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Best Student Paper Award at NAB BEIT Conference 2025

The paper “Two-pass Encoding for Live Video Streaming” has been selected as the Best Student Paper at the NAB Broadcast Engineering and IT (BEIT) Conference 2025.

NAB Broadcast Engineering and IT (BEIT) Conference

5–9 April 2025 | Las Vegas, NV, USA

Abstract: Live streaming has become increasingly important in our daily lives due to the growing demand for real-time content consumption. Traditional live video streaming typically relies on single-pass encoding due to its low latency. However, it lacks video content analysis, often resulting in inefficient compression and quality fluctuations during playback. Constant Rate Factor (CRF) encoding, a type of single-pass method, offers more consistent quality but suffers from unpredictable output bitrate, complicating bandwidth management. In contrast, multi-pass encoding improves compression efficiency through multiple passes. However, its added latency makes it unsuitable for live streaming. In this paper, we propose OTPS, an online two-pass encoding scheme that overcomes these limitations by employing fast feature extraction on a downscaled video representation and a gradient-boosting regression model to predict the optimal CRF for encoding. This approach provides consistent quality and efficient encoding while avoiding the latency introduced by traditional multi-pass techniques. Experimental results show that OTPS offers 3.7% higher compression efficiency than single-pass encoding and achieves up to 28.1% faster encoding than multi-pass modes. Compared to single-pass encoding, encoded videos using OTPS exhibit 5% less deviation from the target bitrate while delivering notably more consistent quality.

Authors: Mohammad Ghasempour (AAU, Austria); Hadi Amirpour (AAU, Austria); Christian Timmerer (AAU, Austria)

 

The 2nd IEEE ICME Workshop on Surpassing Latency Limits in Adaptive Live Video Streaming (LIVES’25)

June 30 to July 4, 2025, Nantes, France

Delivering video content from a video server to viewers over the Internet is time-consuming in the streaming workflow and has to be handled to offer an uninterrupted streaming experience. The end-to-end latency, i.e., from the camera capture to the user device, is particularly problematic for live streaming. Some streaming-based applications, such as virtual events, esports, online learning, gaming, webinars, and all-hands meetings, require low latency for their operation. Video streaming is ubiquitous in many applications, devices, and fields. Delivering high Quality-of-Experience (QoE) to the streaming viewers is crucial, while the requirement to process a large amount of data to satisfy such QoE cannot be handled with human-constrained possibilities. Satisfying the requirements of low latency video streaming applications requires the streaming workflow to be optimized and streamlined together, which includes media provisioning (capturing, encoding, packaging, an ingesting to the origin server), media delivery (from the origin to the CDN and from the CDN to the end users), media playback (end user video player). The 2nd workshop on Surpassing Latency Limits in Adaptive Live Video Streaming (LIVES 2025) aims to bring together researchers and developers to satisfy the data-intensive processing requirements and QoE challenges of live video streaming applications through leveraging heuristic and learning-based approaches.

Please click here for more information.

The Graph-Massivizer project team is looking forward to growing the community in 2025!

The Graph-Massivizer Project is glad to announce that their research expands beyond the European borders. The website receives continuous visits from colleagues from US, Canada, China…and the project team is happy to develop connections with top researchers in #graphprocessing wherever they are.

In such context, Radu Prodan presented Graph-Massivizer Project at the Indian Institute of Science (IISc) in #Bangalore, at the invitation of Prof. Yogesh Simmhan.

 

 

Sahar Nasirihaghighi’s Research Stay at Eindhoven University

Eindhoven University of Technology (TU/e) is a top university known for its advanced research and focus on working across different fields. The university’s Biomedical Engineering department is a leader in medical image analysis and related studies.

During my two-month visit to Eindhoven University as a guest researcher, I worked with the Medical Image Analysis group in the Biomedical Engineering department. This group, including a diverse team of researchers and professors, is dedicated to advancing knowledge and solutions in the medical domain. My research focused on a project about robotic-assisted minimally invasive esophagectomy, and I worked with Prof. Pluim and Dr. Al Khalil. This project is very similar to my work at Klagenfurt University, where I focused on surgical video analysis using deep learning under the supervision of Prof. Schoeffmann. The overlap in our research objectives made this an ideal opportunity for collaboration and exchanging ideas.

