A New Low-Complexity Integer Distortion Estimation Method for H.264/AVC Encoder

In this paper, a new low-complexity distortion estimation method for the H.264 rate-distortion optimized mode decision is proposed. Coding processes, such as discrete cosine transform (DCT), quantization, inverse quantization, inverse DCT, and reconstruction, are needed to compute the distortion in an H.264 encoder. To reduce these computations, we estimate the distortion using coefficients calculated in the quantization process and eliminate the inverse quantization, inverse DCT, and reconstruction processes. In the proposed method, the distortion is computed by integer operations, which is more efficient for the hardware implementation. The simulation results show that the proposed method can reduce the encoding time by about 10% with negligible degradation in the coding performance.