A subband/DCT based fast mode decision algorithm for H.264

In this paper, we propose a fast mode decision algorithm for intra and inter prediction for H.264/AVC video coding. Here the subband decomposition of the input video is done for the fast mode prediction. To the LL band of the subband decomposition of the video, exhaustive intra prediction is done. To the LH, HL and HH bands selective intra prediction modes are used for the intra prediction. For the inter mode decision, the motion estimation is performed for the LL band and the motion vectors obtained are used directly for the high frequency bands. The proposed method reduces the computational complexity and time considerably while maintaining similar PSNR and bit rate. Experimental results for various test sequences at different resolutions are presented to show the effectiveness of the proposed method.