Researcher:
Civanlar, Mehmet Reha

Profile Picture
ORCID

Job Title

Faculty Member

First Name

Mehmet Reha

Last Name

Civanlar

Name

Name Variants

Civanlar, Mehmet Reha
Civanlar, Reha

Email Address

Birth Date

Filters

2003 - 200753

Advanced Search

Filter by

Settings

Researcher Of Publications: search.filters.isAuthorOfPublication.d8c4da65-4461-440f-992a-7f46b6bacf2b

Search Results

Now showing 1 - 10 of 53
  • Placeholder
    PublicationMetadata only
    Application QoS fairness in wireless video scheduling
    (Institute of Electrical and Electronics Engineers (IEEE), 2006) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Sunay, Mehmet Oğuz; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; 26207; 16372; N/A
    The video pre-roll delay for filling up the client buffer can not be too long for user utility and buffer limitations in wireless point-to-multipoint streaming systems. Cross-layer design that deals with both physical and application layer aspects jointly is necessary for this purpose. We present a cross-layer optimized multiuser video adaptation and user scheduling framework for wireless video communication, where Quality-of-Service (QoS) fairness among users is provided with maximum video quality and video throughput. Both protocol layers are jointly optimized using a single Multi-Objective Optimization (MOO) framework that aims to schedule the user with the least remaining playback time and the highest video throughput (delivered video seconds per transmission slot) with maximum video quality. Experiments carried out in the IS-856 (1×EV-DO) standard and ITU pedestrian and vehicular environments demonstrate the improvements over the state-of-the-art schedulers in terms of video QoS fairness, video quality and throughput. / İstemci arabelleğini doldurmak için videodan önce gösterilen reklam gecikmesi, kablosuz noktadan çok noktaya akış sistemlerinde kullanıcı yardımcı programı ve arabellek sınırlamaları için çok uzun olamaz. Bu amaç için hem fiziksel hem de uygulama katmanı özelliklerini birlikte ele alan çapraz katman tasarımı gereklidir. Kablosuz video iletişimi için, kullanıcılar arasında Hizmet Kalitesi (QoS) adaletinin maksimum video kalitesi ve video çıkışı ile sağlandığı, katmanlar arası optimize edilmiş çok kullanıcılı bir video uyarlaması ve kullanıcı planlama çerçevesi sunuyoruz. Her iki protokol katmanı, kullanıcıyı maksimum video kalitesiyle en az kalan oynatma süresi ve en yüksek video verimi (iletim yuvası başına iletilen video saniyesi) ile programlamayı amaçlayan tek bir Çok Amaçlı Optimizasyon (MOO) çerçevesi kullanılarak ortaklaşa optimize edilmiştir. IS-856 (lxEV-DO) standardında ve ITU yaya ve araç ortamlarında gerçekleştirilen deneyler, video QoS adaleti, video kalitesi ve verim açısından en son teknoloji zamanlayıcılara göre iyileştirmeler göstermektedir.
  • Placeholder
    PublicationMetadata only
    Optimal rate and input format control for content and context adaptive video streaming
    (IEEE, 2004) Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; N/A; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Özçelebi, Tanır; Faculty Member; Faculty Member; PhD Student; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; 26207; 16372; N/A
    A novel dynamic programming based technique for optimal selection of input video format and compression rate for video streaming based on "relevancy" of the content and user context is presented. The technique uses context dependent content analysis to divide the input video into temporal segments. User selected relevance levels assigned to these segments are used in formulating a constrained optimization problem, which is solved using dynamic programming. The technique minimizes a weighted distortion measure and the initial waiting time for continuous playback under maximum acceptable distortion constraints. Spatial resolution and frame rate of input video and the DCT quantization parameters are used as optimization variables. The technique is applied to encoding of soccer videos using an H.264 [1] encoder. The improvements obtained over a standard H.264 implementation are demonstrated by experimental results.
  • Placeholder
    PublicationMetadata only
    E_coach
    (IEEE, 2004) Department of Electrical and Electronics Engineering; Department of Computer Engineering; Civanlar, Mehmet Reha; Baykan, Eda; Faculty Member; Undergraduated Student; Department of Electrical and Electronics Engineering; Department of Computer Engineering; College of Engineering; College of Engineering; 16372; N/A
    We developed the necessary software to control the playback speed of exercise videos playing on a personal computer, using the heart rate of an individual performing the recorded exercise routine. Moderate exercise, at an appropriate heart rate, is widely regarded today as an excellent way to improve one's health when performed on a regular and frequent basis. One popular form of an indoor exercise program is to use a video "workout" program of aerobic exercise and/or weight training exercises. The "off-the-shelf" exercise videos, while they may target various fitness levels (such as "beginner", "regular", and "advanced"), cannot offer precise adjustments to address each user's current fitness level. The software developed allows for the playback of an exercise video to be adjusted to accommodate the fitness level of the individual user through a closed loop feedback mechanism. The project is being improved for logging and analyzing the performance of an individual who uses the system regularly and for exercise planning. The closed loop feedback mechanism that models the relationship between the heart rate and exercise level, is being improved with the experiments in which subjects incude fit people as well as ones who are sedementary. © 2004 IEEE.
