A Screen Sharing Scheme Based on Copying Screen and Data Compression
YU Zhan-wu · 2003
In multimedia application systems , recently emerging the need of compressing and transmiting a special video in Internet, which has the characters of full screen, half motion and non-continuous tone, for example, the content of PowerPoint files. In order to satisfied this need, this paper proposed an efficient scheme to acheive the high compressed ratio at the same time protecting the nearly lossless visual quality. This scheme is named sharing and includes the two main techniques, one is called copy-screen, and the other is the data-compression method called LZ77. The first step of this scheme is to copy the full and high resolution screen contents and save them as bitmap formats. The second step is to reduce the color resolution of these bitmap images, transforming the 24bit color definition into 4 or 8 bit color definition so that we can reduced the quantity of image data. The last step is to apply the lossless method to compress the low color resolution images. As to the non-continuous tone color images, the compressed ratio can reach up to 100:1, and it has real time performance, moreover, the decode process is fairly simple. So it can be easily used in network multimedia applications such as Distance Education and Remote Stock Comment Analysis System.