基于模板匹配的调色板方法

Palette Improvement for Template Matching Intra Coding

使用模板匹配的方法对屏幕视频进行编码时,视频图像中近80%像素点残差为零.为了更好地对非零残差点进行编码,进一步提高编码效率,提出基于模板匹配的调色板方法.该方法利用非零残差点的统计信息,生成全局的和局部的调色板,使用调色板索引重新对非零残差点进行编码,进一步缩小预测残差.实验结果表明,采用文中方法对非零残差进行修正,最多可提升30%的编码效率.

With the development of wireless network and hand-hold devices such as i Pad, personal digital assistant and smartphone, screen content video becomes more popular for screen sharing or screen broadcasting. In our previous work, we proposed a pixel granularity template matching prediction method; almost 80% residual samples are zero for some screen content picture, and other 20% non-zero prediction residuals are encoded with the intuitive method. In order to further improve the coding efficiency, a palette based method is proposed in this paper. During encoding, a global palette and a local palette will be derived according to the statistics of non-zero residuals. Non-zero residuals will be encoded with the palette index. Palettes, indices and residuals will be transmitted. The experiment results show that the proposed palette tool can greatly improve the coding efficiency.