MPEG news: a report from the 121st meeting, Gwangju, Korea

The original blog post can be found at the Bitmovin Techblog and has been updated here to focus on and highlight research aspects. Additionally, this version of the blog post will be also posted at ACM SIGMM Records.

MPEG News Archive

The MPEG press release comprises the following topics:

• Compact Descriptors for Video Analysis (CDVA) reaches Committee Draft level
• MPEG-G standards reach Committee Draft for metadata and APIs
• MPEG issues Calls for Visual Test Material for Immersive Applications
• Internet of Media Things (IoMT) reaches Committee Draft level
• MPEG finalizes its Media Orchestration (MORE) standard

At the end I will also briefly summarize what else happened with respect to DASH, CMAF, OMAF as well as discuss future aspects of MPEG.

Compact Descriptors for Video Analysis (CDVA) reaches Committee Draft level

The Committee Draft (CD) for CDVA has been approved at the 121st MPEG meeting, which is the first formal step of the ISO/IEC approval process for a new standard. This will become a new part of MPEG-7 to support video search and retrieval applications (ISO/IEC 15938-15).

Managing and organizing the quickly increasing volume of video content is a challenge for many industry sectors, such as media and entertainment or surveillance. One example task is scalable instance search, i.e., finding content containing a specific object instance or location in a very large video database. This requires video descriptors which can be efficiently extracted, stored, and matched. Standardization enables extracting interoperable descriptors on different devices and using software from different providers, so that only the compact descriptors instead of the much larger source videos can be exchanged for matching or querying. The CDVA standard specifies descriptors that fulfil these needs and includes (i) the components of the CDVA descriptor, (ii) its bitstream representation and (iii) the extraction process. The final standard is expected to be finished in early 2019.

CDVA introduces a new descriptor based on features which are output from a Deep Neural Network (DNN). CDVA is robust against viewpoint changes and moderate transformations of the video (e.g., re-encoding, overlays), it supports partial matching and temporal localization of the matching content. The CDVA descriptor has a typical size of 2–4 KBytes per second of video. For typical test cases, it has been demonstrated to reach a correct matching rate of 88% (at 1% false matching rate).

Research aspects: There are probably endless research aspects in the visual descriptor space ranging from validation of the achieved to results so far to further improving informative aspects with the goal to increase correct matching rate (and consequently decreasing the false matching rating). In general, however, the question is whether there's a need for descriptors in the era of bandwidth-storage-computing over-provisioning and the raising usage of artificial intelligence techniques such as machine learning and deep learning.

MPEG-G standards reach Committee Draft for metadata and APIs

In my previous report I introduced the MPEG-G standard for compression and transport technologies of genomic data. At the 121st MPEG meeting, metadata and APIs reached CD level. The former - metadata - provides relevant information associated to genomic data and the latter - APIs - allow for building interoperable applications capable of manipulating MPEG-G files. Additional standardization plans for MPEG-G include the CDs for reference software (ISO/IEC 23092-4) and conformance (ISO/IEC 23092-4), which are planned to be issued at the next 122nd MPEG meeting with the objective of producing Draft International Standards (DIS) at the end of 2018.

Research aspects: Metadata typically enables certain functionality which can be tested and evaluated against requirements. APIs allow to build applications and services on top of the underlying functions, which could be a driver for research projects to make use of such APIs.

MPEG issues Calls for Visual Test Material for Immersive Applications

I have reported about the Omnidirectional Media Format (OMAF) in my previous report. At the 121st MPEG meeting, MPEG was working on extending OMAF functionalities to allow the modification of viewing positions, e.g., in case of head movements when using a head-mounted display, or for use with other forms of interactive navigation. Unlike OMAF which only provides 3 degrees of freedom (3DoF) for the user to view the content from a perspective looking outwards from the original camera position, the anticipated extension will also support motion parallax within some limited range which is referred to as 3DoF+. In the future with further enhanced technologies, a full 6 degrees of freedom (6DoF) will be achieved with changes of viewing position over a much larger range. To develop technology in these domains, MPEG has issued two Calls for Test Material in the areas of 3DoF+ and 6DoF, asking owners of image and video material to provide such content for use in developing and testing candidate technologies for standardization. Details about these calls can be found at https://mpeg.chiariglione.org/.

Research aspects: The good thing about test material is that it allows for reproducibility, which is an important aspect within the research community. Thus, it is more than appreciated that MPEG issues such a call and let's hope that this material will become publicly available. Typically this kind of visual test material targets coding but it would be also interesting to have such test content for storage and delivery.

