This column provides an overview of the last Video Quality Experts Group (VQEG) plenary meeting, which took place from 12 to 16 December 2022. Around 100 participants from 21 different countries around the world registered for the meeting that was organized online by Brightcove (United Kingdom). During the five days, there were more than 40 presentations and discussions among researchers working on topics related to the projects ongoing within VQEG. All the related information, minutes, and files from the meeting are available online on the VQEG meeting website, and video recordings of the meeting are available on Youtube.
Many of the works presented in this meeting can be relevant for the SIGMM community working on quality assessment. Particularly interesting can be the proposals to update and merge ITU-T recommendations P.913, P.911, and P.910, the kick-off of the test plan to evaluate the QoE of immersive interactive communication systems, and the creation of a new group on emerging technologies that will start working on AI-based technologies and greening of streaming and related trends.
We encourage readers interested in any of the activities going on in the working groups to check their websites and subscribe to the corresponding reflectors, to follow them and get involved.
Overview of VQEG Projects
Audiovisual HD (AVHD)
The AVHD group investigates improved subjective and objective methods for analysing commonly available video systems. Currently, there are two projects ongoing under this group: Quality of Experience (QoE) Metrics for Live Video Streaming Applications (Live QoE) and Advanced Subjective Methods (AVHD-SUB).
In this meeting, there were three presentations related to topics covered by this group. In the first one, Maria Martini (Kingston University, UK), presented her work on converting video quality assessment metrics. In particular, the work addressed the relationship between SSIM and PSNR for DCT-based compressed images and video, exploiting the content-related factor . The second presentation was given by Urvashi Pal (Akamai, Australia) and dealt with video codec profiling with video quality assessment complexities and resolutions. Finally, Jingwen Zhu (Nantes Université, France) presented her work on the benefit of parameter-driven approaches for the modelling and the prediction of a Satisfied User Ratio for compressed videos .
Quality Assessment for Health applications (QAH)
The QAH group works on the quality assessment of health applications, considering both subjective evaluation and the development of datasets, objective metrics, and task-based approaches. Currently there is an open discussion on new topics to address within the group, such as the application of visual attention models and studies to health applications. Also, an opportunity to conduct medical perception research was announced, which was proposed by Elizabeth Krupinski and will take place in the European Congress of Radiology (Vienna, Austria, Mar. 2023).
In addition, four research works were presented at the meeting. Firstly, Julie Fournier (INSA Rennes, France) presented new insights on affinity therapy for people with ASD, based on an eye-tracking study on images. The second presentation was delivered by Lumi Xia (INSA Rennes, France) and dealt with the evaluation of the usability of deep learning-based denoising models for low-dose CT simulation. Also, Mohamed Amine Kerkouri (University of Orleans, France), presented his work on deep-based quality assessment of medical images through domain adaptation. Finally, Jorge Caviedes (ASU, USA) delivered a talk on cognition inspired diagnostic image quality models, emphasising the need of distinguishing among interpretability (e.g., medical professional is confident in making a diagnosis), adequacy (e.g., capture technique shows the right area for assessment), and visual quality (e.g., MOS) in quality assessment of medical contents.
Statistical Analysis Methods (SAM)
The SAM group works on improving analysis methods both for the results of subjective experiments and for objective quality models and metrics. The group is currently working on updating and merging the ITU-T recommendations P.913, P.911, and P.910. The suggestion is to make P.910 and P.911 obsolete and make P.913 the only recommendation from ITU-T on subjective video quality assessments. The group worked on the liaison and document to be sent to ITU-T SG12 and will be available in the meeting files.
In addition, Mohsen Jenadeleh (Univerity of Konstanz, Germany) presented his work on collective just noticeable difference assessment for compressed video with Flicker Test and QUEST+.
Computer Generated Imagery (CGI)
CGI group is devoted to analysing and evaluating computer-generated content, with a focus on gaming in particular. The group is currently working in collaboration with ITU-T SG12 on the work item P.BBQCG on Parametric bitstream-based Quality Assessment of Cloud Gaming Services. In this sense, Saman Zadtootaghaj (Sony Interactive Entertainment, Germany) provided an update on the ongoing activities. In addition, they are working on two new work items: G.OMMOG on Opinion Model for Mobile Online Gaming applications and P.CROWDG on Subjective Evaluation of Gaming Quality with a Crowdsourcing Approach. Also, the group is working on identifying other topics and interests in CGI rather than gaming content.
