A Fast and Lossless IDCT Design for AVS2 Codec
The emerging ultra-HD video content and the latest generation video coding standards such as HEVC and AVS2 involve significant computational complexity increase. Aiming to reduce the complexity of IDCT process, a fast IDCT design for AVS2 is presented in this paper, which bases on skipping the calculations of zero coefficients. After statistical analysis, we design several patterns for transform blocks with different sizes to detect the distribution of non-zero coefficients. If a transform block conforms to one of our designed patterns, the corresponding simplified IDCT function will be executed. Experimental results showed that our strategy could reduce the computation time by 19.3% on average under various test conditions. Moreover, our method will not result in any coding performance loss.