortion use to be measured in terms of PSNR (peak signal-to-noise ratio) values. However, it is well known that this metric not always capture the distortion perceived by the human being. So, a lot efforts were performed to define an objective video quality metric that is able to measure video quality distortion close to the one perceived for the destination user. In this work, we perform a study of different available objective quality metrics in order to evaluate their behaviour, taking as reference the classical PSNR metric. Our purpose is to find, if any, a video quality metric that is able to substitute PSNR for video quality assessment and determine a more accurate R/D performance metric when designing and evaluating video codec proposals

Quality assessment metrics vs. PSNR under packet lossscenarios in manet wireless networks

It is well known that PSNR does not always rank quality of an image or video sequence in the same way that a human being. There are many other factors considered by the human visual system and the brain. So, a lot of efforts were required to find an objective video quality metric that is able to measure the quality distortion similarly to the one perceived by the destination user. We analyze the behaviour of some of the most relevant objective quality metrics when they are applied to video compressed by a H264/AVC codec at different bit-rates and with error resilience options enabled. Video data is transmitted in a wireless MANET environment and packet losses are modelled for different scenarios including variable congestion and mobility states. We take as reference the PSNR metric and try to find out if there is a more accurate metric in terms of human quality perception that could substitute PSNR in the performance evaluation of different coding proposals under packet loss scenarios.

Slice-based parallel approach for HEVC encoder

The high efficiency video coding (HEVC) is the newest video coding standard from the ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group, which significantly increases the computing demands to encode video to reach the limits on compression efficiency. Our interest is centered on applying parallel processing techniques to HEVC encoder to significantly reduce the computational time without disturbing the coding performance behavior. We propose a parallelization approach to the HEVC encoder which is well suited to multicore architectures. Our proposal uses OpenMP programming paradigm working at slice parallelization level. We encode several slices of each frame at the same time using all available processing cores. The results show that speed-ups up to

Evaluating H.265 real-time video flooding quality in highway V2V environments

9.8

Parallel strategies analysis over the HEVC encoder

9.8 can be obtained for the All Intra mode and up to

Low bit-rate video coding with 3d lower trees (3D-LTW)

8.7