Internet of Media Things (IoMT) reaches Committee Draft level

The goal of IoMT is is to facilitate the large-scale deployment of distributed media systems with interoperable audio/visual data and metadata exchange. This standard specifies APIs providing media things (i.e., cameras/displays and microphones/loudspeakers, possibly capable of significant processing power) with the capability of being discovered, setting-up ad-hoc communication protocols, exposing usage conditions, and providing media and metadata as well as services processing them. IoMT APIs encompass a large variety of devices, not just connected cameras and displays but also sophisticated devices such as smart glasses, image/speech analyzers and gesture recognizers. IoMT enables the expression of the economic value of resources (media and metadata) and of associated processing in terms of digital tokens leveraged by the use of blockchain technologies.

Research aspects: The main focus of IoMT is APIs which provides easy and flexible access to the underlying device' functionality and, thus, are an important factor to enable research within this interesting domain. For example, using these APIs to enable communicates among these various media things could bring up new forms of interaction with these technologies.

MPEG finalizes its Media Orchestration (MORE) standard

MPEG "Media Orchestration" (MORE) standard reached Final Draft International Standard (FDIS), the final stage of development before being published by ISO/IEC. The scope of the Media Orchestration standard is as follows:

• It supports the automated combination of multiple media sources (i.e., cameras, microphones) into a coherent multimedia experience.
• It supports rendering multimedia experiences on multiple devices simultaneously, again giving a consistent and coherent experience.
• It contains tools for orchestration in time (synchronization) and space.

MPEG expects that the Media Orchestration standard to be especially useful in immersive media settings. This applies notably in social virtual reality (VR) applications, where people share a VR experience and are able to communicate about it. Media Orchestration is expected to allow synchronizing the media experience for all users, and to give them a spatially consistent experience as it is important for a social VR user to be able to understand when other users are looking at them.

Research aspects: This standard enables the social multimedia experience proposed in literature. Interestingly, the W3C is working on something similar referred to as timing object and it would be interesting to see whether these approaches have some commonalities.

What else happened at the MPEG meeting?

DASH is fully in maintenance mode and we are still waiting for the 3rd edition which is supposed to be a consolidation of existing corrigenda and amendments. Currently only minor extensions are proposed and conformance/reference software is being updated. Similar things can be said for CMAF where we have one amendment and one corrigendum under development. Additionally, MPEG is working on CMAF conformance. OMAF has reached FDIS at the last meeting and MPEG is working on reference software and conformance also. It is expected that in the future we will see additional standards and/or technical reports defining/describing how to use CMAF and OMAF in DASH.

Regarding the future video codec, the call for proposals is out since the last meeting as announced in my previous report and responses are due for the next meeting. Thus, it is expected that the 122nd MPEG meeting will be the place to be in terms of MPEG’s future video codec. Speaking about the future, shortly after the 121st MPEG, Leonardo Chiariglione published a blog post entitled “a crisis, the causes and a solution”, which is related to HEVC licensing, Alliance for Open Media (AOM), and possible future options. The blog post certainly caused some reactions within the video community at large and I think this was also intended. Let’s hope it will galvanice the video industry -- not to push the button -- but to start addressing and resolving the issues. As pointed out in one of my other blog posts about what to care about in 2018, the upcoming MPEG meeting in April 2018 is certainly a place to be. Additionally, it highlights some conferences related to various aspects also discussed in MPEG which I'd like to republish here:

• QoMEX -- Int'l Conf. on Quality of Multimedia Experience -- will be hosted in Sardinia, Italy from May 29-31, which is THE conference to be for QoE of multimedia applications and services. Submission deadline is January 15/22, 2018.
• MMSys -- Multimedia Systems Conf. -- and specifically Packet Video, which will be on June 12 in Amsterdam, The Netherlands. Packet Video is THE adaptive streaming scientific event 2018. Submission deadline is March 1, 2018.
• Additionally, you might be interested in ICME (July 23-27, 2018, San Diego, USA), ICIP (October 7-10, 2018, Athens, Greece; specifically in the context of video coding), and PCS (June 24-27, 2018, San Francisco, CA, USA; also in the context of video coding).
• The DASH-IF academic track hosts special events at MMSys (Excellence in DASH Award) and ICME (DASH Grand Challenge).
• MIPR -- 1st Int'l Conf. on Multimedia Information Processing and Retrieval -- will be in Miami, Florida, USA from April 10-12, 2018. It has a broad range of topics including networking for multimedia systems as well as systems and infrastructures.

MPEG news: a report from the 117th meeting, Geneva, Switzerland

The original blog post can be found at the Bitmovin Techblog and has been updated here to focus on and highlight research aspects. Additionally, this version of the blog post will be also posted at ACM SIGMM Records.

