Mohammad Kazemi

University of Isfahan, Isfahan, Isfahan, Iran

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Publications (4)4.7 Total impact

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    ABSTRACT: Multiple Description Coding (MDC) is a technique where multiple streams from a video source are generated, each individually decodable and mutually refinable. MDC is a promising solution to overcome packet loss in video transmission over noisy channels, particularly for real-time applications in which retransmission of lost information is not practical. The error resiliency feature of MDC is achieved at the cost of redundancy, and the required amount of redundancy for each frame depends on the packet loss ratio and also the importance of the frame in the sequence. Due to the error propagation in video transmission over lossy channels, reference frames of a Group of Pictures (GOP) are more important for video reconstruction and, hence, need more redundancy to increase the chance of being received correctly. Therefore a channel adaptive optimization for frame-wise redundancy allocation is needed. In this paper, based on the difference of the side and central decoder outputs, the receiver side distortion is formulated and then used for optimization of a MDC scheme. The performance of the optimizer is verified by experimental results measured from JM 16.0, H.264/AVC reference software.
    Full-text · Article · Jun 2015 · Signal Processing Image Communication
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    ABSTRACT: Multiple description coding (MDC) is one of the promising solutions for live video delivery over lossy networks. In this paper, we present a review of MDC techniques based on their application domain and we explain their functionality, with the objective of giving enough insight to designers to decide which MDC scheme is best suited for their specific application based on requirements such as standard compatibility, redundancy tunability, complexity, and extendibility to n-description coding. The focus is mainly on video sources but image-based algorithms applicable to video are considered as well. We also cover the well-known and important problem of drift and solutions to avoid it.
    Full-text · Article · Jun 2013 · Multimedia Systems
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    ABSTRACT: Multiple description coding (MDC) is a technique where multiple streams from a source video are generated, each individually decodable and mutually refinable. MDC is a promising solution to overcome packet loss in video transmission over noisy channels, particularly for real-time applications in which retransmission of lost information is not practical. A problem with conventional MDC is that the achieved side distortion quality is considerably lower than single description coding (SDC) quality except at high redundancies which in turn leads to central quality degradation. In this paper, a new mixed layer MDC scheme is presented with no degradation in central quality, and providing better side quality (approximately as much as that of SDC) compared to conventional methods. Also, this property directly leads to higher average quality when delivering the video in lossy networks. For each discrete cosine transform coefficient, we generate two coefficients: base coefficient (BC) and enhancement coefficient which are combined together. When all descriptions are available, they are decomposed and decoded to achieve high quality video. When one description is not available, we use estimation to extract as much of the BC as possible from the received description. Simulation results show that the proposed scheme leads to an improved redundancy-rate-distortion performance compared to conventional methods. The algorithm is implemented in JM16.0 and its performance for two-description and four-description coding is verified by experiments.
    Full-text · Article · Mar 2012 · IEEE Transactions on Circuits and Systems for Video Technology
  • Mohammad Kazemi · Khosrow Sadeghi · Shervin Shirmohammadi
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    ABSTRACT: Multiple Description Coding (MDC) is a technique where multiple streams from a source are generated, each individually decodable and mutually refinable. In this paper, a new Mixed Layer MDC (MLMDC) scheme is presented which achieves a higher side quality compared to conventional MDCs. The improved side performance leads to higher average video quality at the receiver in lossy networks. For each DCT coefficient, we generate two coefficients: Base Coefficient (BC) and Enhancement Coefficient (EC) which are combined together. When all descriptions are available, they are decomposed and decoded to achieve high quality video. When one description is not available, we use estimation to extract as much of the BC as possible from the received description. The algorithm is implemented in JM16.0 and its performance for twodescription and four-description coding is verified by experiments.
    No preview · Conference Paper · Jul 2011