VIDEO SEQUENCES

Streaming of high-quality video contents as part of multimedia communication, has become essential nowadays. Video delivered over the network suffers from different kind of impairments, which degrades its quality. Such network impairments effect differs among different types of codec used. This paper present the effects of network degradation factors such as packet loss and jitter over H.264 and H.265 encoded video sequences. In addition to the codec used, we also focused on the different level of temporal and spatial aspect within the videos. Among different basic test methods, double stimulus impairments scale was used to complete the experiment as subjective measures of assessment metric from user's perspective.The result illustrates that differently encoded video sequences react differently to the network impairments and are very sensitive to a transmission error. Similarly, it also shows that user's experience is affected according to the motion level of video.

In this paper, we present a study on VDF and VMF filters in terms of efficiency for filtering impulsive noise in video sequences. These nonlinear filters are used in improving the quality of image/video and especially the noise attenuation and detail preservation of the image/video. We evaluate the performance of the two filters by using three CIF (Common Intermediate Format) sequences (Akiyo, Foreman and Tb420). We used for the evaluation of filter performance three quality assessment criteria (PSNR, SSIM and DVQ). For all quality metrics (PSNR, SSIM, DVQ), we can conclude that the VDF filter gives poor quality scores compared same to the noise sequence. On the other hand, the VMF filter provides good performance against impulsive noise. We test the performance of two filters using our metric PSNR with CSF. For short viewing distance, the VMF filter is more efficient for the less eventful sequences. For long viewing distance, the VMF filter is more efficient for the most animated sequences.

Abstract. This paper presents an approach where the optical flow between frames of video sequences is estimated according to a pel-recursive strategy through the use of a principal component regression (PCR). This is a simple choice when it comes to treat mixtures of motion vectors due to the fact that it is not essential to have too much knowledge on their statistical properties (although they are supposed to be normal). Local image properties are taken into consideration in order to estimate the 2D motion. The main advantages of the developed procedure are: ( i) the noise distribution is not used directly; and (ii) the types of motion present in neighborhood can be identified, so that a discriminant-type of test can be performed. Preliminary experiments indicate that this approach provides robust estimates of the optical flow.

3. the arrangement, which answers to the question "according to which order to place information on a screen?" (or "how should IO be arranged in a PU?" by logical order, by frequency or by predefined format?). This study is devoted to the layout problem in the TRIDENT project (Tools foR an Interactive Development ENvironmenT) , which is dedicated to highly interactive business -oriented applications. In this project, the placement problem consists of a computer-aided visual placement of interaction objects (IO) included in a more composite IO called Presentation Unit (PU). Two strategies for placing IO within a PU are characterised and investigated : a static two-column based strategy and a dynamic right/bottom strategy. Each strategy decomposes the placement into three partially overlapping dimensions : localisation, dimensioning, and arrangement. A set of simple mathematical relationships is introduced to rate the quality of visual principles gained with the re...