Fast mode decision algorithm for H.264/AVC using edge characteristics of residue images (original) (raw)

Improved inter mode decision for H.264/AVC using weighted prediction

2011

H.264/AVC video coding standard outperforms former standards in terms of coding efficiency but at the expense of higher computation complexity. Of all the encoding elements in H.264, inter prediction is computationally most intensive and thus adds to the computational burden for the encoder. In this paper, we propose a fast inter prediction algorithm for JVT video coding standard H.264/ AVC. Prior to performing the motion estimation for inter prediction, characteristics like stationarity and homogeneity of each macroblock is determined. The macroblocks correlation with neighboring macroblocks in respect of predicted motion vectors and encoding modes are studied. Weights are assigned for these parameters and the final mode is selected based upon these weights. The average video encoding time reduction in the proposed method is 70% compared to the JVT benchmark JM12.4 while maintaining similar PSNR and bit rate. Experimental results for various test sequences at different resolutions ...

Fast Mode Decision for Intra Prediction in H.264/AVC Encoder

2007

The H.264/AVC video coding standard uses the rate distortion optimization (RDO) method to improve the compression performance in the intra prediction. Whereas the computational complexity is increased comparing with previous standards due to this method, even though this standard selects the best coding mode for the current macroblock. In this paper, a fast intra mode decision algorithm for H.264/AVC encoder based on dominant edge direction (DED) is proposed. The algorithm uses the approximation of discrete cosine transform (DCT) coefficient formula. By detecting the DED before intra prediction, 3 modes instead of 9 modes are chosen for RDO calculation to decide the best mode in the 4x4 luma block. For the 16x16 luma and the 8x8 chroma, instead of 4 modes, only 2 modes are chosen. Experimental results show that the computation time of the proposed algorithm is decreased to about 71% of the full search method in the reference code with negligible quality loss.

A Fast Mode Decision Method for H.264/AVC Using the Spatial-Temporal Prediction Scheme

2006

In the H.264/AVC coding standard, seven motion estimation modes from 4 × 4 to 16 × 16 are used to find the minimum motion compensation error for each macroblock. However, the high computation cost of the full search method in the reference software JM-9.3 makes the encoding process inefficient. Therefore, the methods of applying the SAD (sum of absolute difference), homogeneous region analysis, and edge detection are developed to determine the optimum motion estimation mode. Nevertheless, the additional computation cost of image processing still reduces the efficiency of the motion compensation process. In this paper, the spatial-temporal correlations between the current frame and reference frame are analyzed to develop a fast mode decision method in which no extra image processes are used. Furthermore, the concept of drift compensation is adopted to avoid the error accumulation phenomenon during the mode decision process. The experimental results show that the computation cost may be reduced above 60% and the average PSNR is only dropped about 0.04db.

Fast intra mode decision algorithm for H.264/AVC video coding

2004

The emerging H.264-AVC video coding standard aims to significantly improve compression performance compared to all existing video coding standards. In order to achieve this, a robust rate-distortion optimization (RDO) technique is employed to select the best coding mode and reference frame for each macroblock. As a result, the complexity and computation load increase drastically. This paper presents a fast mode decision algorithm for H.264 intra prediction based on local edge information. Prior to intra prediction, an edge map is created and a local edge direction histogram is then established for each sub-block. Based on the distribution of the edge direction histogram, only a small part of intra prediction modes are chosen for RDO calculation. Experimental results show that the last intra mode decision scheme increases the speed of intra coding significantly with negligible loss of PSNR.

Fast mode-decision for H.264/AVC based on inter-frame correlations

Signal Processing: Image Communication, 2009

The H.264/AVC standard yields higher coding efficiency rates than other video coding standards. This is because it uses the rate-distortion optimization (RDO) technique, which selects the optimal coding mode and a reference frame for each macroblock (MB). In order to achieve this, the encoder has to encode a given block by exhaustively using all kinds of combinations (including different intra and inter-prediction modes). As a result, the computational complexity of video coding in H.264/AVC is extremely high. In this paper, two fast intra-/inter-mode-decision algorithms are proposed to reduce the complexity of the encoder. Both of these algorithms are based on the inter-frame correlation among adjacent pictures. For the fast intra-mode-decision, we used the intra-mode of the mostcorrelated MB at the reference frame to encode the current MB and the stationary property of the current MB was used for the fast inter-mode-decision. The simulation results show that the proposed algorithms significantly reduced the computational complexity with a negligible loss of PSNR and a slight increase in bitrate.

