Report from ACM IMX 2021 by Lingyuan Li

Although the Covid-19 pandemic has forced international researchers and practitioners to share their research at virtual conferences, ACM Interactive Media Experiences (IMX) 2021 clearly invested significant time and effort to provide all attendees with an accessible, interactive, and vibrant online academic feast. Serving on the Organizing Committee of IMX 2021 as the Student Volunteer Chair as well as a Doctoral Consortium student, I was happy and honoured to take part in the conference, to help support it, and to see how attendees enjoyed and benefited from it. 

I was also delighted to receive the ACM SIGMM Best Social Media Reporter Award which offered me the opportunity to write this report as a summary of my experiences with IMX 2021 (and of course a free ACM SIGMM conference registration!!).

OhYay Platform

IMX 2020 was the first time for the conference to go entirely virtual. In its second year as an entirely virtual conference, IMX 2021 collaborated with OhYay to create a very realistic and immersive experience for the conference attendees. On OhYay, attendees felt like they were in a real conference venue in New York City. There was a reception, lobbies, main hall, showcase rooms, rooftop, pool, and so forth. In addition to the high-fidelity environment, IMX 2021 and the OhYay development team added many interaction features into the platform to help attendees have a more human-centred and engaging experience: for example, attendees were able to “whisper” to each other without others being able to hear; they could send reactions, like applause emoji with sound effects; they could join some social events together, such as lip-sync, jigsaw.

Informative Conference

IMX 2021 contained a high number of inspiring talks, insightful discussions, and quality communication. On Day 1, IMX hosted a series of workshops: XR in Games, Life Improvement in Quality by Ubiquitous Experiences (LIQUE), DataTV and SensoryX. I had a three-hour doctoral consortium (DC) in the morning on Day 1 as well. 8 PhD students presented ongoing dissertation research and had 2 one-on-one sessions with distinguished researchers as mentors! I was so excited to meet people in a ‘real’ virtual space and the OhYay platform also enabled DC attendees to take group pictures in the photo booth. I could not help but Tweet my first-day experience with lots of photos.

My Tweet of DC in IMX 

On Day 2 and Day 3, with artist Sougwen Chung’s amazing keynote “Where does ‘AI’ end and ‘we’ begin?” kicking off the main conference, a set of paper sessions and panel discussions regarding mixed-reality (AR/VR), AI, gaming and inclusive design brought inspiration, new ideas and state-of-the-art research topics to attendees. Admittedly, AR/VR as well as AI technology as the focus of the current development of science and technology, lead the progress of civilization of the times. IMX helped us to see this trend of balance and integration of AI, AR, VR and MR in the future: the downstream of the hyper-reality terminal products dips into various fields, including games, consumer applications, enterprise applications, health care, education and others. With the increase of downstream application scenarios, the market space is expected to further expand. This opens up a broader world for all researchers, designers and practitioners including IMXers to explore how we can put warmth into products delivered by the developing technologies which come with many unknowns and create a need for establishing best practices, standards, and design patterns for as many people as reasonably possible.

My Tweet of the IMX main conference: Enjoyed a great deal of quality discussion and amazing interactive social events.

Every time I tweeted, I picked up representative screenshots, made them into a pretty collage, and gave infectious enthusiasm to the text. That may be my secret of winning the Social Media Award to help disseminate IMX information.

Novelties

Social Events

In addition to the world-leading interactive media research sessions, panels, speakers and showcases presented, IMX 2021 also aimed for some interactive fun for networking and chilling for attendees. There was a virtual elevator that could be seen as an events hub for attendees to select which event they wanted to join. Various social events were provided to enrich breaks in between research sessions: Mukbang, Yoga, Lip Sync, Jigsaw, etc. For example, attendees sometimes needed to collaborate with Jigsaw, which spontaneously enhanced mutual understanding through the interactive collaborative engagement even if IMX was a virtual conference. 

In this sense, IMX 2021 succeeded in its aim to allow attendees to have an “in-person” and immersive experience as much as possible because there were many opportunities for attendees to communicate more deeply, network, and socialize.

Doctoral Consortium

IMX 2021 DC provided an opportunity for 8 PhD students to present, explore and develop our research interests, under the mentorship of a panel of 14 distinguished researchers, including 2 one-on-one sessions. The virtual conference enabled mentors from all over the world to make exchanges views with students without geographical limitations. We were also able to have in-depth communication to obtain valuable instruction on dissertation research in such an immersive environment. Moreover, each student not only gave a presentation at the DC before the main conference but also presented a poster at the conference, enabling wider visibility of our work. 

Doctoral Consortium Reception Room

Accessibility

It is noteworthy that IMX 2021 made accessibility design an integral part of the conference. Except for closed-caption for ready-made videos, IMX 2021 had a captioner to provide an accurate real-time caption for a live discussion. In addition, some attendees were excited to find out that an ASL option was also offered! 

Optional ASL and live caption

IMX also took efforts to make the platform more friendly to screen-reader users. 

Conclusion

In conclusion, IMX 2021 was an excellent example of an engaging, interactive, fun, informative and nice virtual conference. The organizing team clearly not only made significant efforts to represent the diversity in which interactive media is used in our lives but also already presented an amazing show of how interactive the media could be to even benefit our online communication. I look forward to IMX 2022!

MPEG Visual Quality Assessment Advisory Group: Overview and Perspectives

Introduction

The perceived visual quality is of utmost importance in the context of visual media compression, such as 2D, 3D, immersive video, and point clouds. The trade-off between compression efficiency and computational/implementation complexity has a crucial impact on the success of a compression scheme. This specifically holds for the development of visual media compression standards which typically aims at maximum compression efficiency using state-of-the-art coding technology. In MPEG, the subjective and objective assessment of visual quality has always been an integral part of the standards development process. Due to the significant effort of formal subjective evaluations, the standardization process typically relies on such formal tests in the starting phase and for verification while in the development phase objective metrics are used. In the new MPEG structure, established in 2020, a dedicated advisory group has been installed for the purpose of providing, maintaining, and developing visual quality assessment methods suitable for use in the standardization process.

This column lays out the scope and tasks of this advisory group and reports on its first achievements and developments. After a brief overview of the organizational structure, current projects are presented, and initial results are presented.

Organizational Structure

MPEG: A Group of Groups in ISO/IEC JTC 1/SC 29

The Moving Pictures Experts Groups (MPEG) is a standardization group that develops standards for coded representation of digital audio, video, 3D Graphics and genomic data. Since its establishment in 1988, the group has produced standards that enable the industry to offer interoperable devices for an enhanced digital media experience [1]. In its new structure as defined in 2020, MPEG is established as a set of Working Groups (WGs) and Advisory Groups (AGs) in Sub-Committee (SC) 29 “Coding of audio, picture, multimedia and hypermedia information” of the Joint Technical Committee (JTC) 1 of ISO (International Standardization Organization) and IEC (International Electrotechnical Commission). The lists of WGs and AGs in SC 29 are shown in Figure 1. Besides MPEG, SC 29 also includes and JPEG (the Joint Photographic Experts Group, WG 1) as well as an Advisory Group for Chair Support Team and Management (AG 1) and an Advisory Group for JPEG and MPEG Collaboration (AG 4), thereby covering the wide field of media compression and transmission. Within this structure, the focus of AG 5 MPEG Visual Quality Assessment (MPEG VQA) is on interaction and collaboration with the working groups directly working on MPEG visual media compression, including WG 4 (Video Coding), WG 5 (JVET), and WG 7 (3D Graphics).

Figure 1. MPEG Advisory Groups (AGs) and Working Groups (WGs) in ISO/IEC JTC 1/SC 29 [2].

Setting the Field for MPEG VQA: The Terms of Reference

SC 29 has defined Terms of Reference (ToR) for all its WGs and AGs. The scope of AG5 MPEG Visual Quality Assessment is to support needs for quality assessment testing in close coordination with the relevant MPEG Working Groups, dealing with visual quality, with the following activities [2]:

  • to assess the visual quality of new technologies to be considered to begin a new standardization project;
  • to contribute to the definition of Calls for Proposals (CfPs) for new standardization work items;
  • to select and design subjective quality evaluation methodologies and objective quality metrics for the assessment of visual coding technologies, e.g., in the context of a Call for Evidence (CfE) and CfP;
  • to contribute to the selection of test material and coding conditions for a CfP;
  • to define the procedures useful to assess the visual quality of the submissions to a CfP;
  • to design and conduct visual quality tests, process, and analyze the raw data, and make the report of the evaluation results available conclusively;
  • to support in the assessment of the final status of a standard, verifying its performance compared to the existing standard(s);
  • to maintain databases of test material;
  • to recommend guidelines for selection of testing laboratories (verifying their current capabilities);
  • to liaise with ITU and other relevant organizations on the creation of new Quality Assessment standards or the improvement of the existing ones.

Way of Working

Given the fact that MPEG Visual Quality Assessment is an advisory group, and given the above-mentioned ToR, the goal of AG5 is not to produce new standards on its own. Instead, AG5 strives to communicate and collaborate with relevant SDOs in the field, applying existing standards and recommendations and potentially contributing to further development by reporting results and working practices to these groups.

In terms of meetings, AG5 adopts the common MPEG meeting cycle of typically four MPEG AG/WG meetings per year, which -due to the ongoing pandemic situation- so far have all been held online. The meetings are held to review the progress of work, agree on recommendations, and decide on further plans. During the meeting, AG5 closely collaborates with the MPEG WGs and conducts experts viewing sessions in various MPEG standardization activities. The focus of such activities includes the preparation of new standardization projects, the performance verification of completed projects, as well as support of ongoing projects, where frequent subjective evaluation results are required in the decision process. Between meetings, AG5 work is carried out in the context of Ad-hoc Groups (AhGs) which are established from meeting to meeting with well-defined tasks.

Focus Groups

Due to the broad field of ongoing standardization activities, AG5 has established so-called focus groups which cover the relevant fields of development. The focus group structure and the appointed chairs are shown in Figure 2.

Figure 2. MPEG VQA focus groups.

The focus groups are mandated to coordinate with other relevant MPEG groups and other standardization bodies on activities of mutual interest, and to facilitate the formal and informal assessment of the visual media type under their consideration. The focus groups are described as follows:

  • Standard Dynamic Range Video (SDR): This is the ‘classical’ video quality assessment domain. The group strives to support, design, and conduct testing activities on SDR content at any resolution and coding condition, and to maintain existing testing methods and best practice procedures.
  • High Dynamic Range Video (HDR): The focus group on HDR strives to facilitate the assessment of HDR video quality using different devices with combinations of spatial resolution, colour gamut, and dynamic range, and further to maintain and refine methodologies for measuring HDR video quality. A specific focus of the starting phase was on the preparation of the verification tests for Versatile Video Coding (VVC, ISO/IEC 23090-3 / ITU-T H.266).
  • 360° Video: The omnidirectional characteristics of 360° video content have to be taken into account for visual quality assessment. The groups’ focus is on continuing the development of 360° video quality assessment methodologies, including those using head-mounted devices. Like with the focus group on HDR, the verification tests for VVC had priority in the starting phase.
  • Immersive Video (MPEG Immersive Video, MIV): Since MIV allows for movement of the user at six degrees of freedom, the assessment of this type of content bears even more challenges and the variability of the user’s perception of the media has to be factored in. Given the absence of an original reference or ground truth, for the synthetically rendered scene, objective evaluation with conventional objective metrics is a challenge. The focus group strives to develop appropriate subjective expert viewing methods to support the development process of the standard and also evaluates and improve objective metrics in the context of MIV.

