A Line-based Intra Coding Scheme

A new line-based intra coding scheme is presented to improve the coding efficiency. Unlike conventional block-based video coding, the spatial multi-prediction is performed in the line-based manner in horizontal or vertical direction, which improves the prediction accuracy by shortening the distance between the reference and current pixels; then, One Dimensional Discrete Cosine Transform (1DDCT) is directly applied to compact the one dimensional residuals; at last, the scanning order is adjusted to fit for the block-based entropy coding process. The line-based modes together with the three modes used in H. 264/AVC are selected at the level of macroblocks by minimizing the rate distortion cost. Experimental results show that, compared with the H. 264/AVC, the proposed framework reduces the bit rate by approximately 4% and up to 6% for both CIF and 720P sequences at the same PSNR.