An efficient low bit-rate video-coding algorithm focusing on moving regions

Abstract

Abstract-Block-based motion estimation and compensation are the most popular techniques for video coding. However, as the shape and the structure of an object in a picture are arbitrary, the performance of such conventional block-based methods may not be satisfactory. In this paper, a very low bit-rate video coding algorithm that focuses on moving regions is proposed. The aim is to improve the coding performance, which gives better subjective and objective quality than that of the conventional coding methods at the same bit rate. Eight patterns are pre-defined to approximate the moving regions in a macroblock. The patterns are then used for motion estimation and compensation to reduce the prediction errors. Furthermore, in order to increase the compression performance, the residual errors of a macroblock are rearranged into a block with no significant increase of high-order DCT coefficients. As a result, both the prediction efficiency and the compression efficiency are improved.

Video coding using arbitrarily shaped block partitions in globally optimal perspective

“…We have assumed that if the number of '1's in a CRMB is too low or too high, the corresponding MB is not suitable to be encoded by the pattern mode, and thus, we do not include these CRMBs in the pattern generation process that is to be described next. In the proposed technique, if the number of '1's is less than 8 (same as in [13]), the MB has very low movement so that it can be encoded as skipped block. On the other hand, if the total number of '1's is more than 64 + 2QP/3, the MB has very high motion so that it can be encoded using standard H.264 modes.…”

“…The moving region M of a MB Ω in the current frame is obtained using the co-located MB ω in the reference frame [13] as follows:…”

“…Pattern-based video coding (PVC) initially proposed by Wong et al [13] and later extended by Paul et al [14,15] used 8 and 32 pre-defined regular-shaped binary rectangular and non-rectangular pattern templates respectively to segment the moving region in a MB to exploit the ITR. Note that a pattern template is a size of 16 × 16 positions (i.e., similar to a MB size) with 64 '1's and 192 '0's.…”