Video Quality

In MPEG coding, there are three types of encoded pictures. Since these picture coding types have different importance of data content, the cell loss of each picture coding type affects the video quality differently in MPEG video transmission through ATM networks. This paper analyzed the per-session cell loss properties of MPEG video traffic in an ATM switching node in both the steady-state case and the transient case considering each picture type. In the analysis, a 3-state Markov modulated Bernoulli process (MMBP) is proposed as a traffic model for MPEG video which is tractable analytically. Numerical results revealed the influence of the picture transmission pattern on the cell loss properties of each picture coding type

Few would argue that music is basic to the human experience, and that at its best, it can unify, transform, and transcend. Accordingly, it is not only valuable to experience music but also to nurture the innate musical ability that every human possesses. In resource-limited environments, the prospect of musical development through the study of an instrument can be sparse. In particular, children in resource-poor rural settings may have little opportunity to discover the delight of expressing the inexpressible through a musical instrument. ...

Degradation of network performance during video transmission may lead to disturbing visual artifacts. Some packets might be lost, corrupted or delayed, making it impossible to properly decode the video data on time at the receiver. The quality of the error-concealment technique, as well as the spatial and temporal position of the artifacts have a large impact on the perceived quality after decoding. In this paper, we use the spatial scalability feature of Scalable Video Coding (SVC) for error-concealment. This enables the transmission of a lower resolution video with a higher robustness, for example using unequal error protection. Under the assumption that only the higher resolution video would be affected, we evaluated the visual impact of packet losses in a large scale subjective video quality experiment using the Absolute Category Rating method. The number of impairments, the duration, and the interval between impairments as well the quality of the encoded lower resolution video are varied in a systematic evaluation. This allows for analyzing the influence of each factor both independently and jointly.

We present an efficient reduced-reference video quality assessment method based on local harmonic strength (LHS) feature. LHS is based on harmonics gain and loss information derived through the discriminative analysis of harmonics strength computed from gradient pictures. Harmonics gain and loss correspond with the two most prominent compression artifacts, namely blockiness and blurriness. To make the method effective for continuous monitoring of video quality, it is necessary to minimize the reduced-reference overhead data whilst keeping the accuracy of the quality meter sufficiently high. For the LHS-based method, we recommend quantization of the LHS feature, temporal sampling, and block selection method, either with or without segmentation-based block classification. A typical reduced-reference low overhead data rate (around 160-400 bps) with good prediction performance (0.86-0.88 Pearson correlations against mean opinion score) for broadcast type video sequences in VQEG Test Phase-I data sets has been achieved by the proposed method.

— The main issue in Digital Terrestrial Television and in IPTV networks is the Quality of Experience received by the end users. For this reason, mechanisms to automatically measure the video quality of the images received by the user are needed. In this paper, we analyze video quantization in order to determine an optimal quantizer_scale factor value for its transmission. Then, it is used as an automatic measure to improve the video quality received by the end user. The paper shows the measurements taken for Objective and subjective Video Quality, Video Quality Metric and the bandwidth consumed for several types of video quality. We use the jitter, delay and lost packets measurements in order to take the appropriate quantizer. Finally, we show the visual comparison between a high quantizer_scale factor and a reference video. Our work shows that an optimal quantizer_scale factor can be used to save bandwidth in an IPTV network or to improve the Video Quality for the same bandwidth co...

The work in this paper examines the effects of group of pictures on H.264 multiview video coding bitstream over an erroneous network with different error rates. The study considers analyzing the bitrate performance for different GOP and error rates to see the effects on the quality of the reconstructed multiview video. However, by analyzing the multiview video content it is possible to identify an optimum GOP size depending on the type of application used. In a comparison test, the H.264 data partitioning and the multi layer data partitioning technique with different error rates and GOP are evaluated in terms of quality perception. The results of the simulation confirm that Multi-layer data partitioning technique shows a better performance at higher error rates with different GOP. Further experiments in this work have shown the effects of GOP in terms of visual quality and bitrate for different multiview video sequences

Abstract—Worldwide Interoperability for Microwave Access is an emerging wireless access networks offering high data rates and good range. These features, in addition to moderate installation and maintenance costs, make it an appealing last-mile delivery net-work for IPTV and ...

The multiview video coding (MVC) standard is currently under development by the Joint Video Team as an extension of the advanced video coding (H. 264/AVC) standard. An MVC encoder compresses more than one viewpoint of a scene captured by different cameras. Redundancies between views can be used for inter-view prediction in encoding as well as error concealment in decoding. In this paper, a new algorithm utilizing motion information of pictures from other views to conceal a lost picture is proposed. The ...

H.264 Scalable Video Coding (SVC) is an extension to the Advanced Video Coding (AVC) H.264 standard which provides efficient scalability functionalities on top of the high coding efficiency of H.264/AVC. SVC allows for temporal, spatial, and quality scalability of the output video stream, encoding the video information into an H.264/AVC base layer and a series of enhancement layers which incrementally improve the quality, increase screen resolution and/or frame rate. SVC is particularly suited for mobile TV reception, since the received video quality is adaptable to variable reception conditions and heterogeneous receiver capabilities. However, mobile TV Digital Video Broadcasting (DVB) standards such as DVB-H and DVB-SH were designed prior to the introduction of SVC, and therefore the underlying transmission protocols are not optimized for scalable video delivery. In this overview paper, we review recently proposed solutions for SVC stream adaptation on the underlying DVB-H/SH protocols, and point out novel technical solutions that are currently under consideration for the next generation mobile broadcasting standard DVB-NGH.

Abstract: We describe a system for multipoint videoconferencing that offers extremely low end-to-end delay, low cost and complexity, and high scalability, alongside standard features associated with high-end solutions such as rate matching and per-sonal video layout. ...