An Efficient Mode Decision Algorithm for H.264/AVC Encoding Optimization (original) (raw)

Mode decision optimization issues in H.264 video coding

Proceedings of the Fifth IEEE International Symposium on Signal Processing and Information Technology, 2005., 2005

The high compression efficiency ensured by the JVT H.264 video coding standard is mostly based on the adoption of a variable block-size motion estimation and mode decision. However, these advanced features imply a remarkable increase in the encoder complexity. To face the complexity issues, a number of algorithms and techniques have been developed, with the aim to speed up both the processes. In this paper, one of the algorithms proposed for Fast Mode Decision is reviewed and evaluated, with respect to the Reference Software implementation, and some improvements are suggested, in order to make its behavior adaptable to the video content.

An adaptive algorithm for fast inter mode decision in the H.264/AVC video coding standard

IEEE Transactions on Consumer Electronics, 2000

The H.264/AVC video coding standard achieves a high coding efficiency compared to previous standards. However, the encoder complexity results in a very high computational cost due to motion estimation and macroblock mode decisions. In this paper, we propose a simple, content adaptive mode decision method suitable for a variety of applications. Experimental results show that the proposed algorithm effectively reduces about 60% of the encoding time with negligible quality loss in respect to the reference model and it compares favorably with two of the most recognized algorithms in the literature 1 .

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.

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.

A Fast and Efficient Inter Mode Decision Algorithm for the H.264/AVC Video Coding Standard

2013

The H.264/AVC video coding standard is used in a wide range of applications from video conferencing to high-definition TV. Compared to the previous standard, the H.264/AVC has significantly better performance in terms of PSNR and visual quality at the same bit rate. It uses a complex mode decision technique based on rate-distortion optimization (RDO). Therefore, this technique introduces a high computational complexity. However, the computational complexity is one key challenge for the high efficient compression. In order to reduce the H.264/AVC complexity a new efficient and fast mode decision algorithm, based on the spatial homogeneity and temporal stationary characteristics of the current macroblock, is proposed in this paper. The experimental results show that the proposed algorithm is able to reduce up to 66,90 % of the computational complexity compared to the high complexity algorithm in the JM16.1 reference software with tolerant performance degradation.

An efficient Mode Selection Prior to the Actual Encoding for H.264/AVC Encoder

Many video compression algorithms require decisions to be made to select between different coding modes. In the case of H.264, this includes decisions about whether or not motion compensation is used, and the block size to be used for motion compensation. It has been proposed that constrained optimization techniques, such as the method of Lagrange multipliers, can be used to trade off between the quality of the compressed video and the bit rate generated. In this paper, we show that in many cases of practical interest, very similar results can be achieved with much simpler optimizations. Mode selection by simply minimizing the distortion with motion vectors and header information produces very similar performance to the full constrained optimization, while it reduces the mode selection and over all encoding time by 31% and 12%, respectively. The proposed approach can be applied together with fast motion search algorithms and the mode filtering algorithms for further speed up.

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.

Sequence Independent very Fast Mode Decision Algorithm on H.264/AVC Baseline Profile

2006

In this paper we propose a new fast mode decision (FMD) algorithm for H.264/AVC to reduce the computational load of the motion estimation (ME) process. It is oriented to dramatically reduce the encoding time regardless of the level of motion present at the sequences (high or lowmotion). The algorithm decides as the best mode the SKIP Mode or Mode 1 without need to compute the rest of coding alternatives if some conditions are satisfied. These conditions ensure these modes to be used appropriately for low motion and high motion sequences respectively to achieve an appropriate rate distortion (RD) cost based on the results of the previous encoded frames. Tests have shown reductions of the encoding time around -81% for all kinds of sequences, while moderate loss of coding efficiency.

Mode Decision-Based Algorithm for Complexity Control in H.264/AVC

IEEE Transactions on Multimedia, 2000

The latest H.264/AVC video coding standard achieves high compression rates in exchange for high computational complexity. Nowadays, however, many application scenarios require the encoder to meet some complexity constraints. This paper proposes a novel complexity control method that relies on a hypothesis testing that can handle time-variant content and target complexities. Specifically, it is based on a binary hypothesis testing that decides, on a macroblock basis, whether to use a low-or a high-complexity coding model. Gaussian statistics are assumed so that the probability density functions involved in the hypothesis testing can be easily adapted. The decision threshold is also adapted according to the deviation between the actual and the target complexities. The proposed method is implemented on the H.264/AVC reference software JM10.2 and compared with a state-of-theart method. Our experimental results prove that the proposed method achieves a better trade-off between complexity control and coding efficiency. Furthermore, it leads to a lower deviation from the target complexity.

Fast mode selection for H. 264 video coding standard based on motion region classification

2011

Abstract H. 264/AVC achieves higher compression efficiency than previous video coding standards. However, the process of selecting the optimal coding mode for each macroblock (MB) results in extremely high computation complexity, which make it difficult for practical use. In this paper, an efficient algorithm is proposed to reduce the complexity of MB mode selection. The proposed algorithm identified the interior region of the motion object by using the motion vectors information firstly.