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Etude et optimisation d’un système de vidéotransmission conjoint Source-Canal basé « SoftCast »

Abstract : Linear video coding (LVC) schemes have recently demonstrated a high potential for delivering video content over challenging wireless channels. SoftCast represents the pioneer of the LVC schemes. Different from current video transmission standards and particularly useful in broadcast situation, SoftCast is a joint source-channel coding system where pixels are processed by successive linear operations (DCT transform, power allocation, quasi-analog modulation) and directly transmitted without quantization or coding (entropic or channel). This allows to provide a received video quality directly proportional to the transmission channel quality, without any feedback information, while avoiding the complex adaptation mechanisms of conventional schemes. A first contribution of this thesis is the study of the end-to-end performances of SoftCast. Theoretical models are thus proposed taking into account the bandwidth constraints of the application, the power allocation, as well as the type of decoder used at the reception (LLSE, ZF). Based on a subjective test campaign, a second part concern an original study of the video quality and specific artifacts related to SoftCast. In a third part, preprocessing methods are proposed to increase the received quality in terms of PSNR scores with an average gain of 3 dB. Finally, an adaptive algorithm modifying the size of the group of pictures (GoP) according to the characteristics of the transmitted video content is proposed. This solution allows to obtain about 1 dB additional gains in terms of PSNR scores.
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Contributor : Anthony Trioux <>
Submitted on : Monday, February 24, 2020 - 11:27:54 AM
Last modification on : Wednesday, October 14, 2020 - 3:48:29 AM
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  • HAL Id : tel-02483990, version 1


Anthony Trioux. Etude et optimisation d’un système de vidéotransmission conjoint Source-Canal basé « SoftCast ». Traitement du signal et de l'image [eess.SP]. IEMN-DOAE (Université Polytechnique Hauts-de-France), 2019. Français. ⟨tel-02483990⟩