2 research outputs found
Error resilient stereoscopic video streaming using model-based fountain codes
Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent University, 2009.Thesis (Ph.D.) -- Bilkent University, 2009.Includes bibliographical references leaves 101-110.Error resilient digital video streaming has been a challenging problem since
the introduction and deployment of early packet switched networks. One of
the most recent advances in video coding is observed on multi-view video coding
which suggests methods for the compression of correlated multiple image
sequences. The existing multi-view compression techniques increase the loss sensitivity
and necessitate the use of efficient loss recovery schemes. Forward Error
Correction (FEC) is an efficient, powerful and practical tool for the recovery of
lost data. A novel class of FEC codes is Fountain codes which are suitable to be
used with recent video codecs, such as H.264/AVC, and LT and Raptor codes are
practical examples of this class. Although there are many studies on monoscopic
video, transmission of multi-view video through lossy channels with FEC have
not been explored yet. Aiming at this deficiency, an H.264-based multi-view
video codec and a model-based Fountain code are combined to generate an effi-
cient error resilient stereoscopic streaming system. Three layers of stereoscopic
video with unequal importance are defined in order to exploit the benefits of Unequal
Error Protection (UEP) with FEC. Simply, these layers correspond to intra frames of left view, predicted frames of left view and predicted frames of right
view. The Rate-Distortion (RD) characteristics of these dependent layers are de-
fined by extending the RD characteristics of monoscopic video. The parameters
of the models are obtained with curve fitting using the RD samples of the video,
and satisfactory results are achieved where the average difference between the
analytical models and RD samples is between 1.00% and 9.19%. An heuristic
analytical model of the performance of Raptor codes is used to obtain the residual
number of lost packets for given channel bit rate, loss rate, and protection
rate. This residual number is multiplied with the estimated average distortion
of the loss of a single Network Abstraction Layer (NAL) unit to obtain the total
transmission distortion. All these models are combined to minimize the end-toend
distortion and obtain optimal encoder bit rates and UEP rates. When the
proposed system is used, the simulation results demonstrate up to 2dB increase
in quality compared to equal error protection and only left view error protection.
Furthermore, Fountain codes are analyzed in the finite length region, and
iterative performance models are derived without any assumptions or asymptotical
approximations. The performance model of the belief-propagation (BP)
decoder approximates either the behavior of a single simulation results or their
average depending on the parameters of the LT code. The performance model of
the maximum likelihood decoder approximates the average of simulation results
more accurately compared to the model of the BP decoder. Raptor codes are
modeled heuristically based on the exponential decay observed on the simulation
results, and the model parameters are obtained by line of best fit. The analytical
models of systematic and non-systematic Raptor codes accurately approximate
the experimental average performance.Tan, A SerdarPh.D