Peer-to-peer multipoint video conferencing with layered video

Due to copyright restrictions, the access to the full text of this article is only available via subscription.A peer-to-peer (P2P) architecture for multipoint video conferencing using layered video coding at the end hosts is proposed. The system primarily targets end points with low bandwidth network connections and enables them to create a multipoint video conference without any additional networking and computing resources beyond what is needed for a point-to-point conference. For P2P multipoint video conferencing applications, wide-area collaboration is significant for connecting participants from different parts around the globe to support collaborative work. In our system, peers collaborate for streaming video, and the motivation behind the use of layered video is to overcome the problem of denying video requests by peers and assure that each participant peer can view any other participant at any configuration. Layered video encoding techniques usable within this architecture are discussed. A protocol for operating the system has been developed, simulated and its performance has been analyzed. Furthermore, a multi-objective optimization approach has been developed to simultaneously minimize the number of base layer receivers and the delay experienced by the peers while maximizing the granted additional requests to support peers having multiple video input bandwidths. The use of the multi-objective optimization scheme is demonstrated through an example scenario and simulations. A prototype has also been implemented, and the system has been formally specified and verified.TÜBİTA

Content-Aware Scalability-Type Selection for Rate Adaptation of Scalable Video

Scalable video coders provide different scaling options, such as temporal, spatial, and SNR scalabilities, where rate reduction by discarding enhancement layers of different scalability-type results in different kinds and/or levels of visual distortion depend on the content and bitrate. This dependency between scalability type, video content, and bitrate is not well investigated in the literature. To this effect, we first propose an objective function that quantifies flatness, blockiness, blurriness, and temporal jerkiness artifacts caused by rate reduction by spatial size, frame rate, and quantization parameter scaling. Next, the weights of this objective function are determined for different content (shot) types and different bitrates using a training procedure with subjective evaluation. Finally, a method is proposed for choosing the best scaling type for each temporal segment that results in minimum visual distortion according to this objective function given the content type of temporal segments. Two subjective tests have been performed to validate the proposed procedure for content-aware selection of the best scalability type on soccer videos. Soccer videos scaled from 600 kbps to 100 kbps by the proposed content-aware selection of scalability type have been found visually superior to those that are scaled using a single scalability option over the whole sequence

Royalty Cost Based Optimization for Video Compression

A video compression standard incorporates many tools and technologies which must be licensed by systems that deploy the standard. The licensing determines the royalty costs that must be paid to the holders of intellectual property on the respective tools. With current abundance of well understood and effective video compression tools, one can imagine the formation of cross cutting tool libraries with tools drawn from different video compression standards. This allows dynamic selection from a large pool of tools, having potentially overlapping functionality, when encoding individual video sequences. In this paper we examine the royalty cost aspect of the scenario where video is encoded using a library of royalty bearing tools by considering encoding that jointly optimizes rate, distortion, and royalty cost. We provide a system that optimizes video delivery under various licensing conditions imposed on tool intellectual property. We present an example of royalty based encoding (using assumed royalty costs) to show the merit of the proposed framework. 1