Wednesday, October 25, 2017

University Assistant (m/f)

The Alpen-Adria-Universität Klagenfurt announces the following job vacancy (in accordance with § 107 Abs. 1 Universitätsgesetz 2002):

University Assistant (m/f)
(fixed-term employment for the period of 4 years, 40 hours/week (Uni-KV: B1))

at the Faculty for Technical Sciences, Department for Computer Science. The monthly minimum salary for this position as stated in the collective agreement and according to the classification scheme is €2.731 (pre-tax, 14 x per year), but may be higher due to previous employment periods eligible for inclusion and other earnings and remunerations. Estimated commencement of duties will be the 1st of March, 2018.

Your duties:
  • Independent scientific research with the goal to obtain the conferral of a doctorate
  • Collaboration at the department within the research group “distributed systems” in terms of research and teaching
  • Independent scientific research within the field of distributed systems
  • Participation at the students’ counselling
  • Collaboration at administrative tasks within the department and university committees
  • Collaboration at public relations activities within the institute and faculty

The research group “Distributed Systems” does its research within the field of scientific high-performance computing, cloud computing and multimedia systems. The goal is to publish in international, high quality professional journals and conference transcripts and to cooperate with various commercial partners. With regard to teaching, additional fields such as computer networks, operation systems, distributed systems and compiler construction are covered by our research group.

Your profile:
  • Master or diploma degree of Technical Science in the field of Computer Science, completed at a domestic or foreign university (with good final degrees)
  • Excellent knowledge and experience in: high-performance computing, cloud-computing, virtualisation, big data, energy efficiency
  • Fluency in English, both in written and oral form

All relevant documents for the application (including copies of all school certificates and performance records) have to be submitted via the online application form of the University of Klagenfurt no later than the 8th of November, mentioning reference number 607/17.

Desirable qualifications are:
  • Fluency in German, both in written and oral form
  • Excellent programming skills, especially C++ and Java
  • Experience in handling OpenStack
  • Relevant international and practical work experience
  • Social and communicative competences and ability to work in a team
  • Experience with university teaching and research activities

The goal of the position is to equip graduates of a master or diploma programme with the necessary technical and scientific training to complete a doctorate or PhD. In Technical Sciences. Applications of scientists already holding such degree can therefore not be taken into further consideration.

The University of Klagenfurt lays special emphasis on increasing the number of women in senior and in academic positions and therefore strongly invites qualified women to apply for this position. In case of equal qualifications, female applicants will receive preferential consideration.

Furthermore, persons with disabilities or chronic illnesses who meet the required qualification criteria are also explicitly invited to apply for the position.

General information for applicants:

Additional information regarding the research group “Distributed Multimedia Systems” can be found online ( or by phone +43-463-2700-3611 (Univ.-Prof. DI Dr. Radu Prodan).

The University of Klagenfurt cannot refund any travel or accommodation expenses that arises in connection with the admission procedure.

Saturday, October 14, 2017

Happy World Standards Day 2017

Today on October 14 we celebrate the World Standards Day which is a good opportunity to review how standards impact our everyday's life. In fact, many standards help me creating this blog post ranging from web standards (W3C), communication standards (IETF, ITU), and standards defining representation formats (e.g., JPEG, MPEG).

Perhaps you are wondering how such standards are created. In MPEG, for example and in a nutshell, new work items are proposed and discussed within the requirements subgroup, which typically issues a requirements document followed up by a call for proposal. The responses to this call are discussed and evaluated according to predefined criteria and adopted into a working draft. Once the working draft becomes mature, MPEG may decide to issue a Committee Draft (CD), which goes out to national bodies for ballot. If national bodies agree on the CD, which could include comments on how to improve it, the next stage would be Draft International Standard (DIS) followed up Final Draft International Standard (FDIS), each accompanied by a ballot including comments. At FDIS stage mainly yes|no vote is allowed and only pure editorial comments can be integrated before going to International Standard (IS), which is when the standard is finally published. [note: sometimes it's a bit more complicated but this is another story - for the interested reader, I've documented the process when working on MPEG-DASH here]

This may sound like a very boring process but it's also possible to win Engineering Emmy Awards like HEVC did very recently, where also Leonardo Chiariglione received the Charles F. Jenkins Lifetime Achievement Award (see his response to this award here). 