Fast mode decision algorithm for intraprediction in H.264/AVC video coding

IEEE Transactions on Circuits and Systems for Video Technology, 2005

The H.264/AVC video coding standard aims to enable significantly improved compression performance compared to all existing video coding standards. In order to achieve this, a robust rate-distortion optimization (RDO) technique is employed to select the best coding mode and reference frame for each macroblock. As a result, the complexity and computation load increase drastically. This paper presents a fast mode decision algorithm for H.264/AVC intraprediction based on local edge information. Prior to intraprediction, an edge map is created and a local edge direction histogram is then established for each subblock. Based on the distribution of the edge direction histogram, only a small part of intraprediction modes are chosen for RDO calculation. Experimental results show that the fast intraprediction mode decision scheme increases the speed of intracoding significantly with negligible loss of peak signal-to-noise ratio.

Dominant edge direction based fast intra mode decision in the H.264/AVC encoder

Journal of Zhejiang University SCIENCE A, 2009

The H.264/AVC video coding standard uses an intra prediction mode with 4×4 and 16×16 blocks for luma and 8×8 blocks for chroma. This standard uses the rate distortion optimization (RDO) method to determine the best coding mode based on the compression performance and video quality. This method offers a large improvement in coding efficiency compared to other compression standards, but the computational complexity is greater due to the various intra prediction modes. This paper proposes a fast intra mode decision algorithm for real-time encoding of H.264/AVC based on the dominant edge direction (DED). The DED is extracted using pixel value summation and subtraction in the horizontal and vertical directions. By using the DED, three modes instead of nine are chosen for RDO calculation to decide on the best mode in the 4×4 luma block. For the 16×16 luma and the 8×8 chroma, only two modes are chosen instead of four. Experimental results show that the entire encoding time saving of the proposed algorithm is about 67% compared to the full intra search method with negligible loss of quality.

An Efficient Intra Mode Selection Algorithm For H.264 Based On Fast Edge Classification

2007

The H.264/AVC is the newest video coding standard recommended by ITU-T and MPEG. Compared with all existing video coding standards, H.264 can achieve superior performance by using many advanced techniques. Intra mode selection is an important feature in H.264 standard and can reduce the spatial redundancy in intra-frame significantly. An efficient rate distortion optimization (RDO) technique is employed in H.264 to choose the best mode for each MB, but the computational cost increases drastically. In this paper, a fast intra-mode selection algorithm is introduced. By using a fast edge detection method which is based on non-normalized Haar transform (NHT), edge for each sub-block can be extracted. Based on the local edge information, only few intra-modes are chosen as mode candidates. A fast RDO algorithm is also proposed in this paper which is based on accurate rate-distortion estimation model and the fast intra-mode RDO method. By combining these two methods, computational load is reduced remarkably. Experimental results show that this fast intra-mode selection scheme can lessen the encoding time significantly with little loss of bit-rate and visual quality.

Fast Bit Rate Estimation for Mode Decision of H.264/AVC

IEEE Transactions on Circuits and Systems for Video Technology, 2000

To achieve the highest coding efficiency, H.264/AVC uses rate-distortion optimization technique. This means that the encoder has to code the video by exhaustively trying all the mode combinations including the different intra-and inter-prediction modes. Therefore, the complexity and computation load of video coding in H.264/AVC increase drastically compared to any previous standards. To reduce the complexity of rate-distortion cost computation, we propose a fast bit rate estimation technique to avoid the entropy coding method during intra-and inter-mode decision of H.264/AVC. The estimation method is based on the properties of context-based variable length coding (CAVLC). The proposed rate model predicts the rate of a 4 4 quantized residual block using five different tokens of CAVLC. Experimental results demonstrate that the proposed estimation method reduces about 47% of total encoding time on using intra-modes only and saves about 34% of total encoding time on using both inter-and intramodes with ignorable degradation of coding performance when the fast motion search algorithm is used. When full search motion estimation algorithm is used, the proposed algorithm reduces about 17% of total encoding time.

An Efficient Mode Decision Algorithm for H.264/AVC Encoding Optimization

IEEE Transactions on Multimedia, 2000

The H.264 video coding standard significantly outperforms previous standards in terms of coding efficiency. However, this comes as a cost of extremely high computational complexity due to mode decision where variable block size Motion Estimation (ME) is employed. In this paper, we propose an efficient algorithm to jointly optimize mode decision and ME. A theoretical analysis is performed to study the sufficient condition to detect all-zero blocks in H.264, and thus adaptive thresholds are derived to early terminate mode decision and ME. Besides the aforementioned early termination technique, the proposed algorithm also introduces temporal-spatial checking, thresholds based prediction and monotonic error surface based prediction methods to skip checking unnecessary modes. Experimental results demonstrate that the proposed algorithm can significantly reduce the computational complexity of H.264 encoding while maintaining almost the same Rate Distortion (RD) performance as the original encoder.