MPEG News Archive

The 117th MPEG meeting was held in Geneva, Switzerland and its press release highlights the following aspects:

• MPEG issues Committee Draft of the Omnidirectional Media Application Format (OMAF)
• MPEG-H 3D Audio Verification Test Report
• MPEG Workshop on 5-Year Roadmap Successfully Held in Geneva
• Call for Proposals (CfP) for Point Cloud Compression (PCC)
• Preliminary Call for Evidence on video compression with capability beyond HEVC
• MPEG issues Committee Draft of the Media Orchestration (MORE) Standard
• Technical Report on HDR/WCG Video Coding

In this blog post, I'd like to focus on the topics related to multimedia communication. Thus, let's start with OMAF.

Omnidirectional Media Application Format (OMAF)

Real-time entertainment services deployed over the open, unmanaged Internet – streaming audio and video – account now for more than 70% of the evening traffic in North American fixed access networks and it is assumed that this figure will reach 80 percent by 2020. More and more such bandwidth hungry applications and services are pushing onto the market including immersive media services such as virtual reality and, specifically 360-degree videos. However, the lack of appropriate standards and, consequently, reduced interoperability is becoming an issue. Thus, MPEG has started a project referred to as Omnidirectional Media Application Format (OMAF). The first milestone of this standard has been reached and the committee draft (CD) has been approved at the 117th MPEG meeting. Such application formats "are essentially superformats that combine selected technology components from MPEG (and other) standards to provide greater application interoperability, which helps satisfy users' growing need for better-integrated multimedia solutions" [MPEG-A]." In the context of OMAF, the following aspects are defined:

• Equirectangular projection format (note: others might be added in the future)
• Metadata for interoperable rendering of 360-degree monoscopic and stereoscopic audio-visual data
• Storage format: ISO base media file format (ISOBMFF)
• Codecs: High Efficiency Video Coding (HEVC) and MPEG-H 3D audio

OMAF is the first specification which is defined as part of a bigger project currently referred to as ISO/IEC 23090 -- Immersive Media (Coded Representation of Immersive Media). It currently has the acronym MPEG-I and we have previously used MPEG-VR which is now replaced by MPEG-I (that still might chance in the future). It is expected that the standard will become Final Draft International Standard (FDIS) by Q4 of 2017. Interestingly, it does not include AVC and AAC, probably the most obvious candidates for video and audio codecs which have been massively deployed in the last decade and probably still will be a major dominator (and also denominator) in upcoming years. On the other hand, the equirectangular projection format is currently the only one defined as it is broadly used already in off-the-shelf hardware/software solutions for the creation of omnidirectional/360-degree videos. Finally, the metadata formats enabling the rendering of 360-degree monoscopic and stereoscopic video is highly appreciated. A solution for MPEG-DASH based on AVC/AAC utilizing equirectangular projection format for both monoscopic and stereoscopic video is shown as part of Bitmovin's solution for VR and 360-degree video.

Research aspects related to OMAF can be summarized as follows:

• HEVC supports tiles which allow for efficient streaming of omnidirectional video but HEVC is not as widely deployed as AVC. Thus, it would be interesting how to mimic such a tile-based streaming approach utilizing AVC.
• The question how to efficiently encode and package HEVC tile-based video is an open issue and call for a tradeoff between tile flexibility and coding efficiency.
• When combined with MPEG-DASH (or similar), there's a need to update the adaptation logic as the with tiles yet another dimension is added that needs to be considered in order to provide a good Quality of Experience (QoE).
• QoE is a big issue here and not well covered in the literature. Various aspects are worth to be investigated including a comprehensive dataset to enable reproducibility of research results in this domain. Finally, as omnidirectional video allows for interactivity, also the user experience is becoming an issue which needs to be covered within the research community.

A second topic I'd like to highlight in this blog post is related to the preliminary call for evidence on video compression with capability beyond HEVC.

Preliminary Call for Evidence on video compression with capability beyond HEVC

A call for evidence is issued to see whether sufficient technological potential exists to start a more rigid phase of standardization. Currently, MPEG together with VCEG have developed a Joint Exploration Model (JEM) algorithm that is already known to provide bit rate reductions in the range of 20-30% for relevant test cases, as well as subjective quality benefits. The goal of this new standard -- with a preliminary target date for completion around late 2020 -- is to develop technology providing better compression capability than the existing standard, not only for conventional video material but also for other domains such as HDR/WCG or VR/360-degrees video. An important aspect in this area is certainly over-the-top video delivery (like with MPEG-DASH) which includes features such as scalability and Quality of Experience (QoE). Scalable video coding has been added to video coding standards since MPEG-2 but never reached wide-spread adoption. That might change in case it becomes a prime-time feature of a new video codec as scalable video coding clearly shows benefits when doing dynamic adaptive streaming over HTTP. QoE did find its way already into video coding, at least when it comes to evaluating the results where subjective tests are now an integral part of every new video codec developed by MPEG (in addition to usual PSNR measurements). Therefore, the most interesting research topics from a multimedia communication point of view would be to optimize the DASH-like delivery of such new codecs with respect to scalability and QoE. Note that if you don't like scalable video coding, feel free to propose something else as long as it reduces storage and networking costs significantly.

