• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.190-206
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• 2011

We propose an adaptive combination scheme of intra and inter prediction modes, where uni-directional intra prediction, bi-directional intra prediction, and inter prediction method are adaptively selected in an EMB (extended macro block). For each EMB, after all inter blocks have been encoded and decoded, the reconstructed blocks are used as reference data for bi-directional intra prediction of other blocks. Whereas conventional intra coding scheme does not use the right and below side pixels of the current block as reference data, the proposed method uses those for bi-directional intra prediction mode. In this paper, we propose three advanced techniques; (a) filter design for bi-directional prediction, (b) adaptive coding order scheme which increases the chance to use the bi-directional intra prediction mode, (c) modification of syntax to represent coding order. The information for the coding order is informed to the decoder by using the modified syntax structure without adding any additional flag. The simulation results show that the proposed scheme reduces the BD-Rate by 0.5%, on average, compared to KTA.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.91-94
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• 2003

H.264/AVC is the upcoming video coding standard of ITU-T H.264 and ISO MPEG-4 AVC. The new standard can achieve a significant improvement up to 50％ in compression ratio compared to MPEG-4 advanced simple profile. In this paper, we propose the novel intra prediction scheme to speed up intra prediction process in H.264/AVC decoder and show the hardware architecture for it. The proposed scheme uses the concurrent processing of the 4$\times$4 intra prediction, which is based on that some 4$\times$4 block pairs in a 16$\times$16 luma block can be processed concurrently. The proposed scheme can reduce intra prediction time by 33 ％.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.72-78
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• 2008

Although the H.264 video coding scheme is popular, it is not efficient for high-definition (HD) video coding because the size of its macroblock is relatively small for the HD video resolution. In this paper, we propose a new intra coding scheme based on the enlarged macroblock size. For the luminance component, intra $4{\times}4$ prediction and intra $16{\times}16$ prediction in H.264 are scaled into intra $8{\times}8$ prediction and intra $32{\times}32$ prediction, respectively. For the chrominance components, intra $8{\times}8$ prediction is extended to intra $16{\times}16$ prediction. Along with the $8{\times}8$ basic coding block size, an $8{\times}8$ integer discrete cosine transform (DCT) is used. Experimental results show that the proposed algorithm improves coding efficiency of the intra coding for HD video: PSNR gain by 0.23dB and bit-rate reduction by 5.32% on average.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.4
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• pp.235-241
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• 2016

Compared to the former H.264 standard, the number of the prediction modes has highly increased in HEVC intra prediction. Compression efficiency and accurate prediction are significantly improved. However, the computational complexity increases as well. To solve this problem, this paper proposes the new scheme where not only prediction modes but also block partition candidate are early chosen. Compared to the original intra prediction in HEVC, the proposed scheme achieves about 38% reduction in processing cycles with a marginal loss in compression efficiency.

• ETRI Journal
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• v.28 no.6
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• pp.721-731
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• 2006

A fast intra skip detection algorithm based on the ratedistortion (RD) cost for an inter frame (P-slices) is proposed for H.264/AVC video encoding. In the H.264/AVC coding standard, a robust rate-distortion optimization technique is used to select the best coding mode and reference frame for each macroblock (MB). There are three types of intra predictions according to profiles. These are $16{\times}16$ and $4{\times}4$ intra predictions for luminance and an $8{\times}8$ intra prediction for chroma. For the high profile, an $8{\times}8$ intra prediction has been added for luminance. The $4{\times}4$ prediction mode has 9 prediction directions with 4 directions for $16{\times}16$ and $8{\times}8$ luma, and $8{\times}8$ chrominance. In addition to the inter mode search procedure, an intra mode search causes a significant increase in the complexity and computational load for an inter frame. To reduce the computational load of the intra mode search at the inter frame, the RD costs of the neighborhood MBs for the current MB are used and we propose an adaptive thresholding scheme for the intra skip extraction. We verified the performance of the proposed scheme through comparative analysis of experimental results using joint model reference software. The overall encoding time was reduced up to 32% for the IPPP sequence type and 35% for the IBBPBBP sequence type.

