Çankaya GCRIS Standart veritabanının içerik oluşturulması ve kurulumu Research Ecosystems (https://www.researchecosystems.com) tarafından devam etmektedir. Bu süreçte gördüğünüz verilerde eksikler olabilir.

Browsing by Author "Tolun, M."

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    Conference Object
    Citation - Scopus: 1
    Hierarchical SNR Scalable Video Coding with Adaptive Quantization for Reduced Drift Error
    (SciTePress, 2015) Choupani, R.; Wong, S.; Tolun, M.
    In video coding, dependencies between frames are being exploited to achieve compression by only coding the differences. This dependency can potentially lead to decoding inaccuracies when there is a communication error, or a deliberate quality reduction due to reduced network or receiver capabilities. The dependency can start at the reference frame and progress through a chain of dependent frames within a group of pictures (GOP) resulting in the so-called drift error. Scalable video coding schemes should deal with such drift errors while maximizing the delivered video quality. In this paper, we present a multi-layer hierarchical structure for scalable video coding capable of reducing the drift error. Moreover, we propose an optimization to adaptively determine the quantization step size for the base and enhancement layers. In addition, we address the trade-off between the drift error and the coding efficiency. The improvements in terms of average PSNR values when one frame in a GOP is lost are 3.70(dB) when only the base layer is delivered, and 4.78(dB) when both the base and the enhancement layers are delivered. The improvements in presence of burst errors are 3.52(dB) when only the base layer is delivered, and 4.50(dB) when both base and enhancement layers are delivered. Copyright © 2015 SCITEPRESS - Science and Technology Publications All rights reserved.
  • Thumbnail Image
    Conference Object
    Citation - Scopus: 0
    Optimized Multiple Description Coding for Temporal Video Scalability
    (Springer Verlag, 2013) Choupani, R.; Wong, S.; Tolun, M.
    The vast application of video streaming over the Internet requires video adaptation to the fluctuations of the available bandwidth, and the rendering capabilities of the receiver device. On the other hand, the available video coding standards are designed for optimum bit rate which makes them susceptible to packet losses. A combination of video adaptation methods and error resilient methods can make the video stream more robust against networking problems. In this paper, an optimization for combining scalable video coding with multiple description coding schemes have been proposed. Our proposed method is capable of creating balanced descriptions with optimum coding efficiency.
  • Thumbnail Image
    Conference Object
    Citation - Scopus: 3
    Scalable video transmission over unreliable networks using multiple description wavelet coding
    (2011) Choupany, R.; Wong, S.; Tolun, M.; 1863
    Scalable video coding (SVC) and multiple description coding (MDC) are the two different adaptation schemes for video transmission over heterogenous and best-effort networks such as the Internet. We present a new approach to combine the advantages of SVC and MDC to provide reliable video communication over a wider range of communication networks and/or satisfy application requirements. Our proposed method utilizes 3D discrete wavelet transform and a modified embedded zero tree data structure to group the coefficients in different descriptions. The proposed method reduces the impact of the drift error by organizing the frames in a hierarchical structure. © 2011 AICIT.