&lt;title&gt;Mobile multimedia communications in a universal telecommunications network&lt;/title&gt;

Illgner, Klaus; Lappe, Dirk

doi:10.1117/12.206636

Cited by 21 publications

(11 citation statements)

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“…Another open-loop approach that has been proposed is the three-dimensional (3-D) subband coding approach of Chou and Chen [5]. Forward error correction (FEC) with unequal error protection (UEP) of the compressed bitstream is usually adopted in open-loop approaches to get reasonable performance on the wireless channel [6], [7].…”

Section: A Literaturementioning

confidence: 99%

Multiframe video coding for improved performance over wireless channels

Budagavi

Gibson

2001

IEEE Trans. on Image Process.

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We propose and evaluate a multi-frame extension to block motion compensation (BMC) coding of videoconferencing-type video signals for wireless channels. The multi-frame BMC (MF-BMC) coder makes use of the redundancy that exists across multiple frames in typical videoconferencing sequences to achieve additional compression over that obtained by using the single frame BMC (SF-BMC) approach, such as in the base-level H.263 codec. The MF-BMC approach also has an inherent ability of overcoming some transmission errors and is thus more robust when compared to the SF-BMC approach. We model the error propagation process in MF-BMC coding as a multiple Markov chain and use Markov chain analysis to infer that the use of multiple frames in motion compensation increases robustness. The Markov chain analysis is also used to devise a simple scheme which randomizes the selection of the frame (amongst the multiple previous frames) used in BMC to achieve additional robustness. The MF-BMC coders proposed are a multi-frame extension of the base level H.263 coder and are found to be more robust than the base level H.263 coder when subjected to simulated errors commonly encountered on wireless channels.

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Section: A Literaturementioning

confidence: 99%

Multiframe video coding for improved performance over wireless channels

Budagavi

Gibson

2001

IEEE Trans. on Image Process.

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“…In contrast to previous works based on unequal error protection [7,9,101, the scheme outlined in this paper From a general perspective, a H.263 bit stream consists of header bits and data bits. The fixed-length codewords of the header provide the exact locations of each frame and GOB, and information about image format, coding mode, and other important characteristics which have to be protected for the transmission over a noisy channel.…”

Section: Introductionmentioning

confidence: 95%

Error resilient transmission of H. 263 video for mobile communications

Abrardo

Barni

Garzelli

et al. 2001

Trans Emerging Tel Tech

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Automatic Repeat Request (ARQ) strategies reduce error propagation in low bitrate video transmission. However, retransmission of corrupted data introduces delay which may be critical in some practical applications. In such cases, only a FEC strategy is feasible at the expense of a significant increase of the overall transmission bit rate. In this paper, a strategy is proposed which instead of protecting the whole H.263 video stream, uses all the redundancy to protect the most important parts of the bit stream, i.e. GOB start codes. More specifically, the 22-bit-long start code used in the H.263 standard is replaced with longer Gold sequences which ensure a higher protection against noise. A different sequence is used for each GOB so that additional information can be obtained which can be used to improve the quality of the decoded sequence. The new technique is derived by assuming a slow-fading channel such as those encountered in pedestrian applications. Simulation results prove the effectiveness of the proposed technique with respect to classical FEC schemes in terms of PSNR and overall bit rate

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“…A plethora of video codecs have been proposed in the excellent special issues edited by Tzou reported promising results on adopting the H261 codec for wireless applications by invoking powerful signal processing and error-control techniques in order to remedy the inherent source coding problems due to stretching its application domain to hostile wireless environments. Further important contributions in the field were due to Chen et a1 [21], Illgner and Lappe [22] Zhang [23], Ibaraki, Fujimoto and Nakano [24], Watanabe et a1 [25] [29], but it incorporates a number of recent advances in the field, such as using half pixel resolution% in the motion compensation, or configuring the codec for a lower datarate or better error resilience. Furthermore, four so-called negotiable coding options were introduced, which are referred to in H.263 parlance as Unrestricted Motion Vectors, Syntax-based arithmetic coding, Advance prediction, and predicted-(P) as well as bi-directional ( B ) frames in order to improve the coding performance.…”

Section: Overview Of Video Codecsmentioning

confidence: 99%

Fixed‐rate video codecs for mobile radio systems

Streit

Hanzo

1997

Trans Emerging Tel Tech

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Abstract.A comparative study of arbitrarily programmable, but fixed-rate videophone codecs using quarter common intermediate format (QCIF) video sequences scanned at 10 frames/s is offered. In contrast to existing and forthcoming standard schemes, such as the H.261, H.263 and MPEG2, MPEG4 codecs, which rely on bandwidth-efficient but error-sensitive variable-length coding techniques combined with a complex self-descriptive bitstream structure, the proposed codecs exhibit a more robust, regular bitstream and a constant bitrate. Clearly, their philosophy is different from the above error-sensitive and variable-rate standard schemes, since these constant-rate codecs were designed to allow direct replacement of mobile radio voice codecs in second generation wireless systems, such as the Pan-European GSM, the American IS-54 and IS-95 as well as the Japanese systems, operating at 13, 8, 9.6 and 6.7 kbit/s, respectively. This philosophy can, however, be adopted to higherrate systems, such as the Digital European Cordless Telecommunications (DECT) and the Universal Mobile Telecommunications System (UMTS). The Type I codecs proposed benefit from invoking sophisticated compression technrqurs in order to achieve best video quality at a given bitrate. In contrast, the Type 2 schemes introduced maximise the codecs' error resilience at the cost of slightly reduced video quality under error-free conditions. Gain-cost quantised, tixed but arbitrarily programmable rate discrete cosine transformed (DCT) video codecs, vector-quantised (VQ) and quad-tree (QT) coded algorithms are proposed and their video quality, complexity. compression ratio and error resilience trade-offs are comparatively analysed under identical conditions. Finally, our candidate codecs are compared to the standard H261, H.263 and MPEG2 benchmark codecs. OVERVIEW OF VIDEO CODECSIn parallel to the rapid proliferation of multimedia communications services over fixed networks there is a growing demand for the added convenience of tetherless roaming. The earliest embodiment of the wireless multimedia communicator is expected to take the shape of a wireless videophone, which is likely to evolve from the family of the existing second generation mobile phones, such as the Pan-European GSM scheme [l] and video users can be accommodated by an additional speech channel. Furthermore, the codecs have to lend themselves to fixed, but programmable rate operation in the intelligent rnultimode terminals (IMTs) of the near future, which will allow tele-traffic or channel-quality motivated transceiver reconfiguration [8,9, 10, 11, 121.The theory and practice of image compression has been consolidated in a number of established monographs by Netravali and Haskell [ 131, Jain [14]

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<title>Mobile multimedia communications in a universal telecommunications network</title>

Cited by 21 publications

References 0 publications

Multiframe video coding for improved performance over wireless channels

Multiframe video coding for improved performance over wireless channels

Error resilient transmission of H. 263 video for mobile communications

Fixed‐rate video codecs for mobile radio systems

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