In this context, I often quote the following xkcd comic which shows two sides of the coin. First, the obvious one where one should indeed not create the 15th competing standards, which one may think it's easy but it isn't although there's also a positive aspect about this (see at the end of this blog post). Second, standards should only define the minimum to enable interoperability and leave out enough space for innovation and competition. However, it's not always clear from the beginning, where to draw the line in order to become a successful standard.
In the past couple of years I was heavily involved in the standardization of MPEG-DASH. In the beginning we've been in the situation with multiple competing formats (Adobe HDS, Apple HLS, Microsoft Smooth Streaming, etc.). MPEG-DASH was finally adopted by Adobe and Microsoft, leaving HLS as competing format/standard (i.e., informational RFC 8216) which now utilizes MPEG's Common Media Application Format (CMAF) to allow a common media segment format to be used by both DASH and HLS. Thus, we did not create the 15th competing standard and DASH/HLS/CMAF is an important step towards reducing market fragmentation although it's not yet the end of the path.

I'd like to conclude with two quotes related to standards. One is from one of my professor at university who was saying "if you have sleeping problems, read a standard", which is true - they are boring to read for an outsider - but it's exciting to work on standards as you basically define the path for future products and services. Finally, my favorite quote goes back to Andrew S. Tanenbaum's book on computer networks: "The nice thing about standards is that you have so many to choose from" which I interpret as a positive statement as competition leads to innovation which eventually leads to innovative products and services - that's what we want.

In this spirit: Happy World Standards Day!

Wednesday, September 13, 2017

Packet Video Workshop 2018

23rd Packet Video Workshop 2018
June 12, 2018, Amsterdam, The Netherlands
(co-located with ACM MMSys'18)

Workshop Co-Chairs
  • Ali C. Begen, Ozyegin University / Networked Media, Turkey (ali.begen at
  • Christian Timmerer, Alpen-Adria-Universität Klagenfurt / Bitmovin Inc., Austria (christian.timmerer at
Workshop TPC Co-Chairs
  • Roger Zimmermann, National University of Singapore (NUS), Singapore (rogerz at
  • Thomas Schierl, Fraunhofer Heinrich Hertz Institute (HHI), Germany (thomas.schierl at
The 23rd Packet Video Workshop (PV 2018) is devoted to presenting technological advancements and innovations in video and multimedia transmission over packet networks. The workshop provides a unique venue for people from the media coding and networking fields to meet, interact and exchange ideas. Its charter is to promote the research and development in both established and emerging areas of video streaming and multimedia networking. PV 2018 will be held in Amsterdam on June 12th. The workshop will be a single-track event and welcomes paper submissions from both cutting-edge research, and business and consumer applications. PV 2018 will be co-located with ACM MMSys, NOSSDAV, NetGames and MMVE.

PV 2018 seeks papers in all areas of media delivery over current IP and future networks. Authors are especially encouraged to submit papers with real-world experimental results and datasets.

