Fast intra-mode decision method based on DCT coefficients for H.264/AVC
This paper presents an efficient intra-mode decision method for H.264/AVC. By slightly changing the mode examination order, the proposed method obtains the discrete cosine transform (DCT) coefficients of the original \(4 \times 4\) image blocks without requiring any additional computation. These DCT coefficients are efficiently utilized to determine the best modes for \(4 \times 4\) luma blocks. Then, the proposed method makes use of the best mode information of the \(4 \times 4\) luma blocks to determine the best modes for \(16 \times 16\) luma blocks. A new chroma mode decision method is also presented, which efficiently combines several DCT coefficients from various \(4 \times 4\) sub-blocks. As a result, the proposed method reduces the encoding time of the conventional methods while also improving the coding performance significantly. Simulation results show that the average BD-BR of the proposed method is 1.63% while the reduction in the encoding time of the reference software is 66.3% on average.
dct coefficients h.264/avc mode decision intra-prediction