ATHENA Christian Doppler (CD) Laboratory

IEEE International Conference on

Acoustics, Speech, and Signal Processing (ICASSP)

14-19 April 2024, Seoul, Korea

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Hadi Amirpour (AAU, Austria), Jingwen Zhu (University of Nantes, France), Patrick Le Callet (University of Nantes, France), and Christian Timmerer (AAU, Austria)

Abstract: In HTTP Adaptive Streaming (HAS), a video is encoded at multiple bitrate-resolution pairs, referred to as representations, which enables users to choose the most suitable representation based on their network connection. To optimize the set of bitrate-resolution pairs and improve the Quality of Experience (QoE) for users, it is of utmost importance to measure the quality of the representations. VMAF is a highly reliable metric used in HAS to assess the quality of representations. However, in practice, using it for optimization can be a very time-consuming process, and it is infeasible for live streaming applications. To tackle its high complexity, our paper introduces a new method called VQM4HAS, which extracts low-complexity features including (i) video complexity features, (ii) bitstream features logged during the encoding process, and (iii) basic video quality metrics. These extracted features are then fed into a regression model to predict VMAF.
Our experimental results demonstrate that VQM4HAS achieves a high Pearson correlation coefficients (PCC) with VMAF from 0.95 to 0.96 depending on the resolution, but exhibits significantly less complexity, making it suitable for live streaming scenarios.

IEEE International Conference on

Acoustics, Speech, and Signal Processing (ICASSP)

14-19 April 2024, Seoul, Korea

[PDF]

Mohammad Ghasempour (AAU, Austria), Hadi Amirpour (AAU, Austria), Mohammad Ghanbari (University of Essex, UK), and Christian Timmerer (AAU, Austria)

Abstract: With the ubiquity of video streaming, optimizing the delivery of video content while reducing energy consumption has become increasingly critical. Traditional adaptive streaming relies on a fixed set of bitrate-resolution pairs, known as bitrate ladders, for encoding. However, this one-size-fits-all approach is suboptimal for diverse video content. As a result, per-title encoding approaches dynamically select the bitrate ladder for each content. In this paper, we address the pressing issue of increasing energy consumption in video streaming by introducing GreenRes, a novel approach that goes beyond traditional quality-centric resolution selection. Instead, GreenRes considers both video quality and energy consumption to construct an optimal bitrate ladder tailored to the unique characteristics of each video content.
To achieve this, GreenRes, similar to per-title encoding, encodes each video content at various resolutions, each with a set of bitrates. It then establishes a maximum acceptable quality drop threshold and selects resolutions that not only maintain video quality above this threshold, but also minimize energy consumption. Our experimental results demonstrate a 30.82% reduction in energy consumption on average, while ensuring a maximum quality drop of 0.53 Video Multimethod Assessment Fusion (VMAF) points.

Elsevier Signal Processing

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Lingfeng Qu (Guangzhou University, China), Hui Lu (Guangzhou University, China), Peng Chen (Guangzhou University, China),  Hadi Amirpour (Alpen-Adria-Universität Klagenfurt, Austria), and Christian Timmerer (Alpen-Adria-Universität Klagenfurt, Austria)

Abstract:

On behalf of ISO and IEC, this certificate is awarded to

Christian Timmerer

Project Editor in ISO/IEC|TC 1/SC 29/WG 3, MPEG Systems

In recognition of his excellent service to ISO/lEC JTC 1/SC 29, in particular, his exceptional contributions to the development of ISO/EC 23009-2:2020

April 2022

Klagenfurt, November 29, 2023

Reza Ebrahimi successfully defended his Master Thesis on “Quality of Experience Evaluation of Stall Events and Quality Switches in Game Streaming“.

