This paper proposes an efficient zero-block inter mode decision algorithm for high bit-rate coding in H.264/AVC, to improve computation efficiency of the previous algorithm [1]. In the proposed algorithm we suggest using zero-blocks of both 8×8 and 4×4 DCT coefficients to describe video sequences in detail, including global and local stationary characteristics. The experimental results reveal that significant computation improvement (up to 20% reduction) for high bit-rate coding can be achieved over the previous algorithm.

The popular video coding standard H.264/AVC features many advanced techniques in motion estimation, such as multiple reference frames, variable block sizes, and quarter pixel resolution. These new features significantly improve coding performance, but with extremely high computational complexity. To improve computation efficiency, this paper suggests a selective multiple reference frame motion estimation (SMRFME), which characterizes MRFME as a stationary Gaussian random process, and uses the stationary property to check whether a mode or a block is necessary to perform motion estimation on next reference frames. Experimental results reveal that the proposed SMRFME algorithm momentously improves computational complexity with an average reduction of 68% in total encoding time, and with negligible degradation in PSNR and bit-rate increment. The current research also compares SMRFME algorithm performance with the AFMFSA algorithm. Results demonstrate that the proposed algorithm outperforms the distinct algorithm in all aspects.

In this letter, a rate estimation technique using transform coefficient variance is proposed in the rate-distortion cost function for intra mode decision. The new cost function achieves better coding performance than the cost function using the ¿-domain model. The new cost function brings out an average speed-up factor of 13 when compared with the rate-distortion optimization (RDO) mode decision, but with considerable degradation in rate-distortion performance. To improve the coding performance, we propose a sum of the absolute transformed differences (SATD)-based mode decision algorithm, which incorporates both SATD and the variance information into the RDO mode decision method. The results show that the SATD-based mode decision scheme can achieve a significant improvement in computation (with 21% of total encoding time, or a speed-up factor of 5) with negligible peak signal-to-noise ratio loss. The proposed algorithm is also compared with two other distinct algorithms , and the results indicate that the proposed algorithm outperforms these two edge detection algorithms in coding performance, as well as time saving.

This letter proposes an enhanced sum of absolute transform differences (SATD)-based intra mode decision for H.264/advanced video coding intra frame coding, which is accomplished in two stages. In the first stage, the low-frequency AC components of discrete cosine transform block of a MB is used to select I4 MB or I16 MB mode prediction; while in the second stage SATD coefficients, including SATD value and its variance, is used to skip improper modes for rate-distortion optimization mode decision. This letter compares the proposed algorithm performance with other distinct algorithms such as image structure tensor and dominant edge direction, and so on, and the results indicate that the proposed algorithm significantly outperforms these algorithms, in both rate-distortion performance and computation performance.

In the previous work we presented a SATD-based intra mode decision algorithm for H.264/AVC to reduce the computational complexity, based upon SATD coefficients. In this paper, we extend the previous work and propose an improved SATD-based intra mode decision, which uses low-frequency components to provide local characteristics for intra mode selection. The experimental results reveal that our proposed algorithm can achieve significant reduction of computation time compared to the reference program, while still maintaining good coding performance. The proposed algorithm is also compared with two distinct algorithms and the results indicate that the proposed algorithm brings out higher reduction in computation that these two algorithms.

In the previous paper , we proposed a zero-block intermode decision algorithm for H.264 video coding based upon the number of zero-blocks of 4 x 4 DCT coefficients between the current macroblock and the co-located macroblock. The proposed algorithm can achieve significant improvement in computation, but the computation performance is limited for high bit-rate coding. To improve computation efficiency, in this paper, we suggest an enhanced zero-block decision algorithm, which uses an early zero-block detection method to compute the number of zero-blocks instead of direct DCT and quantization (DCT/Q) calculation and incorporates two adequate decision methods into semi-stationary and nonstationary regions of a video sequence. In addition, the zero-block decision algorithm is also applied to the intramode prediction in the P frame. The enhanced zero-block decision algorithm brings out a reduction of average 27% of total encoding time compared to the zero-block decision algorithm.

In the previous work, we presented a zero-block mode decision algorithm for H.264/AVC to reduce the computation time, based upon the number of zero blocks of 4times4 DCT coefficients between the current macroblock (MB) and the collocated macroblock. In this paper we extend the previous work and provide a more sophisticated algorithm, which uses an early zero-block detection method instead of DCT/Q computation, and incorporates adequate decision methods into semi-stationary and non-stationary regions of a video sequence. The simulation results demonstrate that the proposed algorithm can achieve up to 20% of time saving on average compared to the original zero-block mode decision algorithm, while maintaining a high coding performance.