This enriching experience was made possible through the Young Scientist Mentoring Program, which supports researchers by creating opportunities for networking and international collaboration. The visit not only enhanced my academic growth but also strengthened ties between our research communities, paving the way for future collaborations.

 

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HiPC Distinguished Paper Award goes to….

At the HiPC 2024 (31st IEEE International Conference on High Performance Computing, Data, and Analysis) held in Bengaluru, India from December 18-21, Haleh Dizaji received the HiPC Distinguished Paper Award for the paper “Graph Sampling Quality Prediction for Algorithm Recommendation” written together with Reza Farahani, Joze M. Rozanec, Ahmet Soylu, Dragi Kimovski and Radu Prodan. Radu Prodan who participated in the conference received the award. Congratulations!

 

 

 

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“Final Countdown” Theme Sparks Creative Innovation at Klagenfurt Game Jam”

A remarkable display of game development talent unfolded at the University of Klagenfurt as 64 participants created 16 unique games during the intensive Klagenfurt GSE Jam, held December 13-15, 2024. The event, which welcomed in-person and online participants, challenged developers to create games around the theme “Final Countdown,” resulting in an impressive array of interpretations.

The event commenced with opening remarks from Wilfried Elmenreich and Felix Schniz, launching participants into 48 hours of intensive development. While anchored in the University’s Game Studies and Engineering master program, the jam welcomed developers of all backgrounds, creating a dynamic environment for creative collaboration. Organizers Armin Lippitz, Bodo Thausing, and Tom Tucek structured the event to maximize creative potential while maintaining a supportive atmosphere.

The diversity of submitted games demonstrated remarkable creativity, with developers crafting experiences ranging from intense action games to atmospheric adventures and narrative-driven experiences. Many teams embraced additional challenges known as diversifiers, including “Unconventional Controls,” “Minimalist Style,” and “Unusual Perspectives,” adding extra layers of complexity to their projects. The resulting games were evaluated across multiple categories, including Most Fun Game, Best Art, Best Audio, Best Writing, and Best Use of Theme, ensuring recognition for excellence across all aspects of game development.

Competition was fierce this year, with numerous standout titles demonstrating the participants’ ability to blend innovative gameplay mechanics with creative interpretations of the countdown theme. The event culminated in a game fair showcasing all sixteen titles, highlighting the remarkable achievements possible within a 48-hour development window.

All games from the Klagenfurt GSE Jam are available to play at https://itch.io/jam/klagenfurt-gse-jam-ws24/entries

Paper accepted: ALPHAS: Adaptive Bitrate Ladder Optimization for Multi-Live Video Streaming

Authors: Farzad Tashtarian (Alpen-Adria Universität Klagenfurt, Austria); Mahdi Dolati (Sharif University of Technology, Iran); Daniele Lorenzi (University of Klagenfurt, Austria); Mojtaba Mozhganfar (University of Tehran, Iran); Sergey Gorinsky (IMDEA Networks Institute, Spain); Ahmad Khonsari (University of Tehran, Iran); Christian Timmerer (Alpen-Adria-Universität Klagenfurt & Bitmovin, Austria); Hermann Hellwagner (Klagenfurt University, Austria)

Event: IEEE INFOCOM 2025,  19–22 May 2025 // London, United Kingdom

Abstract: Live streaming routinely relies on the Hypertext Transfer Protocol (HTTP) and content delivery networks (CDNs) to scalably disseminate videos to diverse clients. A bitrate ladder refers to a list of bitrate-resolution pairs, or representations, used for encoding a video. A promising trend in HTTP-based video streaming is to adapt not only the client’s representation choice but also the bitrate ladder during the streaming session. This paper examines the problem of multi-live streaming, where an encoding service performs coordinated CDN-aware bitrate ladder adaptation for multiple live streams delivered to heterogeneous clients in different zones via CDN edge servers. We design ALPHAS, a practical and scalable system for multi-live streaming that accounts for CDNs’ bandwidth constraints and encoder’s computational capabilities and also supports stream prioritization. ALPHAS, aware of both video content and streaming context, seamlessly integrates with the end-to-end streaming pipeline and operates in real time transparently to clients and encoding algorithms. We develop a cloud-based ALPHAS implementation and evaluate it through extensive real-world and trace-driven experiments against four prominent baselines that encode each stream independently. The evaluation shows that ALPHAS outperforms the baselines, improving quality of experience, end-to-end latency, and per-stream processing by up to 23%, 21%, and 49%, respectively.