Topics of interest include (but are not limited to)
  • Adaptive media streaming, and content storage, distribution and delivery
  • Network-distributed video coding and network-based media processing
  • Next-generation/future video coding, point cloud compression
  • Audiovisual communication, surveillance and healthcare systems
  • Wireless, mobile, IoT, and embedded systems for multimedia applications
  • Future media internetworking: information-centric networking and 5G
  • Immersive media: virtual reality (VR), augmented reality (AR), 360° video and multi-sensory systems, and its streaming
  • Machine learning in media coding and streaming systems
  • Standardization: DASH, MMT, CMAF, OMAF, MiAF, WebRTC, MSE, EME, WebVR, Hybrid Media, WAVE, etc.
  • Applications: social media, game streaming, personal broadcast, healthcare, industry 4.0, education, transportation, etc.
Important dates
  • Submission deadline: March 1, 2018
  • Acceptance notification: April 9, 2018
  • Camera-ready deadline: April 19, 2018

Submission instructions
Prospective authors are invited to submit an electronic version of full papers, in PDF format, up to six printed pages in length (double column ACM conference format) at the PV 2018 Web site. The authors are also encouraged to regularly check the PV 2018 web site for the latest information and updates. The proceedings will be published by ACM Digital Library.

Monday, September 4, 2017

MPEG news: a report from the 119th meeting, Turin, Italy

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.

The MPEG press release comprises the following topics:
  • Evidence of New Developments in Video Compression Coding
  • Call for Evidence on Transcoding for Network Distributed Video Coding
  • 2nd Edition of Storage of Sample Variants reaches Committee Draft
  • New Technical Report on Signalling, Backward Compatibility and Display Adaptation for HDR/WCG Video Coding
  • Draft Requirements for Hybrid Natural/Synthetic Scene Data Container

Evidence of New Developments in Video Compression Coding

At the 119th MPEG meeting, responses to the previously issued call for evidence have been evaluated and they have all successfully demonstrated evidence. The call requested responses for use cases of video coding technology in three categories:
  • standard dynamic range (SDR) — two responses;
  • high dynamic range (HDR) — two responses; and
  • 360° omnidirectional video — four responses.
The evaluation of the responses included subjective testing and an assessment of the performance of the “Joint Exploration Model” (JEM).

The results indicate significant gains over HEVC for a considerable number of test cases with comparable subjective quality at 40-50% less bit rate compared to HEVC for the SDR and HDR test cases with some positive outliers (i.e., higher bit rate savings). Thus, the MPEG-VCEG Joint Video Exploration Team (JVET) concluded that evidence exists of compression technology that may significantly outperform HEVC after further development to establish a new standard. As a next step, the plan is to issue a call for proposals at 120th MPEG meeting (October 2017) and responses expected to be evaluated at the 122th MPEG meeting (April 2018).

We already witness an increase of research articles addressing video coding technologies with capabilities beyond HEVC which will further increase in the future. The main driving force is over the top (OTT) delivery which calls for more efficient bandwidth utilization. However, competition is also increasing with the emergence of AV1 of AOMedia and we may observe also an increasing number of articles in that direction including evaluations thereof. An interesting aspect is also that the number of use cases is also increasing (e.g., see different categories above), which adds further challenges to the "complex video problem".

Call for Evidence on Transcoding for Network Distributed Video Coding

The call for evidence on transcoding for network distributed video coding targets interested parties possessing technology providing transcoding of video at lower computational complexity than transcoding done using a full re-encode. The primary application is adaptive bitrate streaming where a highest bitrate stream is transcoded into lower bitrate streams. It is expected that responses may use “side streams” (or side information, some may call it metadata) accompanying the highest bitrate stream to assist in the transcoding process. MPEG expects submissions for the 120th MPEG meeting where compression efficiency and computational complexity will be assessed.

Transcoding has been discussed already for a long time and I can certainly recommend this article from 2005 published in the Proceedings of the IEEE. The question is, what is different now, 12 years later, and what metadata (or side streams/information) is required for interoperability among different vendors (if any)?

A Brief Overview of Remaining Topics...

  • The 2nd edition of storage of sample variants reaches Committee Draft and expands its usage to MPEG-2 transport stream whereas the first edition primarily focused on ISO base media file format.
  • The new technical report for high dynamic range (HDR) and wide colour gamut (WCG) video coding comprises a survey of various signaling mechanisms including backward compatibility and display adaptation.
  • MPEG issues draft requirements for a scene representation media container enabling the interchange of content for authoring and rendering rich immersive experiences which is currently referred to as hybrid natural/synthetic scene (HNSS) data container.

