• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.250-256
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• 2014

Non-reference P frame coding is used to enhance coding efficiency in low-delay encoding configuration of Internet Video Coding (IVC), which is being standardized as a royalty-free video codec in MPEG. The existing method of non-reference P frame coding which was adopted in the reference Test Model of IVC (ITM) 4.0 adaptively applies a non-reference P frame with a fixed coding structure based on the magnitude of motion vectors (MVs), however, which unexpectedly degrades the coding efficiency for some sequences. In this paper, the existing non-reference P frame coding is improved by changing non-reference P frame coding structure and applying a new adaptive method using the ratio of the amount of generated bits of non-reference frames to that of reference frames as well as MVs. Experimental results show that the proposed non-reference P frame coding gives 6.6% BD-rate bit saving in average over ITM 7.0.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.298-300
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• 2004

In the decoding process of interframe wavelet coding, the inverse wavelet transform requires huge computational complexity. However, the decoder may need to be used in various devices such as PDAs, notebooks, PCs or set-top Boxes. Therefore, the decoder's complexity should be adapted to the processor's computational power. A decoder designed in accordance with the processor's computational power would provide optimal services for such devices. So, it is natural that the complexity scalability and the low complexity codec are also listed in the requirements for scalable video coding. In this contribution, we develop a method of controlling and lowering the complexity of the spatial wavelet transform while sustaining almost the same coding efficiency as the conventional spatial wavelet transform. In addition, the proposed method may alleviate the ringing effect for certain video data.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.5 no.1
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• pp.1-11
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• 2006

Lifting scheme based integer transforms provides very useful properties on the multimedia coding. An integer transform outputs the integer form when the input has integer value. This doesn't produce quantization errors on coding, so integer transforms are adequate to lossless coding, In this paper, we present an integer DCT algorithm which is able to transform audio signal with longer length. Also the proposed method can be easily implemented recursively even though input is long time. We present the method to overcome the poor approximation which is produced by recursive lifting step. And we have applied the proposed integer DCT to lossless audio coding.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.730-733
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• 2003

Dual coding technique is one of the popular techniques to reduce the dynamic false contours on PDP. Subfield pattern is a key factor affecting the performance of dual coding technique. In this paper, an optimum subfield selection method based on genetic algorithm is proposed. Two types of string structures are defined to account for all the possible configurations of the dual coding subfield patterns. Genetic operators are proposed for optimization of dual coding subfield pattern. Quantitative measures to describe degrees of dynamic false contours and checkerboard patterns are defined. Experimental results indicate that dual coding subfield pattern that is determined by proposed method reduces dynamic false contours and checkerboard patterns.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.79-82
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• 2008

We propose a new motion vector skip coding method for better motion compensation-based coding of inter-slices in H.264/AVC. It is to best utilize the spatial correlation between motion vectors of adjacent 4x4 blocks by effective motion vector coding. For this purpose, we introduce a new macroblock type of Predictive (P) slice into those of the H.264/AVC, so that it can lead to reduction in the coding bits required for encoding motion information. Experimental results with several well-known test video sequences verify that better performance of the proposed method is obtained.

• Journal of Industrial Technology
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• v.15
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• pp.93-101
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• 1995

Fractal coding is a promising method for image compression, but it has not lived up to its promise as low bit-rate image compression scheme. The existing algorithms for finding self-mapping contractive transforms are computationally expensive and offer a poor rate-quality tradeoff. In this paper, we propose a segment based fractal coding. We classify the range blocks into shade, midrange or edge blocks, and segment edge block along the edge. And we apply midrange coding scheme for each segment. Our experiments show that our method gives better rate-qualty trade of than current fractal block coding methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.726-742
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• 2000

A novel rte control algorithm consisting of two major components, i.e. a variable encoding frame rate method and a hybrid DCT/wavelet I-frame coding scheme, is proposed in this work for low bit rate video coding. Most existing rate control algorithms for low bit rate video focus on bit allocation at the macroblock level under a constant frame rate assumption. The proposed rate control algorithm is able to adjust the encoding frame rate at the expense of tolerable time-delay. Furthermore, an R-D optimized hybrid DCT/wavelet scheme is used for effective I-frame coding. The new rate-control algorithm attempts to achieve a good balance between spatial quality and temporal quality to enhance the overall human perceptual quality at low bit rates. It is demonstrated that the rate control algorithm achieves higher coding efficiency at low bit rates with a low additional computational cost. The variable frame rate method and hybrid I-frame coding scheme are compatible with the bi stream structure of H.263+.

• ETRI Journal
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• v.28 no.2
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• pp.145-154
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• 2006

In the decoding process associated with interframe wavelet coding, the inverse wavelet transform requires high computational complexity. However, as video technology starts to pervade all aspects of our lives, decoders are becoming required in various devices such as PDAs, notebooks, PCs, and set-top boxes. Therefore, a decoder's complexity needs to be adapted to the processor's computational power, and consequently a low-complexity codec is also required for scalable video coding. In this paper, we propose a method of controlling and lowering the complexity of the spatial wavelet transform while sustaining the same coding efficiency as that currently afforded. In addition, the proposed method may alleviate the ringing effect for slowly changing image sequences.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.579-582
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• 2001

Vector Transformation is a new method unified vector quantization and coding. So far, codebook generation applied to coding was LBG algorithm. But using the advantage of SOFM(Self-Organizing Feature Map) based on neural network can improve a system's performance. In this paper, we generated VTC(Vector Transformation Coding) codebook applied with SOFM algorithm and compare the result for several coding rates with LBG algorithm. The problem of Vector quantization is complicated calculation and codebook generation. So, to solve this problem, we used neural network approach method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1677-1685
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• 1988

In this paper, a new contour coding algorithm is investigated for use in region based image coding. Generally the contour data may be encoded by its chain codes or chain difference codes. But the data compression efficiency is low because of heavy burden for initial absolute coordinates of each chain. To alleviate this problem, the depth first search in graph traversal algorithm, is applied to the chain difference coding method. The proposed coding scheme is shown to be very efficient for contour images obtained by split-merge segmentation. Finally, we can reuce data about 60% in comparison with modified chain difference coding.