
Ali C. BegenÖzyeğin University · Department of Computer Science
Ali C. Begen
PhD in Electrical and Computer Engineering
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144
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Publications
Publications (144)
Adaptive bitrate (ABR) schemes enable streaming clients to adapt to time-varying network/device conditions for a stall-free viewing experience. Most ABR schemes use manually tuned heuristics or learning-based methods. Heuristics are easy to implement but do not always perform well, whereas learning-based methods generally perform well but are diffi...
A QUIC-based low-latency delivery solution for media ingest and distribution in browser and non-browser environments is currently being developed for various use cases such as live streaming, cloud gaming, remote desktop, videoconferencing, and eSports. Operating in an Hyptertext Transfer Protocaol (HTTP)/3 environment (i.e., using WebTransport in...
Media streaming over the Internet is dominated by Hypertext Transfer Protocol (HTTP) adaptive streaming solutions. These solutions typically host the required media files on multiple content delivery networks (CDNs). To avoid outages and performance problems, selecting the optimal CDN is an essential step in the media streaming workflow. Content st...
Smooth playback is critical for any streaming service. Naturally, viewers do not enjoy rebuffering events, but less frequent and shorter ones are preferred when they cannot be avoided. However, ensuring smoother playback becomes more challenging as more demanding types of services such as low-latency live (LLL) and 4K streaming become increasingly...
This paper highlights the current trends and the necessary research directions for achieving carbon-effective streaming services. Collaboration between the end-to-end delivery pipeline vendors is encouraged to design standards and technologies.
Omnidirectional MediA Format (OMAF) is the first worldwide virtual reality (VR) standard to store and distribute immersive media, completed in 2019. Later, in 2021, the second edition of this standard (OMAF v2) was published. The second edition kept all the features defined in the first OMAF edition while introducing some new ones, such as overlays...
Efficient use of available bandwidth is vital when streaming 360-degree videos as users rarely have enough bandwidth for a pleasant experience. A promising solution is the combination of viewport-dependent streaming using tiled video and rate adaptation, where the goal is to spend most of the available bandwidth for the viewport tiles. However, hea...
In Hypertext Transfer Protocol (HTTP) adaptive streaming, the client makes rate adaptation decisions based on the measured network bandwidth and buffer fullness. This simplifies the adaptation logic; however, it often produces noticeable quality fluctuations during the streaming session. With content-aware encoding (CAE), one can improve the visual...
With the introduction of HTTP/3 (H3) and QUIC at its core, there is an expectation of significant improvements in Web-based secure object delivery. As HTTP is a central protocol to the current adaptive streaming methods in all major streaming services, an important question is what H3 will bring to the table for such services. To answer this questi...
Measuring quality accurately and quickly (preferably in real time) when streaming 360-degree videos is essential to enhance the user experience. Most quality-of-experience (QoE) metrics have primarily used viewport quality as a simple surrogate for such experiences at a given time. While this baseline approach has been later augmented by some resea...
Bandwidth prediction is critical in any Real-time Communication (RTC) service or application. This component decides how much media data can be sent in real time. Subsequently, the video and audio encoder dynamically adapts the bitrate to achieve the best quality without congesting the network and causing packets to be lost or delayed. To date, sev...
Viewport-dependent delivery (VDD) is a technique to save network resources during the transmission of immersive videos. However, it results in a non-zero motion-to-high-quality delay (MTHQD), which is the delta time from the moment where the current viewport has at least one low-quality tile to when all the tiles in the new viewport are rendered in...
Streaming media has truly become one of the most popular applications on the Internet. Viewers are spoiled for choice, and content providers compete to provide the best viewer experience. Traditionally, it has been challenging for content providers to get deep insights into the performance of their large-scale streaming operations. A new standard,...
Our earlier Low-on-Latency (dubbed as LoL) solution offered an accurate bandwidth prediction and rate adaptation algorithm tailored for live streaming applications that needed an end-to-end latency of up to two seconds. While LoL was a significant step forward in multi-bitrate low-latency live streaming, further experimentation and testing showed t...
Technological improvements are rapidly ad-vancing holographic-type content distribution. Significantresearch efforts have been made to meet the low-latencyand high-bandwidth requirements set forward by interac-tive applications such as remote surgery and virtual reality.Recent research made six degrees of freedom (6DoF) forimmersive media possible,...
Technological improvements are rapidly advancing holographic-type content distribution. Significant research efforts have been made to meet the low latency and high bandwidth requirements set forward by interactive applications such as remote surgery and virtual reality. Recent research made six degrees of freedom (6DoF) for immersive media possibl...
Today's HTTP adaptive streaming solutions use a variety of algorithms to measure the available network bandwidth and predict its future values. Bandwidth prediction, which is already a difficult task, must be more accurate when lower latency is desired due to the shorter time available to react to bandwidth changes, and when mobile networks are inv...