  • Placeholder
    PublicationMetadata only
    A receiver-driven multicast framework for 3DTV transmission
    (Institute of Electrical and Electronics Engineers (IEEE), 2005) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Kurutepe, Engin; Civanlar, Mehmet Reha; Tekalp, Ahmet Murat; Master Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 16372; 26207
    Contemporary television and video experience is not interactive and mostly static. There is a demand for a real 3-D interactive experience which would allow users to view scenes through virtual cameras. Among other issues the amount of bandwidth required to transmit very large 3-D scene representations to end users is still an unsolved problem. In this paper we propose a novel networking scheme to enable users to automatically stream only the necessary parts of the 3-D representation to render the actual view. Our method also incorporates prediction of future views to prefetch streams which are likely to be needed in the near future as the view changes over time. / Güncel televizyon ve video deneyimi büyük ölçüde duruktur ve etkileşimli değildir. Ancak kullanıcıların sahneleri sanal kameralarla görmelerini sağlayacak gerçek 3-B etkileşimli deneyime ihtiyaç vardır. Çok büyük 3-B sahne gösterimlerinin son kullanıcılara iletimi için gerekli olan bant genişliği miktarı hala çözülememiş sorunlardan biridir. Biz bu makale ile kullanıcıların 3-B gösterimin sadece o andaki bakışlarını oluşturmak için gerekli olan kısımlarını duraksız iletim ile almalarını sağlayan bir ağ yöntemi öneriyoruz. Buna ek olarak kullanıcının bakışındaki değişikliklere göre gelecekte gerekli olabilecek veri katarlarını öngörerek alıp getirmeyi amaçlıyoruz.
  • Placeholder
    PublicationMetadata only
    Transport methods in 3DTV - a survey
    (IEEE-Inst Electrical Electronics Engineers Inc, 2007) Akar, Gözde B.; Fehn, Christoph; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; 26207; 16372
    We present a survey of transport methods for 3-D video ranging from early analog 3DTV systems to most recent digital technologies that show promise in designing 3DTV systems of tomorrow. Potential digital transport architectures for 3DTV include the DVB architecture for, broadcast and the Internet Protocol (IP) architecture for wired or wireless streaming. There are different multiview representation/compression methods for delivering the 3-D experience which provide a tradeoff between compression efficiency, random access to views, and ease of rate adaptation, including the "video plus-depth" compressed representation and various multiview video coding (MVC) options. Commercial activities using these representations in broadcast and IP streaming have emerged, and successful transport of such data has been reported. Motivated by the growing impact of the Internet protocol based media transport technologies, we focus on the ubiquitous Internet as the network infrastructure of choice for future 3DTV systems. Current research issues in unicast and multicast mode multiview video streaming include network protocols such as DCCP and peer-to-peer protocols, effective congestion control, packet loss protection and concealment, video rate adaptation, and network/service scalability. Examples of end-to-end systems for multiview video streaming have been provided.
  • Placeholder
    PublicationMetadata only
    A receiver-driven multicasting framework for 3dtv transmission
    (European Association for Signal Processing, 2005) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Kurutepe, Engin; Civanlar, Mehmet Reha; Tekalp, Ahmet Murat; Master Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 16372; 26207
    Contemporary television and video experience is not interactive and users have little or no choice over their viewing angle in the scenes they watch. There is a demand for a real 3-D interactive experience which would allow users to view scenes through virtual cameras chosen by their head and eye locations as in real life. However, among other issues the amount of bandwidth required to transmit very large Image Based Rendering (IBR) representations of the scene to end users is still an unsolved problem. In this paper we propose a novel networking scheme to enable users to automatically stream only the parts of the light field representation, which will be used to render the current viewpoint. The proposed system also incorporates prediction of future views to prefetch streams, which are likely to be needed in the near future as the viewpoint changes over time.
  • Placeholder
    PublicationMetadata only
    Scalable multiple description video coding with flexible number of descriptions