No Reference Metrics (NORM)
The NORM group is an open collaborative project for developing no-reference metrics for monitoring visual service quality. Currently, the group is working on three topics: the development of no-reference metrics, the clarification of the computation of the Spatial and Temporal Indexes (SI and TI, defined in the ITU-T Recommendation P.910), and the development of a standard for video quality metadata.
In relation to the first topic, Margaret Pinson (NTIA/ITS, US), talked about why no-reference metrics for image and video quality lack accuracy and reproducibility  and presented new datasets containing camera noise and compression artifacts for the development of no-reference metrics by the group. In addition, Oliver Wiedeman (University of Konstanz, Germany) presented his work on cross-resolution image quality assessment.
Regarding the computation of complexity indices, Maria Martini (Kingston University, UK) presented a study comparing 12 metrics (and possible combinations) for assessing video content complexity. Vignesh V. Menon (University of Klagenfurt, Austria) presented a summary of live per-title encoding approaches using video complexity features. Ioannis Katsavounidis and Cosmin Stejerean (Meta, US) presented their work on using motion search to order videos by coding complexity, also making available the software in open source. In addition, they led a discussion on supplementing classic SI and TI with improved complexity metrics (VCA, motion search, etc.).
Finally, related to the third topic, Ioannis Katsavounidis (Meta, US) provided an update on the status of the project. Given that the idea is already mature enough, a contribution will be made to MPEG to consider the insertion of metadata of video metrics into the encoded video streams. In addition, a liaison with AOMedia will be established that may go beyond this particular topic. And include best practices on subjective testing, IMG topics, etc.
Joint Effort Group (JEG) – Hybrid
The JEG group was focused on a joint work to develop hybrid perceptual/bitstream metrics and gradually evolved over time to include several areas of Video Quality Assessment (VQA), such as the creation of a large dataset for training such models using full-reference metrics instead of subjective metrics. Currently, the group is working on research problems rather than algorithms and models with immediate applicability. In addition, the group has launched a new website, which includes a list of activities of interest, freely available publications, and other resources.
Two examples of research problems addressed by the group were shown by the two presentations given by Lohic Fotio Tiotsop (Politecnico di Torino, Italy). The topic of the first presentation was related to the training of artificial intelligence observers for a wide range of applications, while the second presentation provided guidelines to train, validate, and publish DNN-based objective measures.
5G Key Performance Indicators (5GKPI)
The 5GKPI group studies the relationship between key performance indicators of new 5G networks and QoE of video services on top of them. In this meeting, Pablo Pérez (Nokia XR Lab, Spain) presented an overview of activities related to QoE and XR within 3GPP.
Immersive Media Group (IMG)
The IMG group is focused on the research on quality assessment of immersive media. The main joint activity going on within the group is the development of a test plan to evaluate the QoE of immersive interactive communication systems. After the discussions that took place in previous meetings and audio calls, a tentative schedule has been proposed to start the execution of the test plan in the following months. In this sense, a new work item will be proposed in the next ITU-T SG12 meeting to establish a collaboration between VQEG-IMG and ITU on this topic.
In addition to this, a variety of different topics related to immersive media technologies were covered in the works presented during the meeting. For example, Yaosi Hu (Wuhan University, China) presented her work on video quality assessment based on quality aggregation networks. In relation to light field imaging, Maria Martini (Kingston University, UK) exposed the main problems related to what light field quality assessment datasets are currently meeting and presented a new dataset. Also, there were three talks by researchers from CWI (Netherlands) dealing with point cloud QoE assessment: Silvia Rossi presented a behavioral analysis in a 6-DoF VR system, taking into account the influence of content, quality and user disposition ; Shishir Subramanyam presented his work related to the subjective QoE evaluation of user-centered adaptive streaming of dynamic point clouds ; and Irene Viola presented a point cloud objective quality assessment using PCA-based descriptors (PointPCA). Another presentation related to point cloud quality assessment was delivered by Marouane Tliba (Université d’Orleans, France), who presented an efficient deep-based graph objective metric.
In addition, Shirin Rafiei (RISE, Sweden) gave a talk on UX and QoE aspects of remote control operations using a laboratory platform, Marta Orduna (Universidad Politécnica de Madrid, Spain) presented her work on comparing ACR, SSDQE, and SSCQE in long duration 360-degree videos, whose results will be used to submit a proposal to extend ITU-T Rec. P.919 for long sequences, and Ali Ak (Nantes Université, France) his work on just noticeable differences to HDR/SDR image/video quality.