Other MPEG (Systems) Activities at the 119th Meeting

DASH is in fully maintenance mode as only minor enhancements/corrections have been discussed including contributions to conformance and reference software. The omnidirectional media format (OMAF) is certainly the hottest topic within MPEG systems which is actually between two stages (i.e., between DIS and FDIS) and, thus, a study of DIS has been approved and national bodies are kindly requested to take this into account when casting their votes (incl. comments). The study of DIS comprises format definitions with respect to coding and storage of omnidirectional media including audio and video (aka 360°). The common media application format (CMAF) has been ratified at the last meeting and awaits publications by ISO. In the meantime CMAF is focusing on conformance and reference software as well as amendments regarding various media profiles. Finally, requirements for a multi-image application format (MiAF) are available since the last meeting and at the 119th MPEG meeting a work draft has been approved. MiAF will be based on HEIF and the goal is to define additional constraints to simplify its file format options.

We have successfully demonstrated live 360 adaptive streaming as described here but we expect various improvements from standards available and under development of MPEG. Research aspects in these areas are certainly interesting in the area of performance gains and evaluations with respect to bandwidth efficiency in open networks as well as how these standardization efforts could be used to enable new use cases. 

Publicly available documents from the 119th MPEG meeting can be found here (scroll down to the end of the page). The next MPEG meeting will be held in Macau, China, October 23-27, 2017. Feel free to contact me for any questions or comments.

Monday, July 24, 2017

IEEE ICME 2017: Keynote at Workshop on Mobile Multimedia Computing, Hong Kong, Jul 14, 2017

Titel: Dynamic Adaptive Streaming over HTTP: Overview, State-of-the-Art, and Challenges

Abstract: 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% by 2020. The technology used for such services is commonly referred to as Dynamic adaptive streaming over HTTP and is widely adopted by various platforms such as YouTube, Netflix, Flimmit, etc. thanks to the standardization of MPEG-DASH. This presentation provides an overview of the MPEG-DASH standard, various implementation options - specifically on informative aspects -, and reviews the work-in-progress and future research directions.

Bio: Christian Timmerer is an Associate Professor with Alpen-Adria-Universität Klagenfurt, Austria, and his research focus is on immersive multimedia communication, streaming, adaptation, and quality of experience. He has authored over 150 publications in his research area and was the General Chair of WIAMIS 2008, QoMEX 2013, and ACM MMSys 2016. He participated in several EC-funded projects, notably, DANAE, ENTHRONE, P2P-Next, ALICANTE, SocialSensor, and the COST Action IC1003 QUALINET. He also participated in ISO/MPEG work for several years, notably, in the areas of MPEG-21, MPEG-M, MPEG-V, and MPEG-DASH. He is a Co-Founder of Bitmovin and CIO | Head of Research and Standardization.


Thursday, July 13, 2017

DASH-IF awarded Grand Challenge on Dynamic Adaptive Streaming over HTTP at IEEE ICME 2017

Hong Kong, July 12, 2017

Real-time entertainment services such as streaming video and audio are currently accounting for more than 70% of the Internet traffic during peak hours. Interestingly, these services are all delivered over-the-top (OTT) of the existing networking infrastructure using the Hypertext Transfer Protocol (HTTP). The MPEG Dynamic Adaptive Streaming over HTTP (DASH) standard enables smooth multimedia streaming towards heterogeneous devices.

The aim of the DASH-IF Grand Challenge on Dynamic Adaptive Streaming over HTTP at IEEE ICME 2017 is to solicit contributions addressing end-to-end delivery aspects that will help improve the QoE while optimally using the network resources at an acceptable cost. Such aspects include, but are not limited to, content preparation for adaptive streaming, delivery in the Internet and streaming client implementations. A special focus of 2017’s grand challenge will be related to virtual reality applications and services including 360 degree videos.