HTTP adaptive streaming with chunked transfer encoding can offer low-latency streaming without sacrificing the coding efficiency. This allows media segments to be delivered while still being packaged. However, conventional schemes often make widely inaccurate bandwidth measurements due to the presence of idle periods between the chunks and hence th...
Enhancing user experience in streaming applications is an important problem. Delivering the best quality possible for the given network conditions is not an easy task. In the case of a streaming client running in a multi-homed network, this problem becomes more complicated. In the simplest form, one network can be picked randomly or based on some c...
Volumetric media has the potential to provide the six degrees of freedom (6DoF) required by truly immersive media. However, achieving 6DoF requires ultra-high bandwidth transmissions, which real-world wide area networks cannot provide today. Therefore, recent efforts have started to target efficient delivery of volumetric media, using a combination...
Universal media access (UMA) as proposed almost two decades ago is now reality. We can generate, distribute, share, and consume any media content, anywhere, anytime, and with/on any device. A technical breakthrough was the adaptive streaming over HTTP resulting in the standardization of MPEG Dynamic Adaptive Streaming over HTTP (DASH), which is now...
The dramatic growth of HTTP adaptive streaming (HAS) traffic represents a practical challenge for service providers in satisfying the demand from their customers. Achieving this in a network where multiple players share the network capacity has so far proved hard because of the bandwidth competition among the HAS players. This competition is exacer...
HTTP adaptive streaming with chunked transfer encoding can be used to offer low-latency streaming without sacrificing the coding efficiency. While this allows a media segment to be generated and delivered at the same time, which is critical in reducing the latency, the conventional bitrate adaptation schemes make often grossly inaccurate bandwidth...
The papers in this special issue focus on trustworthiness in multimedia communications. Recently, social multimedia content is being delivered to users with a high quality of experience (QoE) with the advance of multimedia technologies and social networks. However, as a huge amount of social users have various demands to exchange and share multimed...
Quick User Datagram Protocol (UDP) Internet Connections (QUIC) is an experimental and low‐latency transport protocol proposed by Google, which is still being improved and specified in the Internet Engineering Task Force (IETF). The viewer's quality of experience (QoE) in HTTP adaptive streaming (HAS) applications may be improved with the help of QU...
Past research has shown that concurrent HTTP adaptive streaming (HAS) players behave selfishly and the resulting competition for shared resources leads to underutilization or oversubscription of the network, presentation quality instability and unfairness among the players, all of which adversely impact the viewer experience. While coordination amo...
Video resolution changes in an HTTP adaptive streaming session may negatively affect the viewer's Quality of Experience. Our goal is, through encoding, to make such resolution changes less noticeable for the viewers. This can be achieved by taking video complexity features into account in the encoding process. In this paper, we compare Constant Bit...
In designing an HTTP adaptive streaming (HAS) system, the bitrate adaptation scheme in the player is a key component to ensure a good quality of experience (QoE) for viewers. We propose a new online reinforcement learning optimization framework, called ORL-SDN, targeting HAS players running in a software-defined networking (SDN) environment. We lev...
In this survey, we present state-of-the-art bitrate adaptation algorithms for HTTP adaptive streaming (HAS). As a key distinction from other streaming approaches, the bitrate adaptation algorithms in HAS are chiefly executed at each client, i.e., in a distributed manner. The objective of these algorithms is to ensure a high Quality of Experience (Q...
Streaming audio and video content currently accounts for the majority of the internet traffic and is typically deployed over the top of the existing infrastructure. We are facing the challenge of a plethora of media players and adaptation algorithms showing different behavior but lack a common framework for both objective and subjective evaluation...
Originally proposed by Google, QUIC is a low-latency transport protocol currently being developed and specified in the IETF. QUIC's low-latency, improved congestion control, multiplexing features are promising and may help improve viewer experience in HTTP adaptive streaming applications. To investigate what issues due to running HTTP over TCP can...
In streaming media, it is imperative to deliver a good viewer experience to preserve customer loyalty. Prior research has shown that this is rather difficult when shared Internet resources struggle to meet the demand from streaming clients that are largely designed to behave in their own self-interest. To date, several schemes for adaptive streamin...
This paper proposes a software defined networking based bandwidth broker solution for improving viewer experience for any type of content delivered to any type of consumer device using HTTP adaptive streaming (HAS) in a hybrid fiber coax network. This solution is designed to meet per-session and per-group quality-of-experience objectives, to avoid...
MPEG Dynamic Adaptive Streaming over HTTP (DASH) provides formats that are suitable to stream segmented media content over HTTP. DASH clients follow a client-pull paradigm by adapting their requests based on the available bandwidth and other local resources. This has proven to be easier to deploy over content delivery network infrastructure than se...