MPEG Workshop “Global Media Technology Standards for an Immersive Age”

On January 18, 2017 MPEG successfully held a public workshop on “Global Media Technology Standards for an Immersive Age” hosting a series of keynotes from Bitmovin, DVB, Orange, Sky Italia, and Technicolor. Stefan Lederer, CEO of Bitmovin discussed today's and future challenges with new forms of content like 360°, AR and VR. All slides are available here and MPEG took their feedback into consideration in an update of its 5-year standardization roadmap. David Wood (EBU) reported on the DVB VR study mission and Ralf Schaefer (Technicolor) presented a snapshot on VR services. Gilles Teniou (Orange) discussed video formats for VR pointing out a new opportunity to increase the content value but also raising a question what is missing today. Finally, Massimo Bertolotti (Sky Italia) introduced his view on the immersive media experience age.

Overall, the workshop was well attended and as mentioned above, MPEG is currently working on a new standards project related to immersive media. Currently, this project comprises five parts. The first part comprises a technical report describing the scope (incl. kind of system architecture), use cases, and applications. The second part is OMAF (see above) and the third/forth parts are related to immersive video and audio respectively. Part five is about point cloud compression.

For those interested, please check out the slides from industry representatives in this field and draw your own conclusions what could be interesting for your own research. I'm happy to see any reactions, hints, etc. in the comments..

Finally, let's have a look what happened related to MPEG-DASH, a topic with a long history on this blog.

MPEG-DASH and CMAF: Friend or Foe?

For MPEG-DASH and CMAF it was a meeting "in between" official standardization stages. MPEG-DASH experts are still working on the third edition which will be a consolidated version of the 2nd edition and various amendments and corrigenda. In the meantime, MPEG issues a white paper on the new features of MPEG-DASH which I would like to highlight here.

• Spatial Relationship Description (SRD): allows to describe tiles and region of interests for partial delivery of media presentations. This is highly related to OMAF and VR/360-degree video streaming.
• External MPD linking: this feature allows to describe the relationship between a single program/channel and a preview mosaic channel having all channels at once within the MPD.
• Period continuity: simple signaling mechanism to indicate whether one period is a continuation of the previous one which is relevant for ad-insertion or live programs.
• MPD chaining: allows for chaining two or more MPDs to each other, e.g., pre-roll ad when joining a live program.
• Flexible segment format for broadcast TV: separates the signaling of the switching points and random access points in each stream and, thus, the content can be encoded with a good compression efficiency, yet allowing higher number of random access point, but with lower frequency of switching points.
• Server and network-assisted DASH (SAND): enables asynchronous network-to-client and network-to-network communication of quality-related assisting information.
• DASH with server push and WebSockets: basically addresses issues related to HTTP/2 push feature and WebSocket.

CMAF issued a study document which captures the current progress and all national bodies are encouraged to take this into account when commenting on the Committee Draft (CD). To answer the question in the headline above, it looks more and more like as DASH and CMAF will become friends -- let's hope that the friendship lasts for a long time.

What else happened at the MPEG meeting?

• Committee Draft MORE (note: type in 'man more' on any unix/linux/max terminal and you'll get 'less - opposite of more';): MORE stands for “Media Orchestration” and provides a specification that enables the automated combination of multiple media sources (cameras, microphones) into a coherent multimedia experience. Additionally, it targets use cases where a multimedia experience is rendered on multiple devices simultaneously, again giving a consistent and coherent experience.
• Technical Report on HDR/WCG Video Coding: This technical report comprises conversion and coding practices for High Dynamic Range (HDR) and Wide Colour Gamut (WCG) video coding (ISO/IEC 23008-14). The purpose of this document is to provide a set of publicly referenceable recommended guidelines for the operation of AVC or HEVC systems adapted for compressing HDR/WCG video for consumer distribution applications
• CfP Point Cloud Compression (PCC): This call solicits technologies for the coding of 3D point clouds with associated attributes such as color and material properties. It will be part of the immersive media project introduced above.
• MPEG-H 3D Audio verification test report: This report presents results of four subjective listening tests that assessed the performance of the Low Complexity Profile of MPEG-H 3D Audio. The tests covered a range of bit rates and a range of “immersive audio” use cases (i.e., from 22.2 down to 2.0 channel presentations). Seven test sites participated in the tests with a total of 288 listeners.

The next MPEG meeting will be held in Hobart, April 3-7, 2017. Feel free to contact us for any questions or comments.