Ad hoc Groups

AG5 currently has three AhGs defined which are briefly presented with their mandates below:

  • Quality of immersive visual media (chaired by Christian Timmerer of AAU/Bitmovin, Joel Jung of Tencent, and Aljosa Smolic of Trinity College Dublin): Study Draft Overview of Quality Metrics and Methodologies for Immersive Visual Media (AG 05/N00013) with respect to new updates presented at this meeting; Solicit inputs for subjective evaluation methods and objective metrics for immersive video (e.g., 360, MIV, V-PCC, G-PCC); Organize public online workshop(s) on Quality of Immersive Media: Assessment and Metrics.
  • Learning-based quality metrics for 2D video (chaired by Yan Ye of Alibaba and Mathias Wien of RWTH Aachen University): Compile and maintain a list of video databases suitable and available to be used in AG5’s studies; Compile a list of learning-based quality metrics for 2D video to be studied; Evaluate the correlation between the learning-based quality metrics and subjective quality scores in the databases;
  • Guidelines for subjective visual quality evaluation (chaired by Mathias Wien of RWTH Aachen University, Lu Yu of Zhejiang University and Convenor of MPEG Video Coding (ISO/IEC JTC1 SC29/WG4), and Joel Jung of Tencent): Prepare the third draft of the Guidelines for Verification Testing of Visual Media Specifications; Prepare the second draft of the Guidelines for remote experts viewing test methods for use in the context of Ad-hoc Groups, and Core or Exploration Experiments.

AG 5 First Achievements

Reports and Guidelines

The results of the work of the AhGs are aggregated in AG5 output documents which are public (or will become public soon) in order to allow for feedback also from outside of the MPEG community.

The AhG on “Quality for Immersive Visual Media” maintains a report “Overview of Quality Metrics and Methodologies for Immersive Visual Media” [3] which documents the state-of-the-art in the field and shall serve as a reference for MPEG working groups in their work on compression standards in this domain. The AhG further organizes a public workshop on “Quality of Immersive Media: Assessment and Metrics” which takes place in an online form at the beginning of October 2021 [4]. The scope of this workshop is to raise awareness about MPEG efforts in the context of quality of immersive visual media and to invite experts outside of MPEG to present new techniques relevant to the scope of this workshop.

The AhG on “Guidelines for Subjective Visual Quality Evaluation” currently develops two guideline documents supporting the MPEG standardization work. The “Guidelines for Verification Testing of Visual Media Specifications” [5] define the process of assessing the performance of a completed standard after its publication. The concept of verification testing has already been established MPEG working practice for its media compression standards since the 1990ties. The document is intended to formalize the process, describe the steps and conditions for the verification tests, and set the requirements to meet MPEG procedural quality expectations.

The AhG has further released a first draft of “Guidelines for Remote Experts Viewing Sessions” with the intention to establish a formalized procedure for ad-hoc generation subjective test results as input to the standards development process [6]. This activity has been driven by the ongoing pandemic situation which forced MPEG to continue its work in virtual online meetings since early 2020. The procedure for remote experts viewing is intended to be applied during the (online) meeting phase or in the AhG phase and to provide measurable and reproducible subjective results in order to be input to the decision-making process in the project under consideration.

Verification Testing

With Essential Video Coding (EVC) [7], Low Complexity Enhancement Video Coding (LCEVC) [8] of ISO/IEC, and the joint coding standard Versatile Video Coding (VVC) of ISO/IEC and ITU-T [9][10], a significant number of new video coding standards has been recently released. Since its first meeting in October 2020, AG5 has been engaged in the preparation and conduction of verification tests for these video coding specifications. Further verification tests for MPEG Immersive Video (MIV) and Video-based Point Cloud Compression (V-PCC) [11] are under preparation and more are to come. Results of the verification test activities which have been completed in the first year of AG5 are summarized in the following subsections. All reported results have been achieved by formal subjective assessments according to established assessment protocols [12][13] and performed by qualified test laboratories. The bitstreams were generated with reference software encoders of the specification under consideration using established encoder configurations with comparable settings for both, the reference and the evaluated coding schemes. It has to be noted that all testing had to be done under the constrained conditions of the ongoing pandemic situation which induced an additional challenge for the test laboratories in charge.

MPEG-5 Part 1: Essential Video Coding (EVC)

The EVC standard was developed with the goal to provide a royalty-free Baseline profile and a Main profile with higher compression efficiency compared to High-Efficiency Video Coding (HEVC) [15][16][17]. Verification tests were conducted for Standard Dynamic Range (SDR) and high dynamic range (HDR, BT.2100 PQ) video content at both, HD (1920×1080 pixels) and UHD (3840×2160 pixels) resolution. The tests revealed around 40% bitrate savings at a comparable visual quality for the Main profile when compared to HEVC, and around 36% bitrate saving for the Baseline profile when compared to Advanced Video Coding (AVC) [18][19], both for SDR content [20]. For HDR PQ content, the Main profile provided around 35% bitrate savings for both resolutions [21].

MPEG-5 Part 2: Low-Complexity Enhancement Video Coding (LCEVC)

The LCEVC standard follows a layered approach where an LCEVC enhancement layer is added to a lower resolution base layer of an existing codec in order to achieve the full resolution video [22]. Since the base layer codec operates at a lower resolution and the separate enhancement layer decoding process is relatively lightweight, the computational complexity of the decoding process is typically lower compared to decoding of the full resolution with the base layer codec. The addition of the enhancement layer would typically be provided on top of the established base layer decoder implementation by an additional decoding entity, e.g., in a browser.

For verification testing, LCEVC was evaluated using AVC, HEVC, EVC, and VVC base layer bitstreams at half resolution, and comparing the performance to the respective schemes with full resolution coding as well half-resolution coding with a simple upsampling tool. For UHD resolution, the bitrate savings for LCEVC at comparable visual quality were at 46% when compared to full resolution AVC and 31% when compared to full resolution HEVC. The comparison to the more recent and more efficient EVC and VVC coding schemes led to partially overlapping confidence intervals of the subjective scores of the test subjects. The curves still revealed some benefits for the application of LCEVC. The gains compared to half-resolution coding with simple upsampling provided approximately 28%, 34%, 38%, and 33% bitrate savings at comparable visual quality, demonstrating the benefit of LCEVC enhancement layer coding compared to straight-forward plain upsampling [23].

MPEG-I Part 3 / ITU-T H.266: Versatile Video Coding (VVC)

VVC is the most recent video coding standard in the historical line of joint specifications of ISO/IEC and ITU-T, such as AVC and HEVC. The development focus for VVC was on compression efficiency improvement at a moderate increase of decode complexity as well as the versatility of the design [24][25]. Versatility features include tools designed to address HDR, WCG, resolution-adaptive multi-rate video streaming services, 360-degree immersive video, bitstream extraction and merging, temporal scalability, gradual decoding refresh, and multilayer coding to deliver layered video content to support application features such as multiview, alpha maps, depth maps, and spatial and quality scalability.

A series of verification tests have been conducted covering SDR UHD and HD, HDR PQ and HLG, as well as 360° video contents [26][27][28]. An early open-source encoder (VVenC, [14]) was additionally assessed in some categories. For SDR coding, both, the VVC reference software (VTM) and the open-source VVenC were evaluated against the HEVC reference software (HM). The results revealed bit rate savings of around 46% (SDR UHD, VTM and VVenC), 50% (SDR HD, VTM and VVenC), 49% (HDR UHD, PQ and HLG), 52%, and 50-56% (360° with different projection formats) at a similar visual quality compared to HEVC. In Figure 3, pooled MOS (Mean Opinion Score) over bit rate points for the mentioned categories are provided. The MOS values range from 10 (imperceptible impairments) down to 0 (everywhere severely annoying impairments). Pooling was done by computing the geometric mean of the bitrates and the arithmetic mean of the MOS scores across the test sequences of each test category. The results reveal a consistent benefit of VVC over its predecessor HEVC in terms of visual quality over the required bitrate.

Figure 3. Pooled MOS over bitrate plots of the VVC verification tests for the SDR UHD, SDR HD, HDR HLG, and 360° video test categories. Curves cited from [26][27][28].

Summary

This column presented an overview of the organizational structure and the activities of the Advisory Group on MPEG Visual Quality Assessment, ISO/IEC JTC 1/SC 29/AG 5, which has been formed about one year ago. The work items of AG5 include the application, documentation, evaluation, and improvement of objective quality metrics and subjective quality assessment procedures. In its first year of existence, the group has produced an overview on immersive quality metrics, draft guidelines for verification tests and for remote experts viewing sessions as well as reports of formal subjective quality assessments for the verification tests of EVC, LCEVC, and VVC. The work of the group will continue towards studying and developing quality metrics suitable for the assessment tasks emerging by the development of the various MPEG visual media coding standards and towards subjective quality evaluation in upcoming and future verification tests and new standardization projects.

References

[1] MPEG website, https://www.mpegstandards.org/.
[2] ISO/IEC JTC1 SC29, “Terms of Reference of SC 29/WGs and AGs,” Doc. SC29N19020, July 2020.
[3] ISO/IEC JTC1 SC29/AG5 MPEG VQA, “Draft Overview of Quality Metrics and Methodologies for Immersive Visual Media (v2)”, doc. AG5N13, 2nd meeting: January 2021.
[4] MPEG AG 5 Workshop on Quality of Immersive Media: Assessment and Metrics, https://multimediacommunication.blogspot.com/2021/08/mpeg-ag-5-workshop-on-quality-of.html, October 5th, 2021.
[5] ISO/IEC JTC1 SC29/AG5 MPEG VQA, “Guidelines for Verification Testing of Visual Media Specifications (draft 2)”, doc. AG5N30, 4th meeting: July 2021.
[6] ISO/IEC JTC1 SC29/AG5 MPEG VQA, “Guidelines for remote experts viewing sessions (draft 1)”, doc. AG5N31, 4th meeting: July 2021.
[7] ISO/IEC 23094-1:2020, “Information technology — General video coding — Part 1: Essential video coding”, October 2020.
[8] ISO/IEC 23094-2, “Information technology – General video coding — Part 2: Low complexity enhancement video coding”, September 2021.
[9] ISO/IEC 23090-3:2021, “Information technology — Coded representation of immersive media — Part 3: Versatile video coding”, February 2021.
[10] ITU-T H.266, “Versatile Video Coding“, August 2020. https://www.itu.int/rec/recommendation.asp?lang=en&parent=T-REC-H.266-202008-I.
[11] ISO/IEC 23090-5:2021, “Information technology — Coded representation of immersive media — Part 5: Visual volumetric video-based coding (V3C) and video-based point cloud compression (V-PCC)”, June 2021.
[12] ITU-T P.910 (2008), Subjective video quality assessment methods for multimedia applications.
[13] ITU-R BT.500-14 (2019), Methodologies for the subjective assessment of the quality of television images.
[14] Fraunhofer HHI VVenC software repository. [Online]. Available: https://github.com/fraunhoferhhi/vvenc.
[15] K. Choi, J. Chen, D. Rusanovskyy, K.-P. Choi and E. S. Jang, “An overview of the MPEG-5 essential video coding standard [standards in a nutshell]”, IEEE Signal Process. Mag., vol. 37, no. 3, pp. 160-167, May 2020.
[16] ISO/IEC 23008-2:2020, “Information technology — High efficiency coding and media delivery in heterogeneous environments — Part 2: High efficiency video coding”, August 2020.
[17] ITU-T H.265, “High Efficiency Video Coding”, August 2021.
[18] ISO/IEC 14496-10:2020, “Information technology — Coding of audio-visual objects — Part 10: Advanced video coding”, December 2020.
[19] ITU-T H.264, “Advanced Video Coding”, August 2021.
[20] ISO/IEC JTC1 SC29/WG4, “Report on Essential Video Coding compression performance verification testing for SDR Content”, doc WG4N47, 2nd meeting: January 2021.
[21] ISO/IEC JTC1 SC29/WG4, “Report on Essential Video Coding compression performance verification testing for HDR/WCG content”, doc WG4N30, 1st meeting: October 2020.
[22] G. Meardi et al., “MPEG-5—Part 2: Low complexity enhancement video coding (LCEVC): Overview and performance evaluation”, Proc. SPIE, vol. 11510, pp. 238-257, Aug. 2020.
[23] ISO/IEC JTC1 SC29/WG4, “Verification Test Report on the Compression Performance of Low Complexity Enhancement Video Coding”, doc. WG4N76, 3rd meeting: April 2020.
[24] Benjamin Bross, Jianle Chen, Jens-Rainer Ohm, Gary J. Sullivan, and Ye-Kui Wang, “Developments in International Video Coding Standardization After AVC, With an Overview of Versatile Video Coding (VVC)”, Proceedings of the IEEE, Vol. 109, Issue 9, pp. 1463–1493, doi 10.1109/JPROC.2020.3043399, Sept. 2021 (open access publication), available at https://ieeexplore.ieee.org/document/9328514.
[25] Benjamin Bross, Ye-Kui Wang, Yan Ye, Shan Liu, Gary J. Sullivan, and Jens-Rainer Ohm, “Overview of the Versatile Video Coding (VVC) Standard and its Applications”, IEEE Trans. Circuits & Systs. for Video Technol. (open access publication), available online at https://ieeexplore.ieee.org/document/9395142.
[26] Mathias Wien and Vittorio Baroncini, “VVC Verification Test Report for Ultra High Definition (UHD) Standard Dynamic Range (SDR) Video Content”, doc. JVET-T2020 of ITU-T/ISO/IEC Joint Video Experts Team (JVET), 20th meeting: October 2020.
[27] Mathias Wien and Vittorio Baroncini, “VVC Verification Test Report for High Definition (HD) and 360° Standard Dynamic Range (SDR) Video Content”, doc. JVET-V2020 of ITU-T/ISO/IEC Joint Video Experts Team (JVET), 22nd meeting: April 2021.
[28] Mathias Wien and Vittorio Baroncini, “VVC verification test report for high dynamic range video content”, doc. JVET-W2020 of ITU-T/ISO/IEC Joint Video Experts Team (JVET), 23rd meeting: July 2021.

