As far as we know, cloud computing is a new business model and the cloud computing architecture is the famous topic recently. Today, everyone enjoy the innovative search engine or social network application for new Internet services no longer require the large capital outlays in hardware to access those service or the human expense to operate it. Currently, Google is the largest search engine and Face book is the largest social network in the Software as a Service (SaaS). But how them can support the huge requests from world thought each personal computer, mobile device, and smart phone. In this paper, we will try to analysis their backend cloud computing architecture to support future SaaS especially in large social network.

A low complexity fast mode decision algorithm for H.264/AVC intra prediction that uses discrete cross differences (DCD) to reduce the unlikely candidate modes in the RDO calculation is proposed. By using horizontal and vertical differences in different locations, the directions of the edges can be precisely detected. Experimental results show that the proposed fast mode decision algorithm reduces the encoding time by about 56%, with negligible loss of video quality. To realize the proposed algorithm, a VLSI design, which is comprised of a cross difference unit and direction detection unit, is implemented for the mode pre-selection stage of intra prediction. The design is synthesized using UMC 0.18 mum CMOS technology and simulated with Verilog-XL. The operating frequency of the synthesized core can exceed 50 MHz.