    (IEEE, 2005) N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Akyol, Emrah; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Master Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 26207; 16372
    Multiple description video coding mitigates the effects of packet losses introduced by congestion and/or bit errors. in this paper, we propose a novel multiple description video coding technique, based on fully scalable wavelet video coding, which allows post encoding adaptation of the number of descriptions, the redundancy level of each description, and bitrate of each description by manipulation of the encoded bitstream. We demonstrate that the proposed method provides excellent coding efficiency, outperforming most other multiple description methods proposed so far. We also provide experimental results to show that varying the number of descriptions according to network conditions is superior to using a fixed number of descriptions, by means of NS-2 network simulation of a peer-to-peer video streaming system.
  • Placeholder
    PublicationMetadata only
    Per-GOP bitrate adaptation for H.264 compressed video sequences
    (Springer-Verlag Berlin, 2006) De Martin, Juan Carlos; Department of Computer Engineering; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; De Vito, Fabio; Özçelebi, Tanır; Civanlar, Mehmet Reha; Tekalp, Ahmet Murat; Other; PhD Student; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 16372; 26207
    In video transmission over packet data networks, it may be desirable to adapt the coding rate according to bandwidth availability. Classical approaches to rate adaptation are bitstream switching, requiring the storage of several pre-coded versions of a video, or layered (scalable) video coding, which has coding efficiency and/or complexity penalties. In this paper we propose a new GOP-level rate adaptation scheme for a single stream, variable target bitrate H.264 encoder; this allows each group of pictures (GOP) to be encoded at a specified bitrate. We first compare the performance of the standard H.264 rate control algorithm with the proposed one in the case of constant target bitrate. Then, we present results on how close the new technique can track a specified per-GOP target bitrate schedule. Results show that the proposed approach can obtain the desired target rates with less than 5% error.
  • Placeholder
    PublicationMetadata only
    Per-GOP bitrate adaptation for 11.264 compressed video sequences
    (Springer, 2006) De Martin, J.C.; Department of Computer Engineering; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; De Vito, Fabio; Özçelebi, Tanır; Civanlar, Mehmet Reha; Tekalp, Ahmet Murat; Other; PhD Student; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 16372; 26207
    In video transmission over packet data networks, it may be desirable to adapt the coding rate according to bandwidth availability. Classical approaches to rate adaptation are bitstream switching, requiring the storage of several pre-coded versions of a video, or layered (scalable) video coding, which has coding efficiency and/or complexity penalties. In this paper we propose a new GOP-level rate adaptation scheme for a single stream, variable target bitrate H.264 encoder; this allows each group of pictures (GOP) to be encoded at a specified bitrate. We first compare the performance of the standard H.264 rate control algorithm with the proposed one in the case of constant target bitrate. Then, we present results on how close the new technique can track a specified per-GOP target bitrate schedule. Results show that the proposed approach can obtain the desired target rates with less than 5% error.
  • Placeholder
    PublicationMetadata only
    Delay-distortion optimization for content-adaptive video streaming
    (Institute of Electrical and Electronics Engineers (IEEE), 2007) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; PhD Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 26207; 16372
    We propose a new pre-roll delay-distortion optimization (DDO) framework that allows determination of the minimum pre-roll delay and distortion while ensuring continuous playback for on-demand content-adaptive video streaming over limited bitrate networks. The input video is first divided into temporal segments, which are assigned a relevance weight and a maximum distortion level, called relevance-distortion policy, which may be specified by the user. The system then encodes the input video according to the specified relevance-distortion policy, whereby the optimal spatial and temporal resolutions and quantization parameters, also called encoding parameters, are selected for each temporal segment. The optimal encoding parameters are computed using a novel, multi-objective optimization formulation, where a relevance weighted distortion measure and pre-roll delay are jointly minimized under maximum allowable buffer size, continuous playback, and maximum allowable distortion constraints. The performance of the system has been demonstrated for on-demand streaming of soccer videos with substantial improvement in the weighted distortion without any increase in pre-roll delay over a very low-bitrate network using AVC/H.264 encoding.