Multidisciplinary column: the importance of talking to a 12-year old

In 2018, while on a research visit to Bordeaux, I felt it would be good to connect more closely to the local community. As a consequence, colleagues convinced me to join the Femmes & Sciences movement, in which women researchers in STEM proactively did local outreach.

My French was conversational, though not stellar. But I thought it hopefully should be good enough to converse with young teenagers. Furthermore, as for ‘local community’, it would be a nice idea to both get to know colleagues and the culture of the local schools. So there I went, speaking at a countryside school in one of the many wine regions, and at a secondary school in Bordeaux where students would not trivially think of STEM university careers.

It was an amazing and enlightening experience. As soon as I started to talk about search engines, recommender systems, music and video services, a spark really ignited in the students. They knew these, and they used them daily!

But it only was because of me mentioning it, that they started realizing there was computer science technology behind all these services. Before, they had no clue.

And I think this is a real problem, that we as a community severely undervalue.

In my own family, my father (electrical engineering), sister (civil engineering & geomatics) and I (computer science) studied to become engineers. For the rest of my family, this meant we were ‘the technical people’, getting called in when computers were slow, cell phones were updated and printers started malfunctioning. This especially happened to my father and me, as we ‘were good with computers, since that was our profession’.

But I had not studied to fix printers. And, as I joked during university open days to prospective students, my sister never got asked to go fix the kitchen sink, even though she had been taught about water management.

It always has been striking to me how malfunctioning hardware and software were the first associations that laypeople outside of our field seemed to have with our work. Today, this is broadening to fears of hacking, and on the less negative side, (overblown?) hopes in AI and cryptocurrency. In all these cases, the technology is something alien, something that ‘normal’ humans do not understand and grasp well.

Yet at the same time, the technologies we build affect everyone’s lives, increasingly so. Frequently, they silently work in the back, and we indeed only visibly notice them if something goes wrong. But then, rather strange associations and dialogues emerge.

Recently, I became a member of the national Young Academy, a body of earlier-career faculty across disciplines in The Netherlands, playing a public opinion-making role on academic culture, the image of academia and its findings, and associated policy-making. Through this role, and with my background in search and recommendation, I am increasingly being invited into committees, workshops and other forms of public appearances, that involve policy-makers and laypeople concerned with the impact of AI technologies (especially: possible exclusion of humans, as a consequence of the use of AI technologies).

In these activities, it has again been striking to me how little common vocabulary is present, and how questions thus get formulated awkwardly. More than once, I get asked ‘what the algorithm exactly is doing’, when my discussion partners actually refer to broader decision-making processes, where problems may occur across the pipeline, also already before any algorithm would be deployed.

When I try to explain that much of the applications of interest focus on prioritization with a cutoff within a larger collection, and I ask how my discussion partners would prioritize, I get blank stares if I keep this story at the current, general, abstract level that would come naturally to me as a computer scientist. If I’m unlucky, I may even get an answer back that my discussion partners don’t want to take a stance themselves, as it is ‘difficult and subjective’ matter, but ‘surely AI can do this better than we humans?’. Now that will form a problem if we will frame the problem in a supervised learning setup, without a sense of solid ground truth or criteria to optimize for.

However, going through simple, concrete examples ‘close to home’ does seem to help. Here, I really benefited from the experience I had learnt while in Bordeaux and beyond, especially in setups where I had to work with children.

Try to explain concepts of information retrieval and data modelling in a non-native tongue to a 12-year old, and you are forced to ask simple questions, that will give insight into these children’s own world views and contexts. It will give them building blocks they recognize and can build on.

Working in music and multimedia has greatly helped me here; as said before, everyone is a heavy daily user of music and multimedia services, and thus (without explicitly knowing) actually has some world view ready on preferences, priorities and ways to navigate larger information collections. This will greatly help as a discussion starter, with the discussion elements remaining tangible for everyone.

I would argue that working on a better public understanding of our work is among the most societally impactful roles that we, as researchers in the field, can play. Our discussion partners are stakeholders who don’t realize they are stakeholders. And of course, in the case of children, they may at the same time be the future technologists, who in the future will build forth on our work.

It takes serious time investment and a lot of practice to get this right. I have always been puzzled at how this typically meant this would be considered too much of a time sink, and not our prime responsibility as academics. But who else would otherwise take this up?

And if I think of how much time I have been encouraged to sink into endlessly rewriting grant proposals or papers at the micro-level, just to hopefully please reviewers, something does not feel right. Any acceptances following this have arguably been good for my career. But I am not quite convinced this has been more meaningful use of the public money my contract is funded from.

Or, in a more positive interpretation: in our community, we actually care about communicating well, and are clearly willing to invest in it. But so far, we really have been focusing our attention inward, while there is a lot to gain when we’d rather look outward.

So for those who would be interested in engaging more with those outsides of our field: please do. Outreach is much more than cute PR. And with the applications that we work on being so close to people’s daily lives, we in music/multimedia hold some very important keys, and really should learn the perspectives of our end users.

So let’s use those keys, and finally, get some doors opened that have remained shut for too long.

Editor Biographies

Cynthia_Liem_2017

Dr. Cynthia C. S. Liem is an Associate Professor in the Multimedia Computing Group of Delft University of Technology, The Netherlands, and pianist of the Magma Duo. Her research interests focus on making people discover new interests and content which would not trivially be retrieved, and assessing questions of validation and validity, especially in the context of music and multimedia search and recommendation. She initiated and co-coordinated the European research projects PHENICX (2013-2016) and TROMPA (2018-2021), focusing on technological enrichment of digital musical heritage, and gained industrial experience at Bell Labs Netherlands, Philips Research and Google. She was a recipient of the Lucent Global Science and Google Anita Borg Europe Memorial scholarships, the Google European Doctoral Fellowship 2010 in Multimedia, a finalist of the New Scientist Science Talent Award 2016 for young scientists committed to public outreach, and is a member of the Dutch national Young Academy.

jochen_huber

Dr. Jochen Huber is Professor of Computer Science at Furtwangen University, Germany. Previously, he was a Senior User Experience Researcher with Synaptics and an SUTD-MIT postdoctoral fellow in the Fluid Interfaces Group at MIT Media Lab and the Augmented Human Lab at Singapore University of Technology and Design. He holds a Ph.D. in Computer Science and degrees in both Mathematics (Dipl.-Math.) and Computer Science (Dipl.-Inform.), all from Technische Universität Darmstadt, Germany. Jochen’s work is situated at the intersection of Human-Computer Interaction and Human Augmentation. He designs, implements and studies novel input technology in the areas of mobile, tangible & non-visual interaction, automotive UX and assistive augmentation. He has co-authored over 60 academic publications and regularly serves as program committee member in premier HCI and multimedia conferences. He was program co-chair of ACM TVX 2016 and Augmented Human 2015 and chaired tracks of ACM Multimedia, ACM Creativity and Cognition and ACM International Conference on Interface Surfaces and Spaces, as well as numerous workshops at ACM CHI and IUI. Further information can be found on his personal homepage: http://jochenhuber.com

JPEG Column: 92nd JPEG Meeting

JPEG Committee explores NFT standardisation needs

The 92nd JPEG meeting was held online from 7 to 13 July 2021. This meeting has consolidated JPEG’s exploration on standardisation needs related to Non-Fungible Tokens (NFTs). Recently, there has been a growing interest in the use of NFTs in many applications, notably in the trade of digital art and collectables.

Other notable results of the 92nd JPEG meeting have been the release of an update to the Call for Proposals on JPEG Pleno Holography and an initiative to revisit opportunities for standardisation of image quality assessment methodologies and metrics.

The 92nd JPEG meeting had the following highlights:

  • JPEG NFT exploration;
  • JPEG Fake Media defines context, use cases and requirements;
  • JPEG Pleno Holography call for proposals;
  • JPEG AI prepare Call for Proposals;
  • JPEG AIC explores new quality models;
  • JPEG Systems;
  • JPEG XS;
  • JPEG XL;
  • JPEG DNA.

The following provides an overview of the major achievements of the 92nd JPEG meeting.

JPEG NFT exploration

Recently, Non-Fungible Tokens (NFTs) have garnered considerable interest. Numerous digital assets linked with NFTs are either encoded in existing JPEG formats or can be represented in JPEG-developed current and forthcoming representations. Additionally, various trust and security concerns have been raised about NFTs and the digital assets on which they rely. To better understand user requirements for media formats, the JPEG Committee has launched the JPEG NFT exploration initiative. The mission of JPEG NFT is to provide effective specifications that enable various applications that rely on NFTs applied to media assets. A JPEG NFT standard shall be secure, trustworthy, and eco-friendly, enabling an interoperable ecosystem based on NFTs within or across applications. The committee strives to engage stakeholders from diverse backgrounds, including the technical, legal, artistic, and end-user communities, to establish use cases and requirements. In this context, the first JPEG NFT Workshop was held on July 1st, 2021. The workshop’s presentations and video footage are now accessible on the JPEG website, and a second workshop will be held in the near future. JPEG encourages interested parties to frequently visit its website for the most up-to-date information and to subscribe to the mailing list of the JPEG NFT Ad Hoc Group (AhG) in order to participate in this effort.

JPEG Fake Media

The scope of the JPEG Fake Media exploration is to assess standardisation needs to facilitate secure and reliable annotation of media asset creation and modifications in good-faith usage scenarios as well as in those with malicious intent. At the 92nd meeting, the JPEG Committee released an updated version of the “JPEG Fake Media Context, Use Cases and Requirements” document. This new version includes an improved and extended set of requirements covering three main categories: media creation and modification descriptions, metadata embedding & referencing and authenticity verification. In addition, the document contains several improvements including an extended set of definitions covering key terminologies. The JPEG Committee welcomes feedback to the document and invites interested experts to join the JPEG Fake Media AhG mailing list to get involved in the discussion.