• ETRI Journal
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• v.28 no.4
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• pp.425-434
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• 2006

We propose a fast macroblock mode prediction and decision algorithm based on contextual information for Pslices in the H.264/AVC video standard, in which the mode prediction part is composed of intra and inter modes. There are nine $4{\times}4$ and four $16{\times}16$ modes in the intra mode prediction, and seven block types exist for the best coding gain based on rate-distortion optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a fast inter mode prediction scheme is applied that uses contextual mode information for P-slices. We verify the performance of the proposed scheme through a comparative analysis of experimental results. The suggested mode search procedure increased more than 57% in speed compared to a full mode search and more than 20% compared to the other methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.170-173
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• 2009

In this paper, we propose a fast intra prediction mode selection method in Scalable Video Coding(SVC) which is an emerging video coding standard as an extension of H.264/Advanced Video Coding(H.264/AVC). The proposed method decides a candidate intra prediction mode based on the characteristic of macroblock smoothness. Statistical analysis is applied to computing that smoothness in spatial enhancement layer. We also propose an early termination scheme for Intra_BL mode decision where the RD cost value of Intra_BL is utilized. Compared with JSVM software, our scheme can reduce about 55% of the computation complexity of intra prediction on average, while the performance degradation is negligible; For low QP values, the average PSNR loss is very negligible, equivalently the bit rate increases by 0.01%. For high QP values, the average PSNR loss is less than 0.01dB, which equals to 0.25% increase in bitrate on average.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.255-258
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• 2006

In the H.264/AVC standard, intra prediction increases the coding efficiency of intra macroblocks and by applying rate-distortion optimization to each macroblock, it is possible to choose Inter or Intra encoding adaptively. This sort of encoding scheme, however, increases encoding complexity dramatically and causes troubles in practical applications of the real-time mobile environment. In order to decrease the complexity, variety of methods is proposed but most of those take only its current block into consideration for selecting candidate modes which naturally causes degradation in PSNR (Peak Signal to Noise Ratio). The proposed fast intra mode decision finds the candidate modes by analyzing transformed coefficients of neighboring blocks stored in the buffer at the encoder stage of input sequences. We verify this proposed scheme in complexity, PSNR and bit-rate.

• Journal of Broadcast Engineering
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• v.12 no.5
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• pp.491-502
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• 2007

In this parer, we propose an efficient intra prediction mode decision scheme in Scalable Video Coding(SVC) which is an emerging video coding standard as an extension of H.264/MPEG-4 AVC(Advanced Video Coding). The proposed method in base on the characteristic of macroblock smoothness follows the statistical analysis of intra prediction mode in an enhancement layer and it decides a candidate intra prediction mode. We also propose an early termination scheme for Intra_BL mode decision where the RD cost value of Intra_BL is utilized. Simulation results show that the proposed method reduces 54.67% of the computation complexity of intra prediction coding, while the degradation in video quality is negligible; for low QP values, the average PSNR loss is very negligible, equivalently the bit rate increases by 0.011%. For high QP values, the average PSNR loss is less than 0.01dB, which equals to 0.249% increase in bitrate.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.836-846
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• 2014

To expedite UHD (Ultra High Definition) video service, the HEVC (High-Efficiency Video Coding) technology has recently been standardized and it achieves two times higher compression efficiency than the conventional H.264/AVC. To obtain the improved efficiency, however, it employs many complex methods which need complicated calculation, thereby resulting in a significantly increased computational complexity when compared to that of H.264/AVC. For example, to improve the coding efficiency of intra frame coding, up to 35 intra prediction modes are defined in HEVC, but this results in an increased encoding time than the H.264/AVC. In this paper, we propose a fast intra prediction mode decision scheme which reduces computational complexity by changing the number of intra prediction mode in accordance with the percentage of PU sizes for a given video resolution, and by classifying the 35 intra prediction modes into 4 categories considering video resolution and quantization parameter. The experimental results show that the total encoding time is reduced by about 7% on average at the cost of only 2% increase in BD-rate.