In this second issue of the Networking Standards Series, we are touching on an emerging topic for the consumers: immersive media. Today, more than two thirds of the content delivered on the Internet is related to traditional multimedia (streaming) and it is expected that it will be more than 80 percent by 2021 as immersive media applications and se...
HTTP adaptive streaming (HAS) is receiving much attention from both industry and academia as it has become the de facto approach to stream media content over the Internet. Recently, we proposed a streaming architecture called SDNDASH [1] to address HAS scalability issues including video instability, quality of experience (QoE) unfairness and networ...
The article in this special section focus on the market for new networking technologies. Networking technologies are advancing faster than ever before. Aspects driving this change in velocity is the need to support faster, more reliable, ubiquitous services with an ever-increasing scale over the communications infrastructure. This is causing a shif...
MPEG-Dynamic Adaptive Streaming over HTTP (DASH) provides formats that are suitable to stream media content over HTTP. Typically, the DASH client adaptively requests small chunks of media based on the available bandwidth and other resources. This client-pull technology has proven to be more flexible, firewall-friendly, and CDN-scalable than server-...
The articles in this special section discusses next generation broadcasting networks as it relates to the consumer communications markets.
For consumers, watching video over the Web is the most popular way to access free and premium content on connected devices. The underlying technology -- HTTP adaptive streaming -- is straightforward; however, due to quality fluctuations, it doesn't always result in a pleasant viewer experience. This can lead to dissatisfied consumers, which then le...
HTTP adaptive streaming (HAS) is being adopted with increasing frequency and becoming the de-facto standard for video streaming. However, the client-driven, on-off adaptation behavior of HAS results in uneven bandwidth competition and this is exacerbated when a large number of clients share the same bottleneck network link and compete for the avail...
MPEG DASH provides formats that are suitable to stream segmented media content over HTTP. DASH clients follow a client-pull paradigm by adapting their requests based on the available bandwidth and other local resources. This has proven to be easier to deploy over CDN infrastructure than server-push technologies. However, this decentralised nature i...
Recent years have witnessed the blooming of mobile devices and applications. Mobile users not only expect a faster broadband connection to access Internet and interact with each other, but also demand ubiquitous enjoying of video contents and services. However, this trend is seriously hindered by the fact that mobile devices have limited resources...
This theme is strongly reflected in the four articles we have selected for this edition of the Consumer Communications and Networking series. The theme includes the enhancement of network features as well as network extensions to cover an even larger area and to reach more people. Articles in this edition cover network topics including flow updates...
MPEG DASH provides formats that are suitable to stream media content over HTTP. Typically, the DASH client adaptively requests small chunks of media based on the available bandwidth and other resources. This client- pull technology has proven to be more flexible, firewall-friendly and CDN- scalable than server-push technologies. However, servic...
In conventional HTTP adaptive streaming (HAS), a video content is encoded into multiple representations, and each of these representations is temporally segmented into small pieces. A streaming client makes its segment selections among the available representations mostly according to the measured network bandwidth and buffer fullness. This greatly...
The last 15 years have heralded many developments and advances in consumer communications, from early developments of device-specific challenges in interoperability and configuration that are well captured by the concept of plug and play to a more recent emphasis on mobility and service personalization. The one constant technical challenge, and to...
In this tutorial we present state of the art and challenges ahead in over-the-top content delivery. It particular, the goal of this tutorial is to provide an overview of adaptive media delivery, specifically in the context of HTTP adaptive streaming (HAS) including the recently ratified MPEG-DASH standard. The main focus of the tutorial will be on...
A method is provided in one example embodiment and includes generating a bandwidth estimation for an adaptive bitrate (ABR) client; evaluating a current state of a buffer of the ABR client; and determining an encoding rate to be used for the ABR client based, at least, on the bandwidth estimation and the current state of the buffer. A fetch interva...
In one system embodiment, a first receive-and-process (RP) system and a second RP system, the first and second RP systems each configured to receive a first broadcast stream corresponding to a service, the broadcast stream comprising either a raw Internet protocol (IP) stream or a non-IP stream, and each further configured to derive a first Real-ti...
In one embodiment, a method that receives at a cache server device a request from a client device for a first representation of a content chunk; determines whether the first representation is available at the cache server device; responsive to determining that the first representation is available at the cache server device, provides the first repr...
A major theme in the consumer communications area has been networked homes. In the past this has often focused on networking consumer devices within a single home to offer added value or better control. Initially, these solutions were often closed and only worked with devices of a single manufacturer. Subsequently, this interworking has been extend...
This special issue is concerned with the latest developments in state-of-the-art adaptive media streaming technologies and applications.
Video streaming is a major source of Internet traffic today and usage continues to grow at a rapid rate. To cope with this new and massive source of traffic, ISPs use methods such as caching to reduce the amount of traffic traversing their networks and serve customers better. However, the presence of a standard cache server in the video transfer pa...