JPEG Pleno

Currently, a Call for Proposals is open for JPEG Pleno Holography, which is the first standardisation effort aspiring to provide a versatile solution for efficient compression of holograms for a wide range of applications such as holographic microscopy, tomography, interferometry, printing, and display, and their associated hologram types. Key desired functionalities include support for both lossy and lossless coding, scalability, random access, and integration within the JPEG Pleno system architecture, with the goal of supporting a royalty-free baseline. In support of this Call for Proposals, a Common Test Conditions document and accompanying software have been released, enabling elaborate stress testing from the rate-distortion, functionality and visual rendering quality perspectives. For the latter, numerical reconstruction software has been released enabling viewport rendering from holographic data. References to software and documentation can be found on the JPEG website.

JPEG Pleno Point Cloud continues to progress towards a Call for Proposals on learning-based point cloud coding solutions with the release at the 92nd JPEG meeting of an updated Use Cases and Requirements document. This document details how the JPEG Committee envisions learning-based point cloud coding solutions meeting the requirements of rapidly emerging use cases in this field. This document continues the focus on solutions supporting scalability and random access while detailing new requirements for 3D processing and computer vision tasks performed in the compressed domain to support emerging applications such as autonomous driving and robotics.

JPEG AI

JPEG AI scope is the creation of a learning-based image coding standard offering a single-stream, compact compressed domain representation, targeting both human visualisation with significant compression efficiency improvement over image coding standards in common use at equivalent subjective quality, and effective performance for image processing and computer vision tasks. At the 92nd JPEG meeting, several activities were carried out towards the launch of the final JPEG AI Call for Proposals. This has included improvements of the training and test conditions for learning-based image coding, especially in the areas of the JPEG AI training dataset, target bitrates, computation of quality metrics, subjective quality evaluation, and complexity assessment. A software package called the JPEG AI objective quality assessment framework, with a reference implementation of all objective quality metrics, has been made available. Moreover, the results of the JPEG AI exploration experiments for image processing and computer vision tasks defined at the previous 91st JPEG meeting were presented and discussed, including their impact on Common Test Conditions.

Moreover, the JPEG AI Use Cases and Requirements were refined with two new core requirements regarding reconstruction reproducibility and hardware platform independence. The second draft of the Call for Proposals was produced and the timeline of the JPEG AI work item was revised. It was decided that the final Call for Proposals will be issued as an outcome of the 94th JPEG Meeting. The deadline for expression of interest and registration is 5 February 2022 and the submission of bitstreams and decoded images for the test dataset are due on 30 April 2022.

JPEG AIC

Image quality assessment remains an essential component in the development of image coding technologies. A new activity has been initiated in the JPEG AIC framework to study the assessment of image coding quality, with particular attention to crowd-sourced subjective evaluation methodologies and image coding at fidelity targets relevant for end-user image delivery on the web and consumer-grade photo archival.

JPEG Systems

JUMBF (ISO/IEC 19566-5 AMD1) and JPEG 360 (ISO/IEC 19566-6 AMD1) are now published standards available through ISO. A request to create the second amendment of JUMBF (ISO/IEC 19566-5) has been produced; this amendment will further extend the functionality to cover use cases and requirements under development in the JPEG Fake Media exploration initiative. The Systems software efforts are progressing on the development of a file parser for most JPEG standards and will include support for metadata within JUMBF boxes. Interested parties are invited to subscribe to the mailing list of the JPEG Systems AhG in order to monitor and contribute to JPEG Systems activities.

JPEG XS

JPEG XS aims at the standardization of a visually lossless low-latency and lightweight compression that can be used as a mezzanine codec in various markets. With the second editions of Part 1 (core coding system), Part 2 (profiles and buffer models), and Part 3 (transport and container formats) under ballot to become International Standards, the work during this JPEG meeting went into the second edition of Part 4 (Conformance Testing) and Part 5 (Reference Software). The second edition primarily brings new coding and signalling capabilities to support raw Bayer sensor content, mathematically lossless coding of images with up to 12 bits per colour component sample, and 4:2:0-sampled image content. In addition, the JPEG Committee continued its initial exploration to study potential future improvements to JPEG XS, while still honouring its low-complexity and low-latency requirements. Among such improvements are better support for high dynamic range (HDR), better support for raw Bayer sensor content, and overall improved compression efficiency. The compression efficiency work also targets improved handling of computer-screen content and artificially-generated rendered content.

JPEG XL

JPEG XL aims at standardization for image coding that offers high compression efficiency, along with features desirable for web distribution and efficient compression of high-quality images. JPEG XL Part 3 (Conformance testing) has been promoted to the Committee Draft stage of the ISO/IEC approval process. New core experiments were defined to investigate hardware-based coding, in particular including fixed-point implementations. With preliminary support in major web browsers, image viewing and manipulation libraries and tools, JPEG XL is ready for wide-scale adoption.

JPEG DNA

The JPEG Committee has continued its exploration of the coding of images in quaternary representations, as is particularly suitable for DNA storage. Two new use cases were identified as well as the sequencing noise models and simulators to use for DNA digital storage. There was a successful presentation of the fourth workshop by the stakeholders, and a new version of the JPEG DNA overview document was issued and is now publicly available. It was decided to continue this exploration by organising the fifth workshop and conducting further outreach to stakeholders, as well as to continue improving the JPEG DNA overview document. Moreover, it was also decided to produce software to simulate an end-to-end image storage pipeline using DNA storage for future exploration experiments. Interested parties are invited to consider joining the effort by registering to the mailing list of JPEG DNA.

Final Quote

“The JPEG Committee is considering standardisation needs for timely and effective specifications that can best support the use of NFTs in applications where media assets can be represented with JPEG formats.” said Prof. Touradj Ebrahimi, the Convenor of the JPEG Committee.

Upcoming JPEG meetings are planned as follows:

  • No 93, to be held online during 18-22 October 2021.
  • No 94, to be held online during 17-21 January 2022.

Dataset Column: Overview, Scope and Call for Contributions

Overview and Scope

The Dataset Column (https://records.sigmm.org/open-science/datasets/) of ACM SIGMM Records provides timely updates on the developments in the domain of publicly available multimedia datasets as enabling tools for reproducible research in numerous related areas. It is intended as a platform for further dissemination of useful information on multimedia datasets and studies of datasets covering various domains, published in peer-reviewed journals, conference proceedings, dissertations, or as results of applied research in industry.

The aim of the Dataset Column is therefore not to substitute already established platforms for disseminating multimedia datasets, e.g., Qualinet Databases (https://qualinet.github.io/databases/) [2], Multimedia Evaluation Benchmark (https://multimediaeval.github.io/), but promote such platforms and particularly interesting datasets and benchmarking challenges associated with them. Multimedia Evaluation Benchmark, MediaEval 2021, registration is now open (https://multimediaeval.github.io). This year’s MediaEval features a wide variety of tasks and datasets tackling a large number of domains, including video privacy, social media data analysis and understanding, news items analysis, medicine and wellbeing, affective and subjective content analysis, and game and sports associated media.

The Column will also continue reporting of contributions presented within Dataset Tracks at relevant conferences, e.g., ACM Multimedia (MM), ACM Multimedia Systems (MMSys), International Conference on Quality of Multimedia Experience (QoMEX), International Conference on Multimedia Modeling (MMM).

Dataset Column in the SIGMM Records

Previously published Dataset Columns are listed below in chronological order.

Call for Contributions

Those who have created and even previously published elsewhere a dataset, benchmarking initiative or studies of datasets relevant to the multimedia community are very welcome to submit their contribution to the ACM SIGMM Records Dataset Column. Examples of these are the accepted datasets to the open dataset and software track of the ACM MMSys 2021 conference or the datasets presented at QoMEX 2021 conference. Please contact one of the editors responsible for the respective area, Mihai Gabriel Constantin (mihai.constantin84@upb.ro), Karel Fliegel (fliegek@fel.cvut.cz), and Maria Torres Vega (maria.torresvega@ugent.be) to report your contribution.

Column Editors

Since September 2021, the Dataset Column is edited by Mihai Gabriel Constantin, Karel Fliegel, and Maria Torres Vega. Current editors appreciate the work of the previous team, Martha Larson, Bart Thomee and all other contributors, and will continue and further develop this dissemination platform.

The general scope of the Dataset Column is reviewed above, with the more specific areas of the editors listed below:

  • Mihai Gabriel Constantin will be responsible for the datasets related to multimedia analysis, understanding, retrieval and exploration,
  • Karel Fliegel for the datasets with subjective annotations related to Quality of Experience (QoE) [1] research,
  • Maria Torres Vega for the datasets related to immersive multimedia systems, networked QoE and cognitive network management.

Mihai Gabriel Constantin is a researcher at the AI Multimedia Lab, University Politehnica of Bucharest, Romania, and got his PhD at the Faculty of Electronics, Telecommunications, and Information Technology at the same university, with the topic “Automatic Analysis of the Visual Impact of Multimedia Data”. He has authored over 25 scientific papers in international conferences and high impact journals, with an emphasis on the prediction of the subjective impact of multimedia items on human viewers and deep ensembles. He participated as researcher in more than 10 research projects, and is a member of program committees and reviewer for several workshops, conferences and journals. He is also an active member of the multimedia processing community, being part of the MediaEval benchmarking initiative organization team, and leading or co-organizing several tasks during MediaEval that include Predicting Media Memorability [3] and Recommending Movies Using Content [4], as well as publishing several papers that analyze the data, annotations, participant features, methods, and observed best practices for MediaEval tasks and datasets [5]. More details can be found on his webpage: https://gconstantin.aimultimedialab.ro/.

Karel Fliegel received M.Sc. (Ing.) in 2004 (electrical engineering and audiovisual technology) and his Ph.D. in 2011 (research on modeling of visual perception of image impairment features) both from the Czech Technical University in Prague, Faculty of Electrical Engineering (CTU FEE), Czech Republic. He is an assistant professor at Multimedia Technology Group of CTU FEE. His research interests include multimedia technology, image processing, image and video compression, subjective and objective image quality assessment, Quality of Experience, HVS modeling, and imaging photonics. He has been a member of research teams within various projects especially in the area of visual information processing. He has participated in COST ICT Actions IC1003 Qualinet and IC1105 3D-ConTourNet, responsible for development of Qualinet Databases [2] (https://qualinet.github.io/databases/) relevant especially to QoE research.

Maria Torres Vega is an FWO (Research Foundation Flanders) Senior Postdoctoral fellow working at the multimedia delivery cluster of the IDLab group of the Ghent University (UGent) currently working on the perception of immersive multimedia applications. She received her M.Sc. degree in Telecommunication Engineering from the Polytechnic University of Madrid, Spain, in 2009. Between 2009 and 2013 she worked as a software and test engineer in Germany with focus on Embedded Systems and Signal Processing. In October 2013, she decided to go back to academia and started her PhD at the Eindhoven University of Technology (Eindhoven, The Netherlands), where she researched on the impact of beam-steered optical wireless networks on the users’ perception of services. This work awarded her PhD in Electrical Engineering in September 2017. In her years in academia (since October 2013), she has authored more than 40 publications, including three best paper awards. Furthermore, she serves as reviewer to a plethora of journals and conferences. In 2020 she served as general chair of the 4th Quality of Experience Management workshop, as tutorial chair of the 2020 Network Softwarization conference (NetSoft), and as demo chair of the Quality of Multimedia Experience conference (QoMex 2020). In 2021, she served as Technical Program Committee (TPC) chair of the 2021 Quality of Multimedia Experience conference (QoMex 2021).

References

MPEG Column: 135th MPEG Meeting (virtual/online)

The original blog post can be found at the Bitmovin Techblog and has been modified/updated here to focus on and highlight research aspects.

The 135th MPEG meeting was once again held as an online meeting, and the official press release can be found here and comprises the following items:

  • MPEG Video Coding promotes MPEG Immersive Video (MIV) to the FDIS stage
  • Verification tests for more application cases of Versatile Video Coding (VVC)
  • MPEG Systems reaches first milestone for Video Decoding Interface for Immersive Media
  • MPEG Systems further enhances the extensibility and flexibility of Network-based Media Processing
  • MPEG Systems completes support of Versatile Video Coding and Essential Video Coding in High Efficiency Image File Format
  • Two MPEG White Papers:
    • Versatile Video Coding (VVC)
    • MPEG-G and its application of regulation and privacy

In this column, I’d like to focus on MIV and VVC including systems-related aspects as well as a brief update about DASH (as usual).

