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结合空时OFDM和转换编码技术,提出了一种无线衰落信道下具有可分级转码能力的鲁棒视频传输方法.采用可分级转码器将高质量的MPEG2压缩视频转换为低码率、低分辨率MPEG4可分级码流来满足网络带宽和终端设备显示的要求.在接收端采用一种层干扰抑制算法,使得分层空时OFDM系统不同层的传输性能存在差异,从而使系统具有不对等保护能力.根据分级码流的重要程度不同,将转码输出的可分级码流分别由分层空时编码OFDM系统的不同层来实现视频的鲁棒传输.实验结果表明:在典型的随机突发错误的无线环境下,提出的具有可分级转码能力的系统的视频传输性能优于传统的非分级转码的视频传输系统.
Combining space-time OFDM and transcoding techniques, a robust video transmission method with scalable transcoding capability in wireless fading channels is proposed, using a scalable transcoder to convert high quality MPEG2 compressed video to low bit rate, low Resolution MPEG4 scalable code stream to meet the requirements of network bandwidth and terminal equipment display.A layer interference suppression algorithm is used at the receiving end to make the transmission performance of different layers of layered space-time OFDM system different, According to the importance of hierarchical streams, the scalable bitstreams of transcoded output are respectively transmitted by different layers of layered space-time coded OFDM system to achieve robust video transmission.Experimental results show that in typical randomized processes Under the wrong wireless environment, the proposed video transmission system with scalable transcoding capability outperforms the traditional non-hierarchical transcoding video transmission system.