Emanuele Quacchio

Adaptation algorithm for adaptive streaming over HTTP

Internet video makes up a significant part of the Internet traffic and its fraction is constantly growing. In order to guarantee best user experience throughout different network access technologies with dynamically varying network conditions, it is fundamental to adopt technologies enabling a proper delivery of the media content. One of such technologies is adaptive streaming. It allows to dynamically adapt the bit-rate of the stream to varying network conditions. There are various approaches to adaptive streaming. In our work, we focus on the receiver-driven approach where the media file is subdivided into segments, each of the segments is provided at multiple bit-rates, and the task of the client is to select the appropriate bit-rate for each of the segments. With this approach, the challenges are (i) to properly estimate the dynamics of the available network throughput, (ii) to control the filling level of the client buffer in order to avoid underflows resulting in playback interruptions, (iii) to maximize the quality of the stream, while avoiding unnecessary quality fluctuations, and, finally, (iv) to minimize the delay between the users request and the start of the playback. During our work, we designed and implemented a receiver-driven adaptation algorithm for adaptive streaming that does not rely on cross-layer information or server assistance. We integrated the algorithm with a prototype implementation of a streaming client based on the MPEG DASH (Dynamic Adaptive Streaming over HTTP) standard. We evaluated the implemented prototype in real-world scenarios and found that it performes remarkably well even under challenging network conditions. Further, it exhibits stable and fair operation if a common link is shared among multiple clients.

Peer-to-peer streaming of scalable video in future Internet applications

Scalable video delivery over peer-to-peer networks appears to be key for efficient streaming in emerging and future Internet applications. Contrasting the conventional server-client approach, here, video is delivered to a user in a fully distributed fashion. This is, for instance, beneficial in cases where a high demand for a particular video content is imposed, as different users can receive the same data from different peers. Furthermore, due to the heterogeneous nature of Internet connectivity, the content needs to be delivered to a user through networks with highly varying bandwidths. Moreover, content needs to be displayed on a variety of devices featuring different sizes, resolutions, and computational capabilities. If video is encoded in a scalable way, it can be adapted to any required spatio-temporal resolution and quality in the compressed domain, according to a peer bandwidth and other peers¿ context requirements. This enables efficient low-complexity content adaptation and interoperability for improved peer-to-peer streaming in future Internet applications. An efficient piece picking and peer selection policy enables high quality of service in such a streaming system.

A study of an hybrid CDN-P2P system over the PlanetLab network

In this work we propose an hybrid CDN-P2P architecture for video contents delivery based on the NextShare platform. Experiments were conducted over the PlanetLab network using a number of peers which encompass real network behaviors. Results show that although the NextShare is based on the original BitTorrent file sharing mechanism, the implemented tools can efficiently deliver video over a heterogeneous and time varying network if peers can rely on an intermediate distribution layer between the CDN and the final users. Among the other benefits, CDN edge servers are significantly offloaded and peers can experience low start-up delays. Architecture design and simulation results are taking place in the context of the European FP7 project COAST.

Performance Analysis of Scalable Video Adaptation: Generic versus Specific Approach

This paper provides a performance analysis of adaptation approaches designed for scalable media resources. In particular, we investigate the streaming of media resources compliant to the scalable video coding (SVC) extensions of advanced video coding (AVC) within heterogeneous environments, i.e., terminals and networks with different capabilities. Therefore, we have developed a test-bed in order to analyze two different approaches for the adaptation of scalable media resources, namely a generic approach that is applicable independently of the actual scalable coding format used and a specific approach especially built for SVC. The results show that if adaptation is required the generic approach clearly outperforms the approach specifically built for SVC.

An interoperable multimedia delivery framework for scalable video coding based on MPEG-21 Digital Item Adaptation

In this paper we present an interoperable multimedia delivery framework for scalable video coding based on MPEG-21 digital item adaptation (DIA). In can be used to transmit scalable video contents within heterogeneous usage environments where the properties of the usage environment (e.g., terminal/network capabilities) may change dynamically during the streaming session. The usage environment is signaled by interoperable description formats provided by the DIA standard. Additionally, the adaptation itself is done by exploiting the standardpsilas generic adaptation approach, i.e., independent of the actual coding format. Thus, the overall framework is also applicable for other scalable coding formats.

An HTML5 player for a gstreamer based MPEG DASH client

The proposed demo shows how a streaming client compliant with MPEG DASH [1] standard and developed using a GStreamer media framework [2], can be integrated into an HTML5 enabled web browser. Through a non-standard interface, the GStreamer adaptive streaming client can be controlled by a JavaScript engine implemented in the web browser.

An interoperable delivery framework for scalable media resources

In this article an interoperable framework for the delivery of scalable media resources (e.g., in the standardized scalable video coding format) is presented. The framework provides support for video on demand as well as multicast streaming, and performs efficient, generic, and interoperable adaptation of streamed content based on MPEG- 21 Digital Item Adaptation. The server as well as the clients of the streaming framework implement the MPEG Extensible Middleware and utilize the MPEG Query Format for querying the available media resources. The framework has been fully integrated into the VLC media player. The architecture for both VoD and multicast is presented in detail. Finally, a comparison in terms of performance of the generic MPEG-21 metadata-based adaptation approach to an SVC-specific adaptation approach is provided.

3D graphics compression and rendering framework

This paper presents a complete system for computer graphics compression and transmission showing MPEG-4 graphics compression standard tool performance to encode 3D graphics objects. We employed a web based receiver to decode and render 3D objects. We provide a compression evaluation of user generated scanned 3D body models, which are huge in size and presented in XML format. A web based daemon is developed that can receive, decode and render such encoded 3D graphics objects.

A Web-based Framework for Compressed 3D Objects: Downloading and Rendering

This paper is focused on proofing the concept of a web based receiver to download, decode and render 3D objects. It demonstrates the effectiveness in performances when compressed 3D objects are used. It also enlightens the advantages for downloading and rendering in web browsers at different compression environments. It revealed that web-based receiver was useful for downloading, decoding and rendering 3D objects. Downloading time of compressed and uncompressed files was dependent on internet speed while decoding time upon client processing power. The 3D compressed objects took less download/decoding time as compared to 3D uncompressed download time at low (512 Kbps) internet speed. At 2 Mbps, time was not dependent to file sizes. At 10 Mbps, the process was amazingly inversed as times taken by compressed files were more than uncompressed files. This performance evaluation confirmed effectiveness of using compressed 3D objects over uncompressed ones at low speed. The work can also be extended for dynamic 3D objects and animations in future.