MPEG Immersive Video (MIV)

At the 135th MPEG meeting, MPEG Video Coding has promoted the MPEG Immersive Video (MIV) standard to the Final Draft International Standard (FDIS) stage. MIV was developed to support compression of immersive video content in which multiple real or virtual cameras capture a real or virtual 3D scene. The standard enables storage and distribution of immersive video content over existing and future networks for playback with 6 Degrees of Freedom (6DoF) of view position and orientation.

From a technical point of view, MIV is a flexible standard for multiview video with depth (MVD) that leverages the strong hardware support for commonly used video codecs to code volumetric video. The actual views may choose from three projection formats: (i) equirectangular, (ii) perspective, or (iii) orthographic. By packing and pruning views, MIV can achieve bit rates around 25 Mb/s and a pixel rate equivalent to HEVC Level 5.2.

The MIV standard is designed as a set of extensions and profile restrictions for the Visual Volumetric Video-based Coding (V3C) standard (ISO/IEC 23090-5). The main body of this standard is shared between MIV and the Video-based Point Cloud Coding (V-PCC) standard (ISO/IEC 23090-5 Annex H). It may potentially be used by other MPEG-I volumetric codecs under development. The carriage of MIV is specified through the Carriage of V3C Data standard (ISO/IEC 23090-10).

The test model and objective metrics are publicly available at https://gitlab.com/mpeg-i-visual.

At the same time, MPEG Systems has begun developing the Video Decoding Interface for Immersive Media (VDI) standard (ISO/IEC 23090-13) for a video decoders’ input and output interfaces to provide more flexible use of the video decoder resources for such applications. At the 135th MPEG meeting, MPEG Systems has reached the first formal milestone of developing the ISO/IEC 23090-13 standard by promoting the text to Committee Draft ballot status. The VDI standard allows for dynamic adaptation of video bitstreams to provide the decoded output pictures in such a way so that the number of actual video decoders can be smaller than the number of the elementary video streams to be decoded. In other cases, virtual instances of video decoders can be associated with the portions of elementary streams required to be decoded. With this standard, the resource requirements of a platform running multiple virtual video decoder instances can be further optimized by considering the specific decoded video regions that are to be actually presented to the users rather than considering only the number of video elementary streams in use.

Research aspects: It seems that visual compression and systems standards enabling immersive media applications and services are becoming mature. However, the Quality of Experience (QoE) of such applications and services is still in its infancy. The QUALINET White Paper on Definitions of Immersive Media Experience (IMEx) provides a survey of definitions of immersion and presence which leads to a definition of Immersive Media Experience (IMEx). Consequently, the next step is working towards QoE metrics in this domain that requires subjective quality assessments imposing various challenges during the current COVID-19 pandemic.

Versatile Video Coding (VVC) updates

The third round of verification testing for Versatile Video Coding (VVC) has been completed. This includes the testing of High Dynamic Range (HDR) content of 4K ultra-high-definition (UHD) resolution using the Hybrid Log-Gamma (HLG) and Perceptual Quantization (PQ) video formats. The test was conducted using state-of-the-art high-quality consumer displays, emulating an internet streaming-type scenario.

On average, VVC showed on average approximately 50% bit rate reduction compared to High Efficiency Video Coding (HEVC).

Additionally, the ISO/IEC 23008-12 Image File Format has been amended to support images coded using Versatile Video Coding (VVC) and Essential Video Coding (EVC).

Research aspects: The results of the verification tests are usually publicly available and can be used as a baseline for future improvements of the respective standards including the evaluation thereof. For example, the tradeoff compression efficiency vs. encoding runtime (time complexity) for live and video on-demand scenarios is always an interesting research aspect.

The latest MPEG-DASH Update

Finally, I’d like to provide a brief update on MPEG-DASH! At the 135th MPEG meeting, MPEG Systems issued a draft amendment to the core MPEG-DASH specification (i.e., ISO/IEC 23009-1) that provides further improvements of Preroll which is renamed to Preperiod and it will be further discussed during the Ad-hoc Group (AhG) period (please join the dash email list for further details/announcements). Additionally, this amendment includes some minor improvements for nonlinear playback. The so-called Technologies under Consideration (TuC) document comprises new proposals that did not yet reach consensus for promotion to any official standards documents (e.g., amendments to existing DASH standards or new parts). Currently, proposals for minimizing initial delay are discussed among others. Finally, libdash has been updated to support the MPEG-DASH schema according to the 5th edition.

An updated overview of DASH standards/features can be found in the Figure below.

MPEG-DASH status of July 2021.

Research aspects: The informative aspects of MPEG-DASH such as the adaptive bitrate (ABR) algorithms have been subject to research for many years. New editions of the standard mostly introduced incremental improvements but disruptive ideas rarely reached the surface. Perhaps it’s time to take a step back and re-think how streaming should work for todays and future media applications and services.

The 136th MPEG meeting will be again an online meeting in October 2021 but MPEG is aiming to meet in-person again in January 2021 (if possible). Click here for more information about MPEG meetings and their developments.

VQEG Column: VQEG Meeting Jun. 2021 (virtual/online)

Introduction

Welcome to the fifth column on the ACM SIGMM Records from the Video Quality Experts Group (VQEG).
The last VQEG plenary meeting took place online from 7 to 11 June 2021. As the previous meeting celebrated in December 2020, it was organized online (this time by Kingston University) with multiple sessions spread over five days, allowing remote participation of people from 22 different countries of America, Asia, and Europe. More than 100 participants registered to the meeting and they could attend the 40 presentations and several discussions that took place in all working groups. 
This column provides an overview of the recently completed VQEG plenary meeting, while all the information, minutes and files (including the presented slides) from the meeting are available online in the VQEG meeting website

Group picture of the VQEG Meeting 7-11 June 2021.

Several interesting presentations of state-of-the-art works can be of interest to the SIGMM community, in addition to the contributions to several working items of ITU from various VQEG groups. The progress on the new activities launched in the last VQEG plenary meeting (in relation to Live QoE assessment, SI/TI clarification, implementers guide for video quality metrics for coding applications, and the inclusion of video quality metrics as metadata in compressed streams), as well as the proposal for a new joint work on evaluation of immersive communication systems from a task-based or interactive perspective within the Immersive Media Group.

We encourage those 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)

AVHD group works on improved subjective and objective methods for video-only and audiovisual quality of commonly available systems. Currently, after the project AVHD/P.NATS2 (a joint collaboration between VQEG and ITU SG12) finished in 2020 [1], two projects are ongoing within AVHD group: QoE Metrics for Live Video Streaming Applications (Live QoE), which was launched in the last plenary meeting, and Advanced Subjective Methods (AVHD-SUB).
The main discussion during the AVHD sessions was related to the Live QoE project, which was led by Shahid Satti (Opticom) and Rohit Puri (Twitch). In addition to the presentation of the project proposal, the main decisions reached until now were exposed (e.g., use of videos of 20-30 seconds with resolution 1080p and framerates up to 60fps, use ACR as subjective test methodology, generation of test conditions, etc.), as well as open questions were brought up for discussion, especially in relation to how to acquire premium content and network traces. 
In addition to this discussion, Steve Göring (TU Ilmenau) presented and open-source platform (AVrate Voyager) for crowdsourcing/online subjective tests [2], and Shahid Satti (Opticom) presented the performance results of the Opticom models on the project AVHD/P.NATS Phase 2. Finally, Ioannis Katsavounidis (Facebook) presented the subjective testing validation of the AV1 performance from the Alliance for Open Media (AOM) to gather feedback on the test plan and possible interested testing labs from VQEG. It is also worth noting that this session was recorded to be used as raw multimedia data for the Live QoE project. 

Quality Assessment for Health applications (QAH)

The session related to the QAH group group allocated three presentations apart from the project summary provided by Lucie Lévêque (Polytech Nantes). In particular, Meriem Outtas (INSA Rennes) provided a review on objective quality assessment of medical images and videos. This is is one of the topics jointly addressed by the group, which is working on an overview paper in line with the recent review on subjective medical image quality assessment [3]. Moreover, Zohaib Amjad Khan (Université Sorbonne Paris Nord) presented a work on video quality assessment of laparoscopic videos, while Aditja Raj and Maria Martini (Kingston University) presented their work on multivariate regression-based convolutional neural network model for fundus image quality assessment.

Statistical Analysis Methods (SAM)

The SAM session consisted of three presentations followed by discussions on the topics. One of this was related to the description of subjective experiment consistency by p-value p-p plot [4], which was presented by Jakub Nawała (AGH University of Science and Technology). In addition, Zhi Li (Netflix) and Rafał Figlus (AGH University of Science and Technology) presented the progress on the contribution from SAM to the ITU-T to modify the recommendation P.913 to include the MLE model for subject behavior in subjective experiments [5] and the recently available implementation of this model in Excel. Finally, Pablo Pérez (Nokia Bell Labs) and Lucjan Janowski (AGH University of Science and Technology) presented their work on the possibility of performing subjective experiments with four subjects [6].

Computer Generated Imagery (CGI)

Nabajeet Barman (Kingston University) presented a report on the current activities of the CGI group. The main current working topics are related to gaming quality assessment methodologies and quality prediction, and codec comparison for CG content. This group is closely collaborating with the ITU-T SG12, as reflected by its support on the completion of the 3 work items: ITU-T Rec. G.1032 on influence factors on gaming quality of experience, ITU-T Rec. P.809 on subjective evaluation methods for gaming quality, and ITU-T Rec. G.1072 on opinion model for gaming applications. Furthermore, CGI is contributing to 3 new work items: ITU-T work item P.BBQCG on parametric bitstream-based quality assessment of cloud gaming services, ITU-T work item G.OMMOG on opinion models for mobile online gaming applications, and ITU-T work item P.CROWDG on subjective evaluation of gaming quality with a crowdsourcing approach. 
In addition, four presentations were scheduled during the CGI slots. The first one was delivered by Joel Jung (Tencent Media Lab) and David Lindero (Ericsson), who presented the details of the ITU-T work item P.BBQCG. Another one was related to the evaluation of MPEG-5 Part 2 (LCEVC) for gaming video streaming applications, which was presented by Nabajeet Barman (Kingston University) and Saman Zadtootaghaj (Dolby Laboratories). Also Nabajeet together with Maria Martini (Kingston University) presented a dataset, codec comparison and challenges related to user generated HDR gaming video streaming [7]. Finally, JP Tauscher (Technische Universität Braunschweig) presented his work on EEG-based detection of deep fake images. 

No Reference Metrics (NORM)

The session for NORM group included a presentation on the impact of Spatial and Temporal Information (SI and TI) on video quality and compressibility [8], delivered by Werner Robitza (AVEQ GmbH), which was followed by a fruitful discussion on the compression complexity and on the activity related to SI/TI clarification launched in the last VQEG plenary meeting. In addition, there was another presentation from Mikołaj Leszczuk (AGH University of Science and Technology) on content type indicators for technologies supporting video sequence summarization. Finally, Ioannis Katsavounidis (Facebook) led a discussion on the inclusion of video quality metrics as metadata in compressed streams, with a report on the progress on this activity that was started in the last meeting. 

Joint Effort Group (JEG) – Hybrid

The JEG-Hybrid group is currently working on the development of a generally applicable no-reference hybrid perceptual/bitstream model. In this sense, Enrico Masala and Lohic Fotio Tiotsop (Politecnico di Tornio) presented the progress on designing a neural-network approach to model single observers using existing subjectively-annotated image and video datasets [9] (the design of subjective tests tailored for the training of this approach is envisioned for future work). In addition to this activity, the group is working in collaboration with the Sky Group on the “Hodor Project”, which is based on developing a measure that could allow to automatically identify video sequences for which quality metrics are likely to deliver inaccurate Mean Opinion Score (MOS) estimation.
Apart from these joint activities Dr. Yendo Hu (Carnation Communications Inc. and Jimei University) delivered a presentation proposing to work on a benchmarking standard to bring quality, bandwidth, and latency into a common measurement domain.

