Perceptual Video Quality Metric Research Articles

Perceptual video quality metric for compression artefacts: from two‐dimensional to omnidirectional

In this study, the perceptual video quality (PVQ) for the vogue 360-degree video with compression artefacts viewed on the visual reality (VR) head-mounted display (HMD) is obtained for the first time by an elaborately designed subjective experiment. The characteristic of the PVQ of omnidirectional (360-degree) video on the VR HMD and PC monitor is then investigated. The PVQ on the HMD is found to be linearly related to the video coding quality (VCQ) on the PC monitor. A quality evaluation model is then proposed based on the mapping formula and a new assessment parameter, where the impact of the video resolution and display device is involved. In this way, the traditional video quality assessment metrics for two-dimensional video can be extended to assess the PVQ of the 360-degree video viewed on the HMD. At last, the video structural similarity metric is taken as an example to predict the input of the proposed model, i.e. the VCQ of the 360-degree video. Experimental results demonstrate that the proposed model can effectively and conveniently solve the challenge of PVQ assessment for the 360-degree video with compression distortions on the HMD.

A perception based bit allocation for 3DTV broadcasting

Perceptually adaptive bit allocation plays vital roles in efficient rate control to achieve rate distortion optimization in terms of perceptual video coding. This paper proposes a perceptually improved bit allocation scheme by employing a more accurate distortion model inspired by a state-of-the-art perceptual video quality metric. The contributions of this paper mainly involve the following three aspects. Firstly, a perceptual rate-distortion model is developed to shape the framework of perceptual video coding. Secondly, based on the characteristics of the model, an adaptively frame-level bit allocation scheme is proposed using the rate distortion optimization technology. Meanwhile, the status of the encoder buffer is also taken into account to avoid overflow or underflow. Finally, a macroblock-level quantization parameter adjustment is presented to improve perceptual video quality. Experimental results demonstrate that the whole proposed bit allocation scheme achieves better perceptual rate-distortion performance and guarantees the accuracy of rate control well.

Perceptual video quality assessment in H.264 video coding standard using objective modeling.

Since usage of digital video is wide spread nowadays, quality considerations have become essential, and industry demand for video quality measurement is rising. This proposal provides a method of perceptual quality assessment in H.264 standard encoder using objective modeling. For this purpose, quality impairments are calculated and a model is developed to compute the perceptual video quality metric based on no reference method. Because of the shuttle difference between the original video and the encoded video the quality of the encoded picture gets degraded, this quality difference is introduced by the encoding process like Intra and Inter prediction. The proposed model takes into account of the artifacts introduced by these spatial and temporal activities in the hybrid block based coding methods and an objective modeling of these artifacts into subjective quality estimation is proposed. The proposed model calculates the objective quality metric using subjective impairments; blockiness, blur and jerkiness compared to the existing bitrate only calculation defined in the ITU G 1070 model. The accuracy of the proposed perceptual video quality metrics is compared against popular full reference objective methods as defined by VQEG.

Interference Shaping for Improved Quality of Experience for Real-Time Video Streaming

The unpredictability of the wireless medium poses a major challenge to delivering a high quality of experience (QoE) for real-time video services. Bursty co-channel interference is a prominent cause of wireless throughput variability, which leads to video QoE degradation, even for a fixed average channel quality. In this paper, we propose and analyze a network-level resource management algorithm termed interference shaping to smooth out the throughput variations (and hence improve the QoE) of video users by decreasing the peak rate of co-channel best effort users. Wireless link capacity variations are mapped to the real-time video packet loss rate, and the interference shaping QoE gain for video users is quantified by benchmarking against a modified multi-scale structural similarity (H-MS-SSIM) index. H-MS-SSIM is an accurate perceptual video quality metric that incorporates the important hysteresis effect whereby the current QoE (which is subjective) may strongly depend on the recent past. The proposed technique increases mean QoE and reduces the QoE variability over time, with a net perceptual increase of about 2-3x in illustrative settings while incurring insignificant decrease in the QoE for co-channel best effort users. Interference shaping can be implemented in both unicast and multicast real-time video streaming with much higher potential gains for multicast.

VQeg validation and ITU standardization of objective perceptual video quality metrics [Standards in a Nutshell

For industry, the need to access accurate and reliable objective video metrics has become more pressing with the advent of new video applications and services such as mobile broadcasting, Internet video, and Internet Protocol television (IPTV). Industry-class objective quality- measurement models have a wide range of uses, including equipment testing (e.g., codec evaluation), transmission- planning and network-dimensioning tasks, head-end quality assurance, in- service network monitoring, and client-based quality measurement. The Video Quality Experts Group (VQEG) is the primary forum for validation testing of objective perceptual quality models. The work of VQEG has resulted in International Telecommunication Union (ITU) standardization of objective quality models designed for standard- definition television and for multimedia applications. This article reviews VQEG's work, paying particular attention to the group's approach to validation testing.