Effect of content characteristics on quality of experience of adaptive streaming

The growing popularity of adaptive streaming-based video delivery nowadays has raised the interest about the user's perception when experiencing quality adaptation. The impact of the video content characteristics on user's perceptual quality has already become evident. The aim of this study is to investigate the influence of this factor on the quality of experience of adaptive streaming scenarios. Our results show that the perceptual quality of adaptation strategies applied on videos with high spatial and low temporal amount of activity is significantly lower compared to the other content types

A New Low Complex Reference Free Video Quality Predictor

In many applications and environments for mobile communication there is a need for reference free perceptual quality measurements. In this paper a method for prediction of a number of quality metrics is proposed, where the input to the prediction is readily available parameters at the receiver side of a communications channel. Since the parameters are extracted from the coded video bit stream the model can be used in user scenarios where it is normally difficult to estimate the quality due to the reference not being available, as in streaming video and mobile TV applications. The predictor turns out to give good results for both the PSNR and the PEVQ metrics

En ny prediktor för videokvalitet baserad på avkodarens parameterextrahering

In the mobile communication area there is a demand for reference free perceptual quality measurements in video applications. In addition low complexity measurements are required. This paper proposes a method for prediction of a number of well known quality metrics, where the inputs to the predictors are readily available parameters at the decoder side of the communication channel. After an investigation of the dependencies between these parameters and between each parameter and the quality metrics, a set of parameters is chosen for the predictor. This predictor shows good results, especially for the PSN

En ny prediktor för videokvalitet baserad på avkodarens parameterextrahering

In the mobile communication area there is a demand for reference free perceptual quality measurements in video applications. In addition low complexity measurements are required. This paper proposes a method for prediction of a number of well known quality metrics, where the inputs to the predictors are readily available parameters at the decoder side of the communication channel. After an investigation of the dependencies between these parameters and between each parameter and the quality metrics, a set of parameters is chosen for the predictor. This predictor shows good results, especially for the PSN

A robust method for estimating synchronization and delay of audio and video for communication services

One of the main contributions to the quality of experience in streaming services or in two-way communication of audio and video applications is synchronization. This has been shown in several studies and experiments but methods to measure synchronization are less frequent, especially for situations without internal access to the application and independent of platform and device. In this paper we present a method for measuring synchronization skewness as well as delay for audio and video. The solution incorporates audio and video reference streams, where audio and video frames are marked with frame numbers which are decoded on the receiver side to enable calculation of synchronization and delay. The method has been verified in a two-way communication application in a transparent network with and without inserting known delays, as well as in a network with 5 and 10 % packet loss levels. The method can be used for both streaming and two-way communication services, both with and without access to the internal structures, and enables measurements of applications running on e.g. smartphones, tablets, and laptops under various conditions

Analysis of the impact of temporal, spatial, and quantization variations on perceptual video quality

The growing consumer interest in video communication has increased the users' awareness in the visual quality of the delivered media. This in turn increases, at the service provider end, the need for intelligent methodologies of optimal techniques for adapting to varying network conditions. Recent studies show that constraints on the bandwidth of transmission media should not always be translated to an increase in compression ratio to lower the bitrate of the video. Instead, a suitable option for adaptive streaming is to scale down the video temporally or spatially before encoding to maintain a desirable level of perceptual quality, while the viewing resolution is constant. Most of the existing studies to examine these scenarios are either limited to low resolution videos or lack in provisioning of subjective assessment of quality. We present here the results of our campaign of subjective quality assessment experiments done on a range of spatial and temporal resolutions, up to VGA and 30 frames per second respectively, under a number of bitrate conditions. The analysis shows, among other things, that keeping the spatial resolution is perceptually preferred among the three parameters that have impact on the video quality, even in the case with high temporal activity

A New Video Quality Predictor Based on Decoder Parameter Extraction

In the mobile communication area there is a demand for reference free perceptual quality measurements in video applications. In addition low complexity measurements are required. This paper proposes a method for prediction of a number of well known quality metrics, where the inputs to the predictors are readily available parameters at the decoder side of the communication channel. After an investigation of the dependencies between these parameters and between each parameter and the quality metrics, a set of parameters is chosen for the predictor. This predictor shows good results, especially for the PSN