Quality Assessment for Computer Vision Applications (QACoViA)

In addition to a progress report, the QACoViA group scheduled two interesting presentations on enhancing artificial intelligence resilience to image coding artifacts through expert training (by Alban Marie from INSA Rennes) and on providing datasets to rain no-reference metrics for computer vision applications (by Carolina Whitaker from NTIA/ITS). 

5G Key Performance Indicators (5GKPI)

The 5GKPI session consisted of a presentation by Pablo Pérez (Nokia Bell-Labs) of the progress achieved by the group since the last plenary meeting in the following efforts: 1) the contribution to ITU-T Study Group 12 Question 13 related through the Technical Report about QoE in 5G video services (GSTR-5GQoE), which addresses QoE requirements and factors for some use cases like Tele-operated Driving (ToD), wireless content production, mixed reality offloading and first responder networks; 2) the contribution to the 5G Automotive Association (5GAA) through a high-level contribution on general QoE requirements for remote driving, considering for the near future the execution of subjective tests for ToD video quality; and 3) the long-term plan on working on a methodology to create simple opinion models to estimate average QoE for a network and use case.

Immersive Media Group (IMG)

Several presentations were delivered during the IMG session that were divided into two blocks: one covering technologies and studies related to the evaluation of immersive communication systems from a task-based or interactive perspective, and another one covering other topics related to the assessment of QoE of immersive media. 
The first set of presentations is related to a new proposal for a joint work within IMG related to the ITU-T work item P.QXM on QoE assessment of eXtended Reality meetings. Thus, Irene Viola (CWI) presented an overview of this work item. In addition, Carlos Cortés (Universidad Politécncia de Madrid) presented his work on evaluating the impact of delay on QoE in immersive interactive environments, Irene Viola (CWI) presented a dataset of point cloud dynamic humans for immersive telecommunications, Pablo César (CWI) presented their pipeline for social virtual reality [10], and Narciso García (Universidad Politécncia de Madrid) presented their real-time free-viewpoint video system (FVVLive) [11]. After these presentations, Jesús Gutiérrez (Universidad Politécncia de Madrid) led the discussion on joint next steps with IMG, which, in addition, to identify interested parties in joining the effort to study the evaluation of immersive communication systems, also covered the further analyses to be done from the subjective tests carried out with short 360-degree videos [12] and the studies carried out to assess quality and other factors (e.g., presence) with long omnidirectional sequences. In this sense, Marta Orduna (Universidad Politécnica de Madrid) presented her subjective study to validate a methodology to assess quality, presence, empathy, attitude, and attention in Social VR [13]. Future progress on these joint activities will be discussed in the group audio-calls. 
Within the other block of presentations related to immersive media topics, Maria Martini (Kingston University), Chulhee Lee (Yonsei University), and Patrick Le Callet (Université de Nantes) presented the status of IEEE standardization on QoE for immersive experiences (IEEE P3333.1.4 – Light Field, and IEEE P3333.1.3, deep learning-based quality assessment), Kjell Brunnström (RISE) presented their work on legibility and readability in augmented reality [14], Abdallah El Ali (CWI) presented his work on investigating the relationship between momentary emotion self-reports and head and eye movements in HMD-based 360° videos [15], Elijs Dima (Mid Sweden University) exposed his study on quality of experience in augmented telepresence considering the effects of viewing positions and depth-aiding augmentation [16], Silvia Rossi (UCL) presented her work towards behavioural analysis of 6-DoF user when consuming immersive media [17], and Yana Nehme (INSA Lyon) presented a study on exploring crowdsourcing for subjective quality assessment of 3D Graphics.

Intersector Rapporteur Group on Audiovisual Quality Assessment (IRG-AVQA) and Q19 Interim Meeting

During the IRG-AVQA session, an overview on the progress and recent works within ITU-R SG6 and ITU-T SG12 was provided. In particular, Chulhee Lee (Yonsei University) in collaboration with other ITU rapporteurs presented the progress of ITU-R WP6C on recommendations for HDR content, the work items within: ITU-T SG12 Question 9 on audio-related work items, SG12 Question 13 on gaming and immersive technologies (e.g., augmented/extended reality) among others, SG12 Question 14 recommendations and work items related to the development of video quality models, and SG12 Question 19 on work items related to television and multimedia. In addition, the progress of the group “Implementers Guide for Video Quality Metrics (IGVQM)”, launched in the last plenary meeting by Ioannis Katsavounidis (Facebook) was discussed addressing specific points to push the collection of video quality models and datasets to be used to develop an implementer’s guide for objective video quality metrics for coding applications. 

Other updates

The next VQEG plenary meeting will take place online in December 2021.

In addition, VQEG is investigating the possibility to disseminate the videos from all the talks from these plenary meetings via platforms such as Youtube and Facebook.

Finally, given that some modifications are being made to the public FTP of VQEG, if the links to the presentations included in this column are not opened by the browser, the reader can download all the presentations in one compressed file.

References

[1] A. Raake, S. Borer, S. Satti, J. Gustafsson, R.R.R. Rao, S. Medagli, P. List, S. Göring, D. Lindero, W. Robitza, G. Heikkilä, S. Broom, C. Schmidmer, B. Feiten, U. Wüstenhagen, T. Wittmann, M. Obermann, and R. Bitto, “Multi-model standard for bitstream-, pixel-based and hybrid video quality assessment of UHD/4K: ITU-T P.1204”, IEEE Access, vol. 8, pp. 193020-193049, Oct. 2020.
[2] R.R.R. Rao, S. Göring, and A. Raake, “Towards High Resolution Video Quality Assessment in the Crowd”, IEEE Int. Conference on Quality of Multimedia Experience (QoMEX), Jun. 2021.
[3] L. Lévêque, M. Outtas, H. Liu, and L. Zhang, “Comparative study of the methodologies used for subjective medical image quality assessment”, Physics in Medicine & Biology, Jul. 2021 (Accepted).
[4] J. Nawala, L. Janowski, B. Cmiel, and K. Rusek, “Describing Subjective Experiment Consistency by p-Value P–P Plot”, ACM International Conference on Multimedia (ACM MM), Oct. 2020.
[5] Z. Li, C. G. Bampis, L. Krasula, L. Janowski, and I. Katsavounidis, “A Simple Model for Subject Behavior in Subjective Experiments”, arXiv:2004.02067v3, May 2021.
[6] P. Perez, L. Janowski, N. Garcia, M. Pinson, “Subjective Assessment Experiments That Recruit Few Observers With Repetitions (FOWR)”, arXiv:2104.02618, Apr. 2021.
[7] N. Barman, and M. G. Martini, “User Generated HDR Gaming Video Streaming: Dataset, Codec Comparison and Challenges”, IEEE Transactions on Circuits and Systems for Video Technology, May 2021.
[8] W. Robitza, R.R.R. Rao, S. Göring, and A. Raake, “Impact of Spatial and Temporal Information on Video Quality and Compressibility”, IEEE Int. Conference on Quality of Multimedia Experience (QoMEX), Jun. 2021.
[9] L. Fotio Tiotsop, T. Mizdos, M. Uhrina, M. Barkowsky, P. Pocta, and E. Masala, “Modeling and estimating the subjects’ diversity of opinions in video quality assessment: a neural network based approach”, Multimedia Tools and Applications, vol. 80, pp. 3469–3487, Sep. 2020.
[10] J. Jansen, S. Subramanyam, R. Bouqueau, G. Cernigliaro, M. Martos Cabré, F. Pérez, and P. Cesar, “A Pipeline for Multiparty Volumetric Video Conferencing: Transmission of Point Clouds over Low Latency DASH”, ACM Multimedia Systems Conference (MMSys), May 2020.
[11] P. Carballeira, C. Carmona, C. Díaz, D. Berjón, D. Corregidor, J. Cabrera, F. Morán, C. Doblado, S. Arnaldo, M.M. Martín, and N. García, “FVV Live: A real-time free-viewpoint video system with consumer electronics hardware”, IEEE Transactions on Multimedia, May 2021.
[12] J. Gutiérrez, P. Pérez, M. Orduna, A. Singla, C. Cortés, P. Mazumdar, I. Viola, K. Brunnström, F. Battisti, N. Cieplińska, D. Juszka, L. Janowski, M. Leszczuk, A. Adeyemi-Ejeye, Y. Hu, Z. Chen, G. Van Wallendael, P. Lambert, C. Díaz, J. Hedlund, O. Hamsis, S. Fremerey, F. Hofmeyer, A. Raake, P. César, M. Carli, N. García, “Subjective evaluation of visual quality and simulator sickness of short 360° videos: ITU-T Rec. P.919”, IEEE Transactions on Multimedia, Jul. 2021 (Early Access).
[13] M. Orduna, P. Pérez, J. Gutiérrez, and N. García, “Methodology to Assess Quality, Presence, Empathy, Attitude, and Attention in Social VR: International Experiences Use Case”, arXiv:2103.02550, 2021.
[14] J. Falk, S. Eksvärd, B. Schenkman, B. Andrén, and K. Brunnström “Legibility and readability in Augmented Reality”, IEEE Int. Conference on Quality of Multimedia Experience (QoMEX), Jun. 2021.
[15] T. Xue,  A. El Ali,  G. Ding,  and P. Cesar, “Investigating the Relationship between Momentary Emotion Self-reports and Head and Eye Movements in HMD-based 360° VR Video Watching”, Extended Abstracts of the CHI Conference on Human Factors in Computing Systems, May 2021.
[16] E. Dima, K. Brunnström, M. Sjöström, M. Andersson, J. Edlund, M. Johanson, and T. Qureshi, “Joint effects of depth-aiding augmentations and viewing positions on the quality of experience in augmented telepresence”, Quality and User Experience, vol. 5, Feb. 2020.
[17] S. Rossi, I. Viola, J. Jansen, S. Subramanyam, L. Toni, and P. Cesar, “Influence of Narrative Elements on User Behaviour in Photorealistic Social VR”, International Workshop on Immersive Mixed and Virtual Environment Systems (MMVE), Sep. 28, 2021.

JPEG Column: 91st JPEG Meeting

JPEG Committee issues a Call for Proposals on Holography coding

The 91st JPEG meeting was held online from 19 to 23 April 2021. This meeting saw several activities relating to holographic coding, notably the release of the JPEG Pleno Holography Call for Proposals, consolidated with the definition of the use cases and requirements for holographic coding and common test conditions that will assure the evaluation of the future proposals.

Reconstructed hologram from B-com database (http://plenodb.jpeg.org/).

The 91st meeting was also marked by the start of a new exploration initiative on Non-Fungible Tokens (NFTs), due to the recent interest in this technology in a large number of applications and in particular in digital art. Since NFTs rely on decentralized networks and JPEG has been analysing the implications of Blockchains and distributed ledger technologies in imaging, it is a natural next step to explore how JPEG standardization can facilitate interoperability between applications that make use of NFTs.

The following presents an overview of the major achievements carried out during the 91st JPEG meeting.

The 91st JPEG meeting had the following highlights:

  • JPEG launches call for proposals for the first standard in holographic coding,
  • JPEG NFT,
  • JPEG Fake Media,
  • JPEG AI,
  • JPEG Systems,
  • JPEG XS,
  • JPEG XL,
  • JPEG DNA,
  • JPEG Reference Software.

JPEG launches call for proposals for the first standard in holographic coding

JPEG Pleno aims to provide a standard framework for representing new imaging modalities, such as light field, point cloud, and holographic content. JPEG Pleno Holography is the first standardization effort for a versatile solution to efficiently compress holograms for a wide range of applications ranging from holographic microscopy to tomography, interferometry, and printing and display, as well as their associated hologram types. Key functionalities include support for both lossy and lossless coding, scalability, random access, and integration within the JPEG Pleno system architecture, with the goal of supporting a royalty free baseline.

