Special Issue on Sustainable Multimedia Communications and Services, IEEE COMSOC MMTC Communications – Frontiers

Title: Towards Low-Latency and Energy-Efficient Hybrid P2P-CDN Live Video Streaming

Authors: Reza Farahani, Christian Timmerer, and Hermann Hellwagner

Abstract: Streaming segmented videos over the Hypertext Transfer Protocol (HTTP) is an increasingly popular approach in both live and video-on-demand (VoD) applications. However, designing a scalable and adaptable framework that reduces servers’ energy consumption and supports low latency and high quality services, particularly for live video streaming scenarios, is still challenging for Over-The-Top (OTT) service providers. To address such challenges, this paper introduces a new hybrid P2P-CDN framework that leverages new networking and computing paradigms, i.e., Network Function Virtualization (NFV) and edge computing for live video streaming. The proposed framework introduces a multi-layer architecture and a tree of possible actions therein (an action tree), taking into account all available resources from peers, edge, and CDN servers to efficiently distribute video fetching and transcoding tasks across a hybrid P2P-CDN network, consequently enhancing the users’ latency and video quality. We also discuss our testbed designed to validate the framework and compare it with baseline methods. The experimental results indicate that the proposed framework improves user Quality of Experience (QoE), reduces client serving latency, and improves edge server energy consumption compared to baseline approaches.

International Conference on Visual Communications and Image Processing (IEEE VCIP’23)


Authors: Vignesh V Menon, Reza Farahani, Prajit T Rajendran, Samira Afzal, Klaus Schoeffmann, Christian Timmerer

Abstract: With the emergence of multiple modern video codecs, streaming service providers are forced to encode, store, and transmit bitrate ladders of multiple codecs separately, consequently suffering from additional energy costs for encoding, storage, and transmission. To tackle this issue, we introduce an online energy-efficient Multi-Codec Bitrate ladder Estimation scheme (MCBE) for adaptive video streaming applications. In MCBE, quality representations within the bitrate ladder of new-generation codecs (e.g., HEVC, AV1) that lie below the predicted rate-distortion curve of the AVC codec are removed. Moreover, perceptual redundancy between representations of the bitrate ladders of the considered codecs is also minimized based on a Just Noticeable Difference (JND) threshold. Therefore, random forest-based models predict the VMAF of bitrate ladder representations of each codec. In a live streaming session where all clients support the decoding of AVC, HEVC, and AV1, MCBE achieves impressive results, reducing cumulative encoding energy by 56.45%, storage energy usage by 94.99%, and transmission energy usage by 77.61% (considering a JND of six VMAF points). These energy reductions are in comparison to a baseline bitrate ladder encoding based on current industry practice.

The Interactive Video Retrieval for Beginners (IVR4B) special session and competition took place on September 21, 2023, at the International Conference on Multimedia Indexing (CBMI2023) in Orleans, France. https://cbmi2023.org/

We are happy to announce that Klaus Schoeffmann could save the BEST KIS-VISUAL award for this competition, with his interactive video search system diveXplore.







From September 19-21, professors and students from the University of Klagenfurt met with FH Villach, FH St. Pölten, and HTL Villach students for the Future of Education Hackathon. During this event, they were split into three groups to work on concepts and solutions in AI, digital platform ecosystems, and gamification to solve various problems and improve the future of education. The gamification group consisted of Samuele and Elias from the master’s program Game Studies and Engineering and Noah and David from the HTL Villach for Informatics. Their supervisors during this event were Mathias Lux, Sebastian Uitz, and Wolfgang Hoi, with expert support from Fabian Schober on the event’s second day.

Throughout the 3 day event, they worked on a solution to utilize gamification to foster the development of skills, knowledge, and competencies and generate a motivating, clear, and exciting journey. Their solution consisted of a gamified study tracker, which tracks the student’s progress, recommends additional courses, and keeps the student motivated via quests and competition. This tracker is combined with the Study Buddy, an AI chatbot to interact with the student more naturally and ask them about their study, presents quests, and helps if the motivation drops. The final step of their solution was the “Job Tinder” which can be used to look for possible jobs in a fun way and which will recommend jobs based on the information gathered via the student tracker.

On the event’s last day, all solutions were pitched to a Jury, and after a lengthy discussion, the gamification team was elected as the winning team.

A video summary of this event is available via the following link. German only.

HACKATHON | The Future Of Education


The GraphMassivizer plenary meeting is underway in #Walldorf, hosted by our valued partner metaphacts GmbH

We’re thrilled to gather for three days of collaboration, sharing project results, and planning upcoming activities.

