More and more free multi-party video conferencing applications are readily available over the Internet and both Server-to-Client (S/C) or Peer-to-Peer (P2P) technologies are used. Investigating their mechanisms, analyzing their system performance, and measuring their quality are important objectives for researchers, developers and end users. In this paper, we take four representative video conferencing applications and reveal their characteristics and different aspects of Quality of Experience. Based on our observations and analysis, we recommend to incorporate the following aspects when designing video conferencing applications: 1) Traffic load control/balancing algorithms to better use the limited bandwidth resources and to have a stable conversation; 2) Use traffic shaping policy or adaptively re-encode streams in real time to limit the overall traffic.

This work is, to our knowledge, the first measurement work to study and compare mechanisms and performance of existing free multi-party video conferencing systems.

https://www.nas.ewi.tudelft.nl/people/Piet/papers/Networking2010_multiparty_video.pdf

Measurement study of multi-party video conferencing

A new peer-to-peer architecture for multipoint video conferencing that targets end points with low bandwidth network connections (single video in and out) is presented. It enables end points to create a multipoint conference without any additional networking and computing resources than what is needed for a point-to-point conference. The new architecture is based on layered video coding with two layers at the end points. It allows each conference participant to see any other participant at any given time under all multipoint configurations of any number of users, with a caveat that some participants may have to receive only the base layer video. Layered encoding techniques usable within this architecture are described. A protocol for implementation of the new approach has been developed and simulated. Its performance is analyzed.

/pdf/peer-to-peer-multipoint-video-conferencing-using-layered-g0oiqqusbg.pdf

Peer-to-Peer Multipoint Video Conferencing using Layered Video

A peer-to-peer architecture for multipoint videoconferencing is presented. Each conference participant may have asymmetric and dissimilar bandwidth connections to the Internet. The solution does not require additional hardware, as in multipoint control units, or network infrastructure support such as multicast. Without creating any additional demand on the networking and computing resources needed for a point-to-point videoconference, this architecture can extend it into a multipoint one. A protocol for a completely distributed implementation has been developed and tested on a prototype system extending a point-to-point video phone to a multipoint one. The architecture of the prototype system along with the details of the protocol optimization is discussed. Several performance results are presented.

/pdf/peer-to-peer-multipoint-videoconferencing-on-the-internet-54mn0xv387.pdf

Peer-to-peer multipoint videoconferencing on the Internet

This paper focuses on new technologies that are practically useful for telemedicine. Three representative systems are introduced: a Digital Video Transport System (DVTS), an H.323 compatible videoconferencing system, and Vidyo. Based on some of our experiences, we highlight the advantages and disadvantages of each technology, and point out technologies that are especially targeted at doctors and technicians, so that those interested in using similar technologies can make appropriate choices and achieve their own goals depending on their specific conditions.

/pdf/emerging-technologies-for-telemedicine-1qt9vnbrm4.pdf

Emerging technologies for telemedicine.

Multiparty video conferencing (MPVC) facilitates real-time group interaction between users. While P2P is a natural delivery solution for MPVC, a peer often does not have enough bandwidth to deliver her video to all other peers in the conference. Recently, we have witnessed the popularity of one-view MPVC, where each user only watches full video of another user. One-view MPVC opens up the design space for P2P delivery. In this paper, we explore the feasibility of a pure P2P solution for one-view MPVC. We characterize the video source rate region achievable through video relays between peers. For both homogeneous and heterogeneous MPVC systems, we establish tight universal video rate lower bounds that are independent of the number of peers, the number of video sources, and the specific viewing relations between peers. We further propose, P2P video relay designs to approach the maximal video rate region. Through numerical simulations, we verified that the derived lower bounds are indeed tight bounds, and the proposed bandwidth allocation algorithm can achieve a close-to-optimal peer upload bandwidth utilization. Our results demonstrate that P2P is a promising solution for one-view MPVC. Insights obtained from our study can be used to guide the design of P2P MPVC systems.

/pdf/enabling-p2p-one-view-multiparty-video-conferencing-1dsmcpe3g6.pdf

Enabling P2P One-View Multiparty Video Conferencing

A peer-to-peer architecture for multipoint video conferencing is presented. The architecture targets end points with symmetrical, low bandwidth connections. Without creating any additional demand on the networking and computing resources needed for a point-to-point video conference, this architecture can extend it into a multipoint one. A protocol for a completely distributed implementation has been developed and tested on a prototype system extending a point-to-point video phone to a multipoint one.

Tahir Celebi

Papers

Peer-to-peer multipoint videoconferencing on the Internet

Peer-to-peer multipoint videoconferencing

P2P Multi-Point Videoconferencing on the Internet.