 

Paper accepted: Generative AI for Realistic Voice Dubbing Across Languages

Authors: Emanuele Artioli (Alpen-Adria Universität Klagenfurt, Austria), Daniele Lorenzi (Alpen-Adria Universität Klagenfurt, Austria), Farzad Tashtarian (Alpen-Adria Universität Klagenfurt, Austria), Christian Timmerer (Alpen-Adria Universität Klagenfurt, Austria)

Event: ACM 4th Mile-High Video Conference (MHV’25), 18–20 February 2025 |
Denver, CO, USA

Abstract: The demand for accessible, multilingual video content has grown significantly with the global rise of streaming platforms, social media, and online learning. The traditional solutions for making content accessible across languages include subtitles, even generated ones, as YouTube offers, and synthesizing voiceovers, offered, for example, by the Yandex Browser. Subtitles are cost-effective and reflect the original voice of the speaker, which is often essential for authenticity. However, they require viewers to divide their attention between reading text and watching visuals, which can diminish engagement, especially for highly visual content. Synthesized voiceovers, on the other hand, eliminate this need by providing an auditory translation. Still, they typically lack the emotional depth and unique vocal characteristics of the original speaker, which can affect the viewing experience and disconnect audiences from the intended pathos of the content. A straightforward solution would involve having the original actor “perform” in every language, thereby preserving the traits that define their character or narration style. However, recording actors in multiple languages is impractical, time-intensive, and expensive, especially for widely distributed media.

By leveraging generative AI, we aim to develop a client-side tool, to incorporate in a dedicated video streaming player, that combines the accessibility of multilingual dubbing with the authenticity of the original speaker’s performance, effectively allowing a single actor to deliver their voice in any language. To the best of our knowledge, no current streaming system can capture the speaker’s unique voice or emotional tone.

Paper accepted: Adaptive Quality and Energy Enhancement in Video Streaming with RecABR

Authors: Daniele Lorenzi (Alpen-Adria Universität Klagenfurt, Austria), Farzad Tashtarian (Alpen-Adria Universität Klagenfurt, Austria), Christian Timmerer (Alpen-Adria Universität Klagenfurt, Austria)

Event: ACM 4th Mile-High Video Conference (MHV’25), 18–20 February 2025 |
Denver, CO, USA

Abstract: HTTP Adaptive Streaming (HAS) dominates video delivery but faces sustainability issues due to its energy demands. Current adaptive bitrate (ABR) algorithms prioritize quality, neglecting the energy costs of higher bitrates. Super-resolution (SR) can enhance quality but increases energy use, especially for GPU-equipped devices in competitive networks. RecABR addresses these challenges by clustering clients based on device attributes (e.g., GPU, resolution) and optimizing parameters via linear programming. This reduces computational overhead and ensures energy-efficient, quality-aware recommendations. Using metrics like VMAF and compressed SR models, RecABR minimizes storage and processing costs, making it scalable for CDN edge deployment.

Mathias Lux
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First Game Creators Barcamp Held at the University of Klagenfurt

Local game developers and researchers gathered for the inaugural Game Creators Barcamp on Friday, December 6th, at the University of Klagenfurt. The event featured discussions on game development, educational technologies, and industry funding opportunities.

The first Barcamp drew a small but engaged group of participants who explored various game design and development topics. Discussions covered diverse areas, including the story behind the game Electric Alps, potential improvements in language learning through gamification, particularly for teaching irregular German verbs, and an examination of game theory in puzzle game design. The attendees also provided an overview of funding schemes available for game studios. Plans are underway for the next Barcamp, scheduled for spring, hoping to increase participant numbers.