The final Call for Proposals (CfP) on JPEG Pleno Holography – a milestone in the roll-out of the JPEG Pleno framework – has been issued as the main result of the 91st JPEG meeting, Online, 19-23 April 2021. The deadline for expressions of interest and registration is 1 August 2021. Submissions to the Call for Proposals are due on 1 September 2021.

A second milestone reached at this meeting was the promotion to International Standard of JPEG Pleno Part 2: Light Field Coding (ISO/IEC 21794-2). This standard provides light field coding tools originating from either microlens cameras or camera arrays. Part 1 of this standard, which was promoted to International Standard earlier, provides the overall file format syntax supporting light field, holography and point cloud modalities.

During the 91st JPEG meeting, the JPEG Committee officially began an exciting phase of JPEG Pleno Point Cloud coding standardisation with a focus on learning-based point cloud coding.

The scope of the JPEG Pleno Point Cloud activity is the creation of a learning-based coding standard for point clouds and associated attributes, offering a single-stream, compact compressed domain representation, supporting advanced flexible data access functionalities. The JPEG Pleno Point Cloud standard targets both interactive human visualization, with significant compression efficiency over state of the art point cloud coding solutions commonly used at equivalent subjective quality, and also enables effective performance for 3D processing and computer vision tasks. The JPEG Committee expects the standard to support a royalty-free baseline.

The standard is envisioned to provide a number of unique benefits, including an efficient single point cloud representation for both humans and machines. The intent is to provide humans with the ability to visualise and interact with the point cloud geometry and attributes while providing machines the ability to perform 3D processing and computer vision tasks in the compressed domain, enabling lower complexity and higher accuracy through the use of compressed domain features extracted from the original instead of the lossily decoded point cloud.

JPEG NFT

Non-Fungible Tokens have been the focus of much attention in recent months. Several digitals assets that NFTs point to are either in existing JPEG formats or can be represented in current and emerging formats under development by the JPEG Committee. Furthermore, several trust and security issues have been raised regarding NFTs and the digital assets they rely on. Here again, JPEG Committee has a significant track record in security and trust in imaging applications. Building on this background, the JPEG Committee has launched a new exploration initiative around NFTs to better understand the needs in terms of imaging requirements and how existing as well as potential JPEG standards can help bring security and trust to NFTs in a wide range of applications and notably those that rely on contents that are represented in JPEG formats in still and animated pictures and 3D contents. The first steps in this initiative involve outreach to stakeholders in NFTs and its application and organization of a workshop to discuss challenges and current solutions in NFTs, notably in the context of applications relevant to the scope of the JPEG Standardization Committee. JPEG Committee invites interested parties to subscribe to the mailing list of the JPEG NFT exploration via http://listregistration.jpeg.org.

JPEG Fake Media

The JPEG Fake Media exploration activity continues its work to assess standardization needs to facilitate secure and reliable annotation of media asset creation and modifications in good faith usage scenarios as well as in those with malicious intent. At the 91st meeting, the JPEG Committee released an updated version of the “JPEG Fake Media Context, Use Cases and Requirements” document. This new version includes several refinements including an improved and coherent set of definitions covering key terminology. The requirements have been extended and reorganized into three main identified categories: media creation and modification descriptions, metadata embedding framework and authenticity verification framework. The presentations and video recordings of the 2nd Workshop on JPEG Fake Media are now available on the JPEG website. JPEG invites interested parties to regularly visit https://jpeg.org/jpegfakemedia for the latest information and subscribe to the mailing list via http://listregistration.jpeg.org.

JPEG AI

At the 91st meeting, the results of the JPEG AI exploration experiments for the image processing and computer vision tasks defined at the previous 90th meeting were presented and discussed. Based on the analysis of the results, the exploration experiments description was improved. This activity will allow the definition of a performance assessment framework to use in the learning-based image codecs latent representation in several visual analysis tasks, such as compressed domain image classification and compressed domain material and texture recognition. Moreover, the impact of such experiments on the current version of the Common Test Conditions (CTC) was discussed. 

Moreover, the draft of the Call for Proposals was analysed, notably regarding the training dataset and training procedures as well as the submission requirements. The timeline of the JPEG AI work item was discussed and it was agreed that the final Call for Proposals (CfP) will be issued as an outcome of the 93rd JPEG Meeting. The deadline for expression of interest and registration is 5 November 2021. Further, the submission of bitstreams and decoded images for the test dataset are due on 30 January 2022.

JPEG Systems

During the 91st meeting, the Draft International Standard (DIS) text of JLINK (ISO/IEC 19566-7) and Committee Draft (CD) text of JPEG Snack (ISO/IEC 19566-8) were completed and will be submitted for ballot. Amendments for JUMBF (ISO/IEC 19566-5 AMD1) and JPEG 360 (ISO/IEC 19566-6 AMD1) received a final review and are being released for publication. In addition, new extensions to JUMBF (ISO/IEC 19566-5) are under consideration to support rapidly emerging use cases related to content authenticity and integrity; updated use cases and requirements are being drafted. Finally, discussions have started to create awareness on how to interact with JUMBF boxes and the information they contain, without breaking integrity or interoperability. Interested parties are invited to subscribe to the mailing list of the JPEG Systems AHG in order to contribute to the above activities via http://listregistration.jpeg.org.

JPEG XS

The second editions of JPEG XS Part 1 (Core coding system) and Part 3 (Transport and container formats) were prepared for Final Draft International Standard (FDIS) balloting, with the intention of having both standards published by October 2021. The second editions integrate new coding and signalling capabilities to support RAW Bayer colour filter array (CFA) images, 4:2:0 sampled images and mathematically lossless coding of up to 12-bits per component. The associated profiles and buffer models are handled in Part 2, which is currently under DIS ballot. The focus now has shifted to work on the second editions of Part 4 (Conformance testing) and Part 5 (Reference software). Finally, the JPEG Committee defined a study to investigate future improvements to high dynamic range (HDR) and mathematically lossless compression capabilities, while still honouring the low-complexity and low-latency requirements. In particular, for RAW Bayer CFA content, the JPEG Committee will work on extensions of JPEG XS supporting lossless compression of CFA patterns at sample bit depths above 12 bits.

JPEG XL

The JPEG Committee has finalized JPEG XL Part 2 (File format), which is now at the FDIS stage. A Main profile has been specified in draft Amendment 1 to Part 1, which entered the draft amendment (DAM) stage of the approval process at the current meeting. The draft Main profile has two levels: Level 5 for end-user image delivery and Level 10 for generic use cases, including image authoring workflows. Now that the criteria for conformance have been determined, the JPEG Committee has defined new core experiments to define a set of test codestreams that provides full coverage of the coding tools. Part 4 (Reference software) is now at the DIS stage. With the first edition FDIS texts of both Part 1 and Part 2 now complete, JPEG XL is ready for wide adoption.

JPEG DNA

The JPEG Committee has continued its exploration of coding of images in quaternary representation, particularly suitable for DNA storage. After a successful third workshop presentation by stakeholders, two new use cases were identified along with a large number of new requirements, and a new version of the JPEG DNA overview document was issued and is now made publicly available. It was decided to continue this exploration by organizing the fourth workshop and conducting further outreach to stakeholders, as well as continuing with improving the JPEG DNA overview document.

Interested parties are invited to refer to the following URL and to consider joining the effort by registering to the mailing list of JPEG DNA here: https://jpeg.org/jpegdna/index.html.

JPEG Reference Software

The JPEG Committee is pleased to announce that its standard on the JPEG reference software, 2nd edition, reached the state of International Standard and will be publicly available from both ITU and ISO/IEC.

This standard, to appear as ITU-T T.873 | ISO/IEC 10918-7 (2nd Edition) provides reference implementations to the first JPEG standard, used daily throughout the world. The software included in this document guides vendors on how JPEG (ISO/IEC 10918-1) can be implemented and may serve as a baseline and starting point for JPEG
encoders or decoders.

This second edition updates the two reference implementations to their latest versions, fixing minor defects in the software.

Final Quote

“JPEG standards continue to be a motor of innovation and an enabler of new applications in imaging as witnessed by the release of the first standard for coding of holographic content.” said Prof. Touradj Ebrahimi, the Convenor of the JPEG Committee.

Future JPEG meetings are planned as follows:

  • No. 92, will be held online from 7 to 13 July 2021.
  • No 93, is planned to be held in Berlin, Germany during 16-22 October 2021.

MPEG Column: 134th MPEG Meeting (virtual/online)

The original blog post can be found at the Bitmovin Techblog and has been modified/updated here to focus on and highlight research aspects.

The 134th MPEG meeting was once again held as an online meeting, and the official press release can be found here and comprises the following items:

  • First International Standard on Neural Network Compression for Multimedia Applications
  • Completion of the carriage of VVC and EVC
  • Completion of the carriage of V3C in ISOBMFF
  • Call for Proposals: (a) new Advanced Genomics Features and Technologies, (b) MPEG-I Immersive Audio, and (c) coded Representation of Haptics
  • MPEG evaluated Responses on Incremental Compression of Neural Networks
  • Progression of MPEG 3D Audio Standards
  • The first milestone of development of Open Font Format (2nd amendment)
  • Verification tests: (a) low Complexity Enhancement Video Coding (LCEVC) Verification Test and (b) more application cases of Versatile Video Coding (VVC)
  • Standardization work on Version 2 of VVC and VSEI started

In this column, the focus is on streaming-related aspects including a brief update about MPEG-DASH.

First International Standard on Neural Network Compression for Multimedia Applications

Artificial neural networks have been adopted for a broad range of tasks in multimedia analysis and processing, such as visual and acoustic classification, extraction of multimedia descriptors, or image and video coding. The trained neural networks for these applications contain many parameters (i.e., weights), resulting in a considerable size. Thus, transferring them to several clients (e.g., mobile phones, smart cameras) benefits from a compressed representation of neural networks.

At the 134th MPEG meeting, MPEG Video ratified the first international standards on Neural Network Compression for Multimedia Applications (ISO/IEC 15938-17), designed as a toolbox of compression technologies. The specification contains different methods for

  • parameter reduction (e.g., pruning, sparsification, matrix decomposition),
  • parameter transformation (e.g., quantization), and
  • entropy coding 

methods that can be assembled to encoding pipelines combining one or more (in the case of reduction) methods from each group.

The results show that trained neural networks for many common multimedia problems such as image or audio classification or image compression can be compressed by a factor of 10-20 with no performance loss and even by more than 30 with performance trade-off. The specification is not limited to a particular neural network architecture and is independent of the neural network exchange format choice. The interoperability with common neural network exchange formats is described in the annexes of the standard.

As neural networks are becoming increasingly important, the communication thereof over heterogeneous networks to a plethora of devices raises various challenges including efficient compression that is inevitable and addressed in this standard. ISO/IEC 15938 is commonly referred to as MPEG-7 (or the “multimedia content description interface”) and this standard becomes now part 15 of MPEG-7.

Research aspects: Like for all compression-related standards, research aspects are related to compression efficiency (lossy/lossless), computational complexity (runtime, memory), and quality-related aspects. Furthermore, the compression of neural networks for multimedia applications probably enables new types of applications and services to be deployed in the (near) future. Finally, simultaneous delivery and consumption (i.e., streaming) of neural networks including incremental updates thereof will become a requirement for networked media applications and services.

Carriage of Media Assets

At the 134th MPEG meeting, MPEG Systems completed the carriage of various media assets in MPEG-2 Systems (Transport Stream) and the ISO Base Media File Format (ISOBMFF), respectively.

