• Journal of KIISE:Software and Applications
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• v.27 no.8
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• pp.864-876
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• 2000

This paper proposes a new scene boundary detection scheme for the MPEG System stream using MPEG Audio information and proves its usefulness by extensive experiments. A scene boundary has a characteristic that the audio as well as video information are changed rapidly. This paper first classifies this scene boundary into three cases ; Radical, Gradual, Micro Changes, with respect to the audio changes. The Radical change has a large-scale changing of decibel value and pitch value at a scene boundary, the Gradual change shows the long-time transition of decibel and pitch values from max to min or vice versa, and the Micro change displays a some change of pitch or frequency distribution without decibel changes. Upon this analysis, a new scene change detection algorithm detecting these three cases is proposed in which a progressive window with a time line is used to trace the changes in the audio information. Some experiments with various movies show that proposed algorithm could produce a high detection ratio for Radical change that is the most popular scene change in the movies, while producing a moderate detection ratio for Gradual and Micro changes. The proposed scene boundary detection scheme could be used to build a database for visual information like MPEG System stream.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.665-671
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• 2020

MPEG-I is actively working on standardization on the coding of immersive video which provides up to 6 degree of freedom (6DoF) in terms of viewpoint. 3DoF+ video, which provides motion parallax to omnidirectional view of 360 video, renders a view at any desired viewpoint using multiple view videos acquisitioned in a limited 3D space covered with upper body motion at a fixed position. The MPEG-I visual group is developing a test model called TMIV (Test Model for Immersive Video) in the process of development of the standard for 3DoF+ video coding. In the TMIV, the redundancy between a set of input view videos is removed, and several atlases are generated by packing patches including the remaining texture and depth regions into frames as compact as possible, and coded. This paper presents an atlas generation method that removes small-sized blocks in the atlas for more efficient 3DoF+ video coding. The proposed method shows a performance improvement of BD-rate bit savings of 0.7% and 1.4%, respectively, in natural and graphic sequences compared to TMIV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.247-254
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• 2008

H.264 provides a good coding efficiency compared with existing video coding standards, H.263, MPEG-4, based on the use of multiple reference frame for variable block size motion estimation, quarter-pixel motion estimation and compensation, $4{\times}4$ integer DCT, rate-distortion optimization, and etc. However, many modules used to increase its performance also require H.264 to have increased complexity so that fast algorithms are to be implemented as practical approach. In this paper, among many approaches, fast mode decision algorithm by skipping variable block size motion estimation and spatial-predictive coding, which occupies most encoder complexity, is proposed. This approach takes advantages of temporal and spatial properties of fast mode selection techniques. Experimental results demonstrate that the proposed approach can save encoding time up to 65% compared with the H.264 standard while maintaining the visual perspectives.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.551-560
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• 2009

This paper proposes a method for efficient lossless depth map coding for MPEG 3D-Video coding. In general, the conventional video coding method such as H.264 has been used for depth map coding. However, the conventional video coding methods do not consider the image characteristics of the depth map. Therefore, as a lossless depth map coding method, this paper proposes a bit-plane based lossless depth mar coding method by using the MPEG-4 Part 2 shape coding scheme. Simulation results show that the proposed method achieves the compression ratios of 28.91:1. In intra-only coding, proposed method reduces the bitrate by 24.84% in comparison with the JPEG-LS scheme, by 39.35% in comparison with the JPEG-2000 scheme, by 30.30% in comparison with the H.264(CAVLC mode) scheme, and by 16.65% in comparison with the H.264(CABAC mode) scheme. In addition, in intra and inter coding the proposed method reduces the bitrate by 36.22% in comparison with the H.264(CAVLC mode) scheme, and by 23.71% in comparison with the 0.264(CABAC mode) scheme.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.77-78
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• 2008

With advent of 3G mobile communication services, video telephony becomes one of the major services. However, due to a narrow channel bandwidth, the current video telephony services have not yet reached a satisfied level. In this paper, we propose an ROI (Region-Of-Interest) based improvement of visual quality for video telephony services with the H.264|MPEG-4 Part 10 (AVC: Advanced Video Coding) codec. To this end, we propose a face detection and tracking method to define ROI for the AVC codec based video telephony. Experiment results show that our proposed ROI based method allowed for improved visual quality in both objective and subjective perspectives.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.465-472
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• 2003

In this paper we propose the structure of MPEG-4 multimedia player platform for Terrestrial Digital Multimedia Broadcasting (DMB) Service. Korea will launch DMB service at next 2004 you based on Eureka-147 Digital Audio Broadcasting (DAB) Service System. This new mobile multimedia broadcasting services provide not only high quality digital audio broadcasting services, but also various multimedia data broadcasting services including high quality video. For the sake of MPEG-4 Systems technologies, it will provide an interactive service to users in the near future. Therefore it terminal shall have various functionalities as well as playing audio-visual contents. However there is no precedence standard for such mobile interactive multimedia broadcasting system. Therefore it is very import to provide the multimedia player platform of DMB service for accelerating the development process of commercial terminal and providing a direction of next DMB terminal structure.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.32-43
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• 2010

This paper presents deblocking filter for low-complexity video decoder. Baseline profile of the H.264/AVC used for mobile devices such as mobile phones has two times higher compression performance than the MPEG-4 Visual but it has a problem of serious complexity as using 1/4-pel interpolation filter, adaptive entropy model and deblocking filter. This paper presents low-complexity deblocking filter for decreasing complexity of decoder with preserving the coding efficiency of the H.264/AVC. In this paper, the proposed low-complexity deblocking filter decreased 49% of branch instruction than conventional approach as calculating value of BS by using the CBP. In addition, a range of filtering of strong filter applied in intra macroblock boundaries was limited to two pixels. According to the experimental results, the proposed low-complexity deblocking filter decreased -0.02% of the BDBitrate comparison with baseline profile of the H.264/AVC, decreased 42% of the complexity of deblocking filter, and decreased 8.96% of the complexity of decoder.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.289-292
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• 2002

This paper provides a frame-layer method for controlling bit rate of compressed video data in real time. Our approach is easy to operate and can store encoded video data in real time without deteriorating the quality of an image. To provide ameliorated and consistent visual quality, a new concept named SOP (Set Of Pictures) and a new quantization parameter variation control algorithm based on a second-order rate-distortion model 〔2〕 are introduced. The total bit-budget is allocated efficiently to cope with unpredictable recording time by using the proposed algorithm and it is distributed to each frame. In the end, we show improved and consistent video quality with experimental results obtained from C-model of a MPEG-4 (simple-profile) encoder.

• Proceedings of the IEEK Conