G. Cote

University of British Columbia - Vancouver, Vancouver, British Columbia, Canada

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Publications (11)15.82 Total impact

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    ABSTRACT: We describe an effective method for increasing error resilience of video transmission over bit error prone networks. Rate-distortion optimized mode selection and synchronization marker insertion algorithms are introduced. The resulting video communication system takes into account the channel condition and the error concealment method used by the decoder, to optimize video coding mode selection and placement of synchronization markers in the compressed bit stream. The effects of mismatch between the parameters used by the encoder and the parameters associated with the actual channel condition and the decoder error concealment method are evaluated. Results for the binary symmetric channel and wideband code division multiple access mobile network models are presented in order to illustrate the advantages of the proposed method
    IEEE Journal on Selected Areas in Communications 07/2000; · 3.12 Impact Factor
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    ABSTRACT: We present an efficient computation constrained block-based motion vector estimation algorithm for low bit rate video coding that yields good tradeoffs between motion estimation distortion and number of computations. A reliable predictor determines the search origin, localizing the search process. An efficient search pattern exploits structural constraints within the motion field. A flexible cost measure used to terminate the search allows simultaneous control of the motion estimation distortion and the computational cost. Experimental results demonstrate the viability of the proposed algorithm in low bit rate video coding applications. The resulting low bit rate video encoder yields essentially the same levels of rate-distortion performance and subjective quality achieved by the UBC H.263+ video coding reference software. However, the proposed motion estimation algorithm provides substantially higher encoding speed as well as graceful computational degradation capabilities
    IEEE Transactions on Image Processing 01/2000; · 3.20 Impact Factor
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    ABSTRACT: We present a semi-fixed-length motion vector coding method for H.263-based low bit rate video compression. The method exploits structural constraints within the motion field. The motion vectors are encoded using semi-fixed-length codes, yielding essentially the same levels of rate-distortion performance and subjective quality achieved by H.263's Huffman-based variable length codes in a noiseless environment. However, such codes provide substantially higher error resilience in a noisy environment
    IEEE Transactions on Image Processing 11/1999; · 3.20 Impact Factor
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    ABSTRACT: A standard-based video communication system combining video coding, packetization, and transport protocol environment is introduced. Rather than focusing on the specific areas mentioned above, the strength of the introduced concept lies in the novel combination of the various tools, especially in a rate-distortion optimized H.263 video coder that takes packet loss into account, and the packetization based on the Internet RFC2429. Together, both mechanisms form a powerful platform for low-latency, RTP-based video transmission in packet lossy environments with typically large packet sizes, and packet loss rates of up to 20%
    Electrical and Computer Engineering, 1999 IEEE Canadian Conference on; 02/1999
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    ABSTRACT: In this paper, we describe an effective method for increasing error resilience of video transmission over bit error prone networks. Rate-distortion optimized mode selection and synchronization marker insertion algorithms are introduced. The resulting video communication system takes into account the channel condition and the error concealment method used by the decoder, to optimize video coding mode selection and placement of synchronization markers in the compressed bit stream. Results for the binary symmetric channel and wideband code division multiple access mobile network models are presented in order to illustrate the advantages of the proposed method
    Image Processing, 1999. ICIP 99. Proceedings. 1999 International Conference on; 02/1999
  • Guy Côté, Faouzi Kossentini
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    ABSTRACT: Reliable transmission of compressed video in a packet lossy environment cannot be achieved without error recovery mechanisms. We describe an effective method for increasing error resilience of video transmission over packet lossy networks such as the Internet. Intra coding (without reference to a previous picture) is a well-known technique for eliminating temporal error propagation in a predictive video coding system. Randomly intra coding of blocks increases error resilience to packet loss. However, when the error concealment used by the decoder is known, intra encoding following a method that optimizes the tradeoffs between compression efficiency and error resilience is a better alternative. In this paper, we present a rate-distortion optimized mode selection method for packet lossy environments that takes into account the network conditions and the error concealment method used at the decoder. We present results for different packet loss rates and typical packet sizes of the Internet, that illustrate the advantages of the proposed method.
    Signal Processing Image Communication 01/1999; · 1.29 Impact Factor
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    ABSTRACT: The emerging ITU-T H.263+ low bit-rate video coding standard is version 2 of the draft international standard ITU-T H.263. In this paper, we discuss this emerging video coding standard and present compression performance results based on our public domain implementation of H.263+
    Data Compression Conference, 1998. DCC '98. Proceedings; 12/1998
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    ABSTRACT: We discuss the ITU-T H.263+ (or H.263 Version 2) low-bit-rate video coding standard. We first describe, briefly, the H.263 standard including its optional modes. We then address the 12 new negotiable modes of H.263+. Next, we present experimental results for these modes, based on our public-domain implementation (http:ilspmg.ece.ubc.ca). Tradeoffs among compression performance, complexity, and memory requirements for the H.263+ optional modes are discussed. Finally, results for mode combinations are presented
    IEEE Transactions on Circuits and Systems for Video Technology 12/1998; · 1.82 Impact Factor
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    ABSTRACT: In this paper, we propose an e#cient motion vector estimation and coding method for H.263-based low bit rate video compression. The method exploits structural constraints within the motion #eld. The same H.263 median predictor is used to localize motion estimation, which is directed to the best motion vectors by employing a computation-constrained layered search technique. Moreover, the localized motion #eld is encoded using semi-#xedlength codes. The resulting low bit rate video encoder yields essentially the same levels of rate-distortion performance and subjective qualityachieved byTelenor's implementation of the ITU TMN5 model. However, our motion vector estimation and coding method provides for substantially higher encoding speed and channel error robustness. # This work was supported by the Natural Sciences and Engineering Research Council of Canada. 1 1 Introduction Very low bit rate video compression techniques are becoming increasingly important due to present and...
    09/1998;
  • IEEE Transactions on Image Processing 01/1997; · 3.20 Impact Factor
  • S. Wenger, G. Cote