Very Low Bit Rate Video Compression Based On Monitoring The Scene

The latest developments in the Wireless networking fealm make it possible to transmit monitoring video signals through the Wireless network. But the available bandwidth for the wireless video transmitting is still extremely limited,for example,the GPRS can only afford 9.6kbps for the video transmitting applications. So,great emphasis is put on the Very-Low-Bitrate (VLB) video compression techniques.Monitoring video signals have greater compression potential than the ordinary ones. But facing the challenge of the extremely limited bandwidth,new problems will emerge too. The low frame rate of the monitoring video also makes it possible to use more complex arithmetic to gain greater compression ratio.In this thesis,the appropriate techniques for the compression of the monitoring video,aiming at the bitrate lower than 10kbps (typically 9.6kpbs),is studied.We choose the H.263 compression standards. And according to the characteristics of the VLB compression of the monitoring video,we carry out some researches to improve the performance of H.263 encoder,mainly about the developing of the new bitrate control strategy for the VLB monitoring video coding.This thesis is organized as follow:in Chapter 1,we introduce the development history of monitoring system and its primary characteristics. In Chapter 2,a brief review of the VLB video compression techniques is presented. We carry out some experiments to test the practical performance of the advanced encode mode of the H.263 in Chapter 3. Chapter 4 is the main part of this thesis,in which we optimize the motion estimation and IDCT calculation of the H.263 encoder program,implement the early detection of all-zero DCT coefficients in it,and introduce a new bitrate control strategy to meet the new demands of the VLB monitoring video coding. In Chapter 5,we redesign the architecture and data flow of the encoder program according to the characteristics of DSP. At last,we summarize our researches in Chapter 6,and propose some advices to give directions to the following work..