Fast Mode Decision for H.264 Based on DC Coefficient

The video coding standard H.264/AVC is adopted to multimedia communications due to its high compression efficiency. The high coding efficiency of H.264 is mainly acquired from the newly allowed prediction schemes including variable block mode. However these schemes require very high complexity to select the optimal mode. Direct-Current (DC) coefficient represents the main energy of the signal. In this paper, a fast mode decision algorithm, called the DC-based Fast Mode Decision (DC-FMD), has been presented to reduce the complexity of mode decision procedure for Predictive-Frame based on DC coefficient by reducing the number of modes required to be checked. Experimental results have shown that the proposed algorithm reduces the encoding time much by 36%-77% and greatly increases the average PSNR (peak signal-to-noise ratio) by 0.06dB-0.28dB while incurring up to 9.9% reduction or up to 4.53% increment on the total bit rate, especially that it greatly improves the video gain while reducing the total bit rate achieved by the exhaustive mode decision algorithm in some cases.