Quality Assessment for Computer Vision Applications (QACoViA)
The goal of the QACoViA group is to study the visual quality requirements for computer vision methods, where the “final observer” is an algorithm. Four presentations were delivered in this meeting addressing diverse related topics. In the first one, Mikołaj Leszczuk (AGH University, Poland) presented a method for assessing objective video quality for automatic license plate recognition tasks . Also, Femi Adeyemi-Ejeye (University of Surrey, UK) presented his work related to the assessment of rail 8K-UHD CCTV facing video for the investigation of collisions. The third presentation dealt with the application of facial expression recognition and was delivered by Lucie Lévêque (Nantes Université, France), who compared the robustness of humans and deep neural networks on this task . Finally, Alban Marie (INSA Rennes, France) presented a study video coding for machines through a large-scale evaluation of DNNs robustness to compression artefacts for semantic segmentation .
In relation to the Human Factors for Visual Experiences (HFVE) group, Maria Martini (Kingston University, UK) provided a summary of the status of IEEE recommended practice for the quality assessment of light field imaging. Also, Kjell Brunnström (RISE, Sweden) presented a study related to the perceptual quality of video on simulated low temperatures in LCD vehicle displays.
In addition, a new group was created in this meeting called Emerging Technologies Group (ETG), whose main objective is to address various aspects of multimedia that do not fall under the scope of any of the existing VQEG groups. The topics addressed are not necessarily directly related to “video quality” but can indirectly impact the work addressed as part of VQEG. In particular, two major topics of interest were currently identified: AI-based technologies and greening of streaming and related trends. Nevertheless, the group aims to provide a common platform for people to gather together and discuss new emerging topics, discuss possible collaborations in the form of joint survey papers/whitepapers, funding proposals, etc.
Moreover, it was agreed during the meeting to make the Psycho-Physiological Quality Assessment (PsyPhyQA) group dormant until interest resumes in this effort. Also, it was proposed to move the Implementer’s Guide for Video Quality Metrics (IGVQM) project into the JEG-Hybrid, since their activities are currently closely related. This will be discussed in future group meetings and the final decisions will be announced. Finally, as a reminder, the VQEG GitHub with tools and subjective labs setup is still online and kept updated.
The next VQEG plenary meeting will take place in May 2023 and the location will be announced soon on the VQEG website.
 Maria G. Martini, “On the relationship between SSIM and PSNR for DCT-based compressed images and video: SSIM as content-aware PSNR”, TechRxiv. Preprint. https://doi.org/10.36227/techrxiv.21725390.v1, 2022.
 J. Zhu, P. Le Callet; A. Perrin, S. Sethuraman, K. Rahul, “On The Benefit of Parameter-Driven Approaches for the Modeling and the Prediction of Satisfied User Ratio for Compressed Video”, IEEE International Conference on Image Processing (ICIP), Oct. 2022.
 Margaret H. Pinson, “Why No Reference Metrics for Image and Video Quality Lack Accuracy and Reproducibility”, Frontiers in Signal Processing, Jul. 2022.
 S. Rossi, I. viola, P. Cesar, “Behavioural Analysis in a 6-DoF VR System: Influence of Content, Quality and User Disposition”, Proceedings of the 1st Workshop on Interactive eXtended Reality, Oct. 2022.
 S. Subramanyam, I. Viola, J. Jansen, E. Alexiou, A. Hanjalic, P. Cesar, “Subjective QoE Evaluation of User-Centered Adaptive Streaming of Dynamic Point Clouds”, International Conference on Quality of Multimedia Experience (QoMEX), Sep. 2022.
 M. Leszczuk, L. Janowski, J. Nawała, and A. Boev, “Method for Assessing Objective Video Quality for Automatic License Plate Recognition Tasks”, Communications in Computer and Information Science, Oct. 2022.
 L. Lévêque, F. Villoteau, E. V. B. Sampaio, M. Perreira Da Silva, and P. Le Callet, “Comparing the Robustness of Humans and Deep Neural Networks on Facial Expression Recognition”, Electronics, 11(23), Dec. 2022.
 A. Marie, K. Desnos, L. Morin, and Lu Zhang, “Video Coding for Machines: Large-Scale Evaluation of Deep Neural Networks Robustness to Compression Artifacts for Semantic Segmentation”, IEEE International Workshop on Multimedia Signal Processing (MMSP), Sep. 2022.