In particular, the standards for the carriage of Versatile Video Coding (VVC) and Essential Video Coding (EVC) over both MPEG-2 Transport Stream (M2TS) and ISO Base Media File Format (ISOBMFF) reached their final stages of standardization, respectively:

  • For M2TS, the standard defines constraints to elementary streams of VVC and EVC to carry them in the packetized elementary stream (PES) packets. Additionally, buffer management mechanisms and transport system target decoder (T-STD) model extension are also defined.
  • For ISOBMFF, the carriage of codec initialization information for VVC and EVC is defined in the standard. Additionally, it also defines samples and sub-samples reflecting the high-level bitstream structure and independently decodable units of both video codecs. For VVC, signaling and extraction of a certain operating point are also supported.

Finally, MPEG Systems completed the standard for the carriage of Visual Volumetric Video-based Coding (V3C) data using ISOBMFF. Therefore, it supports media comprising multiple independent component bitstreams and considers that only some portions of immersive media assets need to be rendered according to the users’ position and viewport. Thus, the metadata indicating the relationship between the region in the 3D spatial data to be rendered and its location in the bitstream is defined. In addition, the delivery of the ISOBMFF file containing a V3C content over DASH and MMT is also specified in this standard.

Research aspects: Carriage of VVC, EVC, and V3C using M2TS or ISOBMFF provides an essential building block within the so-called multimedia systems layer resulting in a plethora of research challenges as it typically offers an interoperable interface to the actual media assets. Thus, these standards enable efficient and flexible provisioning or/and use of these media assets that are deliberately not defined in these standards and subject to competition.

Call for Proposals and Verification Tests

At the 134th MPEG meeting, MPEG issued three Call for Proposals (CfPs) that are briefly highlighted in the following:

  • Coded Representation of Haptics: Haptics provide an additional layer of entertainment and sensory immersion beyond audio and visual media. This CfP aims to specify a coded representation of haptics data, e.g., to be carried using ISO Base Media File Format (ISOBMFF) files in the context of MPEG-DASH or other MPEG-I standards.
  • MPEG-I Immersive Audio: Immersive Audio will complement other parts of MPEG-I (i.e., Part 3, “Immersive Video” and Part 2, “Systems Support”) in order to provide a suite of standards that will support a Virtual Reality (VR) or an Augmented Reality (AR) presentation in which the user can navigate and interact with the environment using 6 degrees of freedom (6 DoF), that being spatial navigation (x, y, z) and user head orientation (yaw, pitch, roll).
  • New Advanced Genomics Features and Technologies: This CfP aims to collect submissions of new technologies that can (i) provide improvements to the current compression, transport, and indexing capabilities of the ISO/IEC 23092 standards suite, particularly applied to data consisting of very long reads generated by 3rd generation sequencing devices, (ii) provide the support for representation and usage of graph genome references, (iii) include coding modes relying on machine learning processes, satisfying data access modalities required by machine learning and providing higher compression, and (iv) support of interfaces with existing standards for the interchange of clinical data.

Detailed information, including instructions on how to respond to the call for proposals, the requirements that must be considered, the test data to be used, and the submission and evaluation procedures for proponents are available at www.mpeg.org.

Call for proposals typically mark the beginning of the formal standardization work whereas verification tests are conducted once a standard has been completed. At the 134th MPEG meeting and despite the difficulties caused by the pandemic situation, MPEG completed verification tests for Versatile Video Coding (VVC) and Low Complexity Enhancement Video Coding (LCEVC).

For LCEVC, verification tests measured the benefits of enhancing four existing codecs of different generations (i.e., AVC, HEVC, EVC, VVC) using tools as defined in LCEVC within two sets of tests:

  • The first set of tests compared LCEVC-enhanced encoding with full-resolution single-layer anchors. The average bit rate savings produced by LCEVC when enhancing AVC were determined to be approximately 46% for UHD and 28% for HD. When enhancing HEVC approximately 31% for UHD and 24% for HD. Test results tend to indicate an overall benefit also when using LCEVC to enhance EVC and VVC.
  • The second set of tests confirmed that LCEVC provided a more efficient means of resolution enhancement of half-resolution anchors than unguided up-sampling. Comparing LCEVC full-resolution encoding with the up-sampled half-resolution anchors, the average bit-rate savings when using LCEVC with AVC, HEVC, EVC and VVC were calculated to be approximately 28%, 34%, 38%, and 32% for UHD and 27%, 26%, 21%, and 21% for HD, respectively.

For VVC, it was already the second round of verification testing including the following aspects:

  • 360-degree video for equirectangular and cubemap formats, where VVC shows on average more than 50% bit rate reduction compared to the previous major generation of MPEG video coding standard known as High Efficiency Video Coding (HEVC), developed in 2013.
  • Low-delay applications such as compression of conversational (teleconferencing) and gaming content, where the compression benefit is about 40% on average,
  • HD video streaming, with an average bit rate reduction of close to 50%.

A previous set of tests for 4K UHD content completed in October 2020 had shown similar gains. These verification tests used formal subjective visual quality assessment testing with “naïve” human viewers. The tests were performed under a strict hygienic regime in two test laboratories to ensure safe conditions for the viewers and test managers.

Research aspects: CfPs offer a unique possibility for researchers to propose research results for adoption into future standards. Verification tests provide objective or/and subjective evaluations of standardized tools which typically conclude the life cycle of a standard. The results of the verification tests are usually publicly available and can be used as a baseline for future improvements of the respective standards including the evaluation thereof.

DASH Update!

Finally, I’d like to provide a brief update on MPEG-DASH! At the 134th MPEG meeting, MPEG Systems recommended the approval of ISO/IEC FDIS 23009-1 5th edition. That is, the MPEG-DASH core specification will be available as 5th edition sometime this year. Additionally, MPEG requests that this specification becomes freely available which also marks an important milestone in the development of the MPEG-DASH standard. Most importantly, the 5th edition of this standard incorporates CMAF support as well as other enhancements defined in the amendment of the previous edition. Additionally, the MPEG-DASH subgroup of MPEG Systems is already working on the first amendment to its 5th edition entitled preroll, nonlinear playback, and other extensions. It is expected that the 5th edition will also impact related specifications within MPEG but also in other Standards Developing Organizations (SDOs) such as DASH-IF, i.e., defining interoperability points (IOPs) for various codecs and others, or CTA WAVE (Web Application Video Ecosystem), i.e., defining device playback capabilities such as the Common Media Client Data (CMCD). Both DASH-IF and CTA WAVE provide means for (conformance) test infrastructure for DASH and CMAF.

An updated overview of DASH standards/features can be found in the Figure below.

MPEG-DASH status as of April 2021.

Research aspects: MPEG-DASH has been ratified almost ten years ago which resulted in a plethora of research articles, mostly related to adaptive bitrate (ABR) algorithms and their impact on the streaming performance including the Quality of Experience (QoE). An overview of bitrate adaptation schemes is provided here including a list of open challenges and issues.

The 135th MPEG meeting will be again an online meeting in July 2021. Click here for more information about MPEG meetings and their developments.

Encouraging more Diverse Scientific Collaborations with the ConfFlow application

Introduction

ConfFlow is an application to encourage people with similar or complementary research interests to find each other at conferences. How scientific collaborations are initiated, how people meet and how an intention is developed to work together is an open question. The aim of this follow-up initiative to ConfLab: Meet the Chairs! held at ACM MM 2019 (conflab.ewi.tudelft.nl) is to help people in the multimedia community to connect with potential collaborators.

As a community, Multimedia is so diverse that it is easy for community members to miss out on very useful expertise and potentially fruitful collaborations. There is a lot of latent knowledge and potential synergies that could exist if we were to offer conference attendees an alternative perspective on their similarities to other attendees. As researchers, we typically find connections through talking to people at the conference either through scientific presentations, personal introductions, or by chance.

The aim of ConfFlow is to allow attendees to browse their similarity to other attendees by harvesting publicly available information about them related to their research interests. Depending on the richness of experience that users are looking for, ConfFlow aims to offer an alternative way for researchers to make new research connections with a similar space. At the basic level, we define the similarity of attendees with an approach similar to paper-reviewer assignment tools, such as the Toronto Paper Matching System (TPMS). Usually, TPMS is used to match reviewers to papers. In an analogous way, ConfFlow creates a visualised similarity space using the publications of the conference attendees. This will allow attendees to interactively explore and find new connections with researchers with complementary research interests (or similar ones).  More details about ConfFlow can be found in the associated demo paper [1]. An example snapshot of the application is shown in Figure 1 below.

ConfFlow was funded by the SIGMM special initiatives fund which supports initiatives related to boosting excellence and strength of SIGMM, addressing opportunities for growth in the community and SIGMM related activities, as well as nurturing new talent. The aim of ConfFlow is to target building on excellence, strengths, and community. 

Figure 1: Visualisation of ConfFlow

This report records our experience and practical issues related to running ConfFlow at ACM Multimedia last year.

Method

Privacy and Ethical Practices

The aim of ConfFlow was to adhere to the highest levels of ethical practice. One of the debates online relates to what is considered private data. One could consider that deriving novel information from publicly available data can still be considered an invasion of privacy [2]. So ConfFlow was proposed and designed to be opt-in only. This means that unlike the visualisation seen in Figure 1, all the identities for anyone visiting the ConfFlow application appeared as just an icon unless the person had activated their account and gave permission for others to see it. While this might seem quite strict, there can be unforeseen privacy related questions when social information is extracted from publicly available information as those who do not choose to opt-in can still become exposed. 

Due to this opt-in strict procedure, we needed to find an active way to engage conference attendees by advertising the application through the conference and also getting access to the conference attendee list so we could target and encourage those people to activate their accounts. This required close coordination with the General Chairs of ACM Multimedia 2020.

Application Realization

ConfFlow was rolled out at ACM Multimedia 2020 for conference attendees. Shortly after the building of this application was approved, the Corona Virus pandemic hit and ACM Multimedia became a virtual conference. Since the embedding space of ConfFlow needs to be built apriori, we needed to have access to the conference attendee list. The workload for the conference organisers increased significantly as a result of the pandemic so we did not manage to get the logistical support to optimise the impact of the application. Since we could not get this, we defaulted to visualising the much larger accepted author list. Each identity in ConfFlow needs to be manually verified which also takes considerable effort.

However, there remained the issue that the application was opt-in. For those who tested the application, they were disappointed because many people were not visible. Many of the authors in any case did not attend the conference, which exacerbated the sparsity issue. Advertising ConfFlow and encouraging participants to activate their account was extremely hard due to the virtual format of the conference and because it was hard to reach the actual conference attendees. 

The demo paper for the application was presented at ACM Multimedia 2020 and received positively.

Discussion and Recommendations

The instantiation of the app was well-received by community members and the SIGMM board. There were some teething problems that we aim to resolve in a follow up to the 2021 edition where we will revise the opt-in policy to something that can allow for a better user experience whilst being careful with individual privacy. We also want to make the possibility for users to connect with people they see in the embedding space directly in the app so that the use of ConfFlow as a social connector tool becomes more explicit. We also plan to focus on different ways to advertise and communicate the application for a wider userbase. Finally, due to the considerable effort required to verify the identities of all individuals in the visualisations, we would like to build a more efficient procedure to make visualisations in future years less manually intensive. To this end, the SIGMM board has funded a second edition of ConfFlow in order for these improvements to be made so we can realise the full potential of the idea while also minimising too much additional logistical support from conference general chairs. We look forward to seeing its impact on future research collaborations.

Acknowledgements

ConfFlow was supported in part by the SIGMM New Initiatives Fund and the Dutch NWO funded MINGLE project number 639.022.606. We thank users who gave feedback on the application during prototyping and implementation and the General Chairs of ACM Multimedia 2020 for their support.

References

[1] Ekin Gedik and Hayley Hung. 2020. ConfFlow: A Tool to Encourage New Diverse Collaborations. In Proceedings of the 28th ACM International Conference on Multimedia (MM ’20). Association for Computing Machinery, New York, NY, USA, 4562–4564. DOI:https://doi.org/10.1145/3394171.3414459.
[2] Townsend, L., & Wallace, C, 2016. Social Media Research: A Guide to Ethics.