The paper reports a new fast intra prediction algorithms based on separating the transformed coefficients of neighboring blocks. The prediction blocks are obtained from the transformed and quantized neighboring blocks that generate minimum distortion for each DC and AC coefficients. To obtain fast coding with comparable coding efficiency compared to H.264/AVC, we present the full block search prediction (FBSP) and the edge based distance prediction (EBDP). These are immune to both the intra prediction error and the drift propagation; in addition, do not require a low pass filtering named extrapolation and mode decisions to obtain a prediction block. In FBSP, eight neighbor blocks (B(i-j)) are chosen to be candidates by observing the edge direction of the current block ((0,0)), where (i,j) are relative displacement position to the current block denoted as (i,j) G {(0,-1), (-1, 0), (-1, -1), (+1, -1), (-2, -1), (-1, -2), (+2, -1), (+1, -2)}, and the prediction block can be obtained by combining DC and AC coefficients of a neighboring block generating minimum distortion of residues. In EBSP, the edge directions of the current block are estimated from DCT coefficients, and intuitionally the prediction block is selected by observing the minimum edge distance (difference) compared to the current block without any distortion measurements. We have applied the proposed algorithms to MPEG test sequences which are Foreman, Hall, Mother and Daughter and Mobile. A PSNR (peak signal to noise ratio) gain of -2 to +0.8dB is observed at various bit rates shown in Figure l(a)(b), where + indicates PSNR degradation, - denotes PSNR gain compared to H.264/AVC intra coding. In case of a complex scene in terms of edges, the prediction error could be more dominant rather than one caused by quantization, the proposed method shows the same or better coding efficiency due to its insensitivity of the prediction error and the drift propagation. Analyzing of computational complexity, the proposed algorithms require less than 15% complexity compared to low complexity mode of H.264/AVC in Figure 1(c) since they does not perform an extrapolation and mode decisions which generates intensive computational complexity in H.264/AVC intra coding.

Solid-state lighting is a rapidly growing area of research and applications, due to the reliability and predicted high efficiency of these devices. The white LED sources that are typically used for general illumination can also be used for data transmission, and Visible Light Communications (VLC) is a rapidly growing area of research. One of the key challenges is the limited modulation bandwidth of sources, typically several MHz. However, as a room or coverage space would typically be illuminated by an array of LEDs there is the potential for parallel data transmission, and using optical MIMO techniques is potentially attractive for achieving high data rates. In this paper we investigate non-imaging and imaging MIMO approaches: a non-imaging optical MIMO system does not perform properly at all receiver positions due to symmetry, but an imaging based system can operate under all foreseeable circumstances. Simulations show such systems can operate at several hundred Mbit/s, and up to Gbit/s in many circumstances.

An efficient multi-hypothesis error concealment algorithm for H.264 video is proposed in this work. The proposed algorithm temporally conceals a lost block by combining several hypothesis blocks in the previous frame. We investigate the error recovery performance according to the number of hypotheses and the weighting coefficients. Simulation results demonstrate that the proposed algorithm provides better performance than the conventional error concealment algorithm, although the additional complexity requirement is negligible.

The rate control is important to allocate bits efficiently for getting better performance, such as high quality, low fluctuation of quality and low mismatch between a target bit rate and an encoded bit rate. In this paper, we present an improved frame-layer H.264/AVC rate control scheme using enhanced complexity measure, scene-change detection, and quantization parameter adjustment for low bit rate video. Especially, our complexity measure contains not only the residual information but also the motion information. We use the motion vector difference encoded previously as motion information for low computation-load encoder. Experimental results show that Y-PSNR and bit-rate mismatch are remarkably improved and the fluctuation of Y-PSNR is similar as compared with the conventional H.264/AVC rate control scheme (JVT-G012)