Electrical and Electronics Engineering MS Thesis Defense by Rıza Arda Kırmızıoğlu






Title: Multi-party WebRTC Videoconferencing using Scalable Video: From Best-Effort Over-the-top to Managed Value-Added Services


Speaker: Rıza Arda Kırmızıoğlu


Time: April 30, 2019, 10:00


Place: ENG 208

Koç University

Rumeli Feneri Yolu

Sariyer, Istanbul

Thesis Committee Members:

Prof. Ahmet Murat Tekalp (Advisor, Koç University)

Prof. Öznur Özkasap (Koç University)

Assistant Prof. Ali Cengiz Beğen (Ozyegin University)


At present, multi-party WebRTC videoconferencing can be configured in mesh or selective forwarding unit (SFU) architectures over the best-effort Internet. Scalable video coding (SVC) enables efficient service to peers with heterogenous network connections and terminals. In the mesh architecture each peer sends a separate video stream to each other peer where peer upload bandwidth capacity is not enough as the number of peers increase, and the peer with least download bandwidth capacity becomes limiting factor for the rest of the peers because of single non-SVC encoder. SVC enabled SFU architecture, where each peer sends a single upstream video to a central SFU, requires high capacity servers with high bandwidth network connection and the SFU becomes a single point of failure. Also, SFU architecture has more network resource consumption and end-to-end delay performance comapring to mesh architecture. To these effects, we propose one SVC enabled best-effort streaming architecture for mesh connection and three network service provider (NSP) managed SVC enabled multi-party WebRTC architectures with i) mesh, ii) distributed edge-SFU and iii) software-defined network (SDN) assisted IP multicast. Proposed best-effort mesh connection technique solves limiting overall service quality effect of least receiving peer by embedding motion-adaptive SVC. Yet, best-effort videoconferencing services require very quick responsiveness for variant network conditions. Proposed NSP-managed architectures solves this basic problem by bandwidth allocation for WebRTC services. NSP-Managed mesh architecture has the best service quality comparing to proposed best-effort and default WebRTC mesh implementations, however, it still suffers from required high upload bandwidth capacity of the peers. Distributed edge-SFU architecture introduces a novel SFU streaming type by using multiple SFU servers in a single videoconferencing session. NSP-managed distributed edge-SFU architecture reduces total network resource consumption and end-to-end service delay considerably comparing to default SFU implementation. Nonetheless, this architecture is dependent on distributed service deployment over edge networks. SDN-assisted IP-multicast architecture is a completely new streaming type for multi-party WebRTC services. This architecture overcomes limited uplink capacity, service deployment, and single point of failure drawbacks while having better network resource consumption and the best possible end-to-end service delay performance.