Abstract: The exponential growth of computer game streaming has led to the development of Quality of Experience (QoE) metrics to evaluate user satisfaction and enjoyment during online gameplay and live streaming. Adaptive Bitrate (ABR) streaming is a recent technology that has been suggested to improve QoE. This method enhances the streaming experience, upholds visual quality, minimizes stall events, and boosts player retention. It achieves this by estimating network bottlenecks and selecting appropriate versions of the content that best match the available bandwidth rather than adjusting encoding parameters. To investigate the correlation between quality switching and stall events, a subjective test was conducted separately and comparatively with 71 participants. For more detailed and in-depth research, video games were analyzed with the Video Complexity Analyzer (VCA) tool and divided into three categories of different genres, camera view, and temporal complexity heatmap from the two sets of normal and action scenes. This study seeks to shed light on three unresolved issues pertinent to QoE in game streaming: (i) the user preferences towards quality switching and stall events across varied scenes and games, (ii) the user inclinations towards either a single, prolonged stall event or multiple, shorter stall events, and (iii) the impact of conspicuous quality switching on the user’s QoE. Results from the study provided valuable insights, both qualitatively and quantitatively. The study found a marked preference among users for quality switching over stall events across all types of game streaming, irrespective of the scene’s intensity. Furthermore, it was observed that multiple short-stall events were generally favored over a single long-stall event in streaming first-person shooting games. Interestingly, approximately half of the participants remained oblivious to quality switching during their game viewing sessions, and among those who noticed a change in quality, the alteration did not significantly impact their perceived QoE.

VCIP 2023
Monday, Dec4, 2023
https://vcip2023.iforum.biz/page/goto

Lectures:

• Hadi Amirpour, AAU, AT
• Christian Timmerer, AAU, AT

Abstract: The applications of video streaming are the primary drivers of Internet traffic, as over 82% of IP traffic in 2022. HTTP Adaptive Streaming (HAS) is the prevailing technology to stream live and video-on-demand (VoD) content over the Internet. In HAS, firstly, the video is split into smaller chunks, referred to as segments, each characterized by a short playback time interval. Segments are then encoded at multiple representations (bitrate-resolution pairs), referred to as the bitrate ladder. The clients select the highest possible quality representation for the next segment, which adapts to the current network condition and device type. In this way, HAS enables the continuous delivery of live and VoD content over the Internet. As the demand for video streaming applications is on the rise, new generations of video codecs and video content optimization algorithms are being developed. This tutorial first presents a detailed overview of video codecs, in particular the most recent standard video codec, i.e., Versatile Video Coding (VVC). On top of the video codecs, per-title encoding methods, which optimize bitrate ladders over characteristics of videos, are then introduced. It will be presented how representations are selected in a way that bitrate ladders are optimized over various dimensions, including spatial resolution, frame rate, energy consumption, device type, and network condition. Next, novel methods that optimize bitrate ladders for live video streaming without adding noticeable latency are introduced. Finally, fast multi-rate encoding approaches that reduce the encoding time and cost are introduced.

At Christian Doppler laboratory ATHENA, we offer an internship*)**) for 2024 for Master Students, and we kindly request your applications by the 19th of January 2024 with the following data (in German or English):

• CV
• Record of study/transcript (“Studienerfolgsnachweis”)

*) A 3 months period in 2024 (with an exact time slot to be discussed) with the possibility to spend up to 1-month at the industrial partner; 20h per week “Universitäts-KV, Verwendungsgruppe C1, studentische Hilfskraft”
**) Depending on whether the funding gets approval from the CDG.

Please send your application by email to christian.timmerer@aau.at.

About ATHENA: The Christian Doppler laboratory ATHENA (AdapTive Streaming over HTTP and Emerging Networked MultimediA Services) is jointly proposed by the Institute of Information Technology (ITEC; http://itec.aau.at) at Alpen-Adria-Universität Klagenfurt (AAU) and Bitmovin GmbH (https://bitmovin.com) to address current and future research and deployment challenges of HAS and emerging streaming methods. AAU (ITEC) has been working on adaptive video streaming for more than a decade, has a proven record of successful research projects and publications in the field, and has been actively contributing to MPEG standardization for many years, including MPEG-DASH; Bitmovin is a video streaming software company founded by ITEC researchers in 2013 and has developed highly successful, global R&D and sales activities and a world-wide customer base since then.

The aim of ATHENA is to research and develop novel paradigms, approaches, (prototype) tools, and evaluation results for the phases

1. multimedia content provisioning,
2. content delivery, and
3. content consumption in the media delivery chain as well as for
4. end-to-end aspects, with a focus on, but not being limited to, HTTP Adaptive Streaming (HAS).

The new approaches and insights are to enable Bitmovin to build innovative applications and services to account for the steadily increasing and changing multimedia traffic on the Internet.