Research On Video-Sharing System In The Digital Home Network Based On Scalable Video Coding Technology

The video stream becames the main information flow in the digital home network with the development of digital home. However, there are different needs of video service between different users in the digital home network, there are different needs of video resolution and video quality between different video client devices and there are different calculating abilities between different video client devices. In addition, the digital home network with inherent heterogeneity, unreliability and bandwidth fluctuation is not conducive to video transmission.The video-sharing system in the digital home network based on scalable video coding technology, which is research in this paper, is good to adapt to the diversity of needs of video service, the diversity of video client devices and bandwidth fluctuations of network. This video-sharing system encodes the video and generate multiple layers of video streams by using scalable video coding technology. One layer of video streams, with lower bit rate, is called the base layer video stream, which can be decoded separately, other layers of video streams are called the enhancement layer video stream, which can be decoded with the base layer video stream for better video quality. This video-sharing system achieves spatial scalability by using a scalable video coding method for resolution based on DCT, achieves SNR scalability by using a stepwise quantization method and measures the available bandwith of network real-timely by using a passive available bandwidth measurement method according to the characteristics of video transmission.The passive available bandwidth measurement method is improved in this paper. The video server and the video client on the edge of the network are used in this method. The video client measures the datasize of a group of pictures of video transmission, measures the time for transporting this group of pictures and then estimates the average available bandwidth in this period. This video-sharing system makes the video quality match the available bandwith of network adaptively by using a scalable video transmission method based on video trace, which is improved in this paper. This scalable video transmission method based on video trace includes producting the video trace file, making the data of video stream match the available bandwith of network and organizing the video stream. When the available bandwith of network is low, the bit rate of transported video stream is low and the video quality is not high, however, when the available bandwith of network becomes higher, the bit rate of transported video stream also becomes higher and the video quality becomes higher too.The results show that this video-sharing system makes video be shared well in the digital home network, adapts to the difference of needs of video service, the difference of video client devices and bandwidth fluctuations of network and has good performance.