Radu Prodan, Laurentiu Vasiliu, Irina Schmidt, Roberta Turra, Peter Haase, Richard Lloyd Stevens, Alexandru Iosup, Ana-Lucia Varbanescu, Nuria De Lama, Reza Farahani.

From September 7-9, nearly 40 participants joined us at AAU Klagenfurt to discuss and theorise about the theme of “Video Game Cultures: Exploring New Horizons.” VGC is a recurring conference reinstated after the lockdowns, coordinated between universities and scholars from the US, UK, Czech Republic, Austria, and Germany. This year’s conference was an organisational collaboration between ITEC and the Department of English at AAU; Felix Schniz and René Schallegger were the local organising chairs. We had the pleasure to not only listen to a wonderful variety of perspectives and approaches from our participants in and around the field of Game Studies but also to cultivate a kind and constructive atmosphere. Many thanks to everyone who helped set up this year’s VGC, especially our sponsors!


Authors: Reza Saeedinia (University of Tehran), S. Omid Fatemi (University of Tehran),Daniele Lorenzi (Alpen-Adria Universität Klagenfurt), Farzad Tashtarian (Alpen-Adria Universität Klagenfurt),  Christian Timmerer (Alpen-Adria Universität Klagenfurt)

Abstract: Live user-generated content (UGC) has increased significantly in video streaming applications. Improving the quality of experience (QoE) for users is a crucial consideration in UGC live streaming, where a user can be both a subscriber and a streamer. Resource allocation is an NP-complete task in UGC live streaming due to many subscribers and streamers with varying requests, bandwidth limitations, and network constraints. In this paper, to decrease the execution time of the resource allocation algorithm, we first process streamers’ and subscribers’ requests and then aggregate them into a limited number of groups based on their preferences. Second, we
perform resource allocation for these groups that we call communities. We formulate the resource allocation problem for communities into an optimization problem. With an efficient aggregation of subscribers and streamers at the core of the proposed architecture, the computational complexity of the optimization problem is reduced, consequently improving QoE. This improvement occurs because of the prompt reaction to the bandwidth fluctuations and, subsequently, appropriate resource allocation by the proposed model. We conduct experiments in various scenarios. The results show an average of 41% improvement in execution time. To evaluate the impact of bandwidth fluctuations on the proposed algorithm, we employ two network traces: AmazonFCC and NYUBUS. The results show 4%, and 28% QoE improvement in a scenario with 5
streamers over the AmazonFCC and the NYUBUS network traces, respectively.

Link: 13th International Conference on Computer and Knowledge Engineering (ICCKE)

Title: Designing A Sustainable Serverless Graph Processing Tool on the Computing Continuum

Abstract: Graph processing has become increasingly popular and essential for solving complex problems in various domains, like social networks. However, processing graphs at a massive scale poses critical challenges, such as inefficient resource and energy utilization. To bridge such challenges, the Graph-Massivizer project, funded by the Horizon Europe research and innovation program, conducts research and develops a high-performance, scalable, and sustainable platform for information processing and reasoning based on the massive graph (MG) representation of extreme data. This paper presents an initial architectural design for the Choreographer, one of the five Graph-Massivizer tools. We explain Choreographer’s components and their collaboration with other Graph-Massivizer tools. We demonstrate how Choreographer can adopt the emerging serverless computing paradigm to process Basic Graph Operations (BGOs) as serverless functions across the computing continuum efficiently. Moreover, we present an early vision of our federated Function-as-a-Service (FaaS) testbed, which will be used to conduct experiments and assess Choreographer performance.


Kurt Horvath presented the paper titled A distributed geofence-based discovery scheme for the computing Continuum at 29th International European Conference on Parallel and Distributed Computing (EURO-PAR 2023)

Authors: Kurt Horvath, Dragi Kimovski, Christoph Uran, Helmut Wöllik, and Radu Prodan

Abstract: Service discovery is a vital process that enables low latency provisioning of Internet of Things applications across the computing continuum. Unfortunately, it becomes increasingly difficult to identify a proper service within strict time constraints due to the high heterogeneity of the computing continuum. Moreover, the plethora of network technologies and protocols commonly used by the Internet of Things applications further hinders service discovery. To address these issues, we introduce a novel mobile edge service discovery algorithm named Mobile Edge Service Discovery using the DNS (MESDD), which utilizes intermediate code to identify a suitable service instance across the computing continuum based on the naming scheme used to identify the users’ location. MESDD utilizes geofences to aid this process, which enables fine-grained resource discovery. We deployed a real-life distributed computing continuum testbed and compared MESDD with three related methods. The evaluation results show that MESDD outperforms the other approaches by 60% after eight discovery iterations.


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