We received the following submissions, which have been evaluated by DASH-IF members:
  • "Content Preparation and Cross-Device Delivery of 360° Video with 4k Field of View Using DASH" by Louay Bassbouss, Stefan Pham, Stephan Steglich, Martin Lasak
  • "A Hybrid P2P/Multi-Source Quality-Adaptive Live-Streaming Solution for high end-user's QoE" by Joachim Bruneau-Queyreix, Mathias Lacaud, Daniel Negru
  • "Efficient content preparation and distribution of 360VR sequences using MPEG-DASH technology" by Cesar Diaz, Julian Cabrera, Marta Orduna, Lara Munoz, Pablo Perex, Narciso Garcia
  • "Optimal Viewport Adaptive Streaming for 360-Degree Videos" by Zhimin Xu, Lan Xie, Xinggong Zhang, Han Hu, Yixuan Ban, Zongming Guo
The winner will be awarded  €750 and the runner-up €250.

Each submission has been presented at IEEE ICME 2017 within an oral session, which was attended very well. We've also seen interesting demos after all submissions have been presented.


This year's award goes to the following papers:

WINNER: "A Hybrid P2P/Multi-Source Quality-Adaptive Live-Streaming Solution for high end-user's QoE" by Joachim Bruneau-Queyreix, Mathias Lacaud, Daniel Negru
C. Timmerer (left), Joachim Bruneau-Queyreix (middle), Axel Becker-Lakus (right)

RUNNER-UP: "Optimal Viewport Adaptive Streaming for 360-Degree Videos" by Zhimin Xu, Lan Xie, Xinggong Zhang, Han Hu, Yixuan Ban, Zongming Guo
C. Timmerer (left), Zongming Guo (middle), Axel Becker-Lakus (right)

We would like to congratulate all winners and hope seeing you next year at IEEE ICME 2018.

Photos by Cigdem Turan (PolyU, Hong Kong).

Sunday, June 25, 2017

DASH-IF awarded Excellence in DASH award at ACM MMSys 2017

Taipei, Taiwan, June 21, 2017.

The DASH Industry Forum Excellence in DASH Award at ACM MMSys 2017 acknowledges papers substantially addressing MPEG-DASH as the presentation format and are selected for presentation at ACM MMSys 2017. Preference is given to practical enhancements and developments which can sustain future commercial usefulness of DASH. The DASH format used should conform to the DASH-IF Interoperability Points as defined by It is a financial prize as follows: First place – €1000; Second place – €500; and Third place – €250. The winners are chosen by a DASH Industry Forum appointed committee and results are final.

Viswanathan (Vishy) Swaminathan 

This year's award goes to the following papers
1. Ahmed H. Zahran, Jason J. Quinlan, K. K. Ramakrishnan, and Cormac J. Sreenan. 2017. SAP: Stall-Aware Pacing for Improved DASH Video Experience in Cellular Networks. In Proceedings of the 8th ACM on Multimedia Systems Conference (MMSys'17). Taiwan, Taipei, June 2017.
Vishy (left), Ahmed H. Zahran (right)
2. Jan Willem Kleinrouweler, Britta Meixner, and Pablo Cesar. 2017. Improving Video Quality in Crowded Networks Using a DANE. In Proceedings of the 27th Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV'17). Taiwan, Taipei, June 2017.
Jan Willem Kleinrouweler (left), Vishy (right)
3. Mario Graf, Christian Timmerer, and Christopher Mueller. 2017. Towards Bandwidth Efficient Adaptive Streaming of Omnidirectional Video over HTTP: Design, Implementation, and Evaluation. In Proceedings of the 8th ACM on Multimedia Systems Conference (MMSys'17). Taiwan, Taipei, June 2017.
Vishy (left), Christian Timmerer (right)

We would like to congratulate all winners and hope seeing you next year at ACM MMSys 2018.