No abstract

In video coding, it is commonly accepted that the encoding parameters such as the quantization step-size have an influence on the perceived quality. It is also sometimes accepted that using given encoding parameters, the perceived quality does not change significantly according to the encoded source content. In this paper, we present the outcomes of two video subjective quality assessment experiments in the context of Scalable Video Coding. We encoded a large set of video sequences under a group of constant quality scenarios based on two spatially scalable layers. One first experiment explores of the relation between a wide range of quantization parameters for each layer and the perceived quality, while the second experiment uses a subset of the encoding scenarios on a large number of video sequences. The two experiments are aligned on a common scale using a set of shared processed video sequences, resulting in a database containing the subjective scores for 60 different sources combined with 20 SVC scenarios. We propose a detailed analysis of the experimental results of the two experiments, bringing a clear insight of the relation between the encoding parameters combination of the scalable layers and the perceived quality, as well as spreading light on the differences in terms of quality depending on the encoded source content. As an endeavour to analyse these differences, we propose a classification of the sources with regards to their relative behaviour when compared to the average of other source contents. We use this classification to identify potential factors to explain the differences between source contents.

No abstract

No abstract

No abstract