【摘要】 结合空时正交频分复用(OFDM)和转换编码技术,提出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.该方法可将高质量的MPEG-2压缩视频转换为低码率、低分辨率H.264可分级码流,以满足网络带宽和终端设备显示的要求.同时,考虑分级码流的重要性,转码输出的可分级码流经过分层空时编码的OFDM系统实现不对等保护传输.实验结果表明:在典型的随机突发错误的无线环境下,本文可分级转码能力的视频传输系统性能优于非分级转码的视频传输系统.更多还原

【Abstract】 This paper proposed a novel scheme for robust video transmission in dispersive fading channels.A scalable MPEG-2 to H.264 transcoder is used to output H.264 FGS bitstream with reduced size of video frames.With the proposed system,the concurrent large diversity gain characteristic of space-time block codes(STBC) and alleviating the frequency-selective fading effect of OFDM can be achieved.The different bitstreams are given in different level protection by the system structure and channel coding according to the important level of scalable bitstream.The simulation results indicate that the proposed scheme integrating scalable transcoding can provide a basic quality of video transmission and outperforms the convention single layer transcoding transmitted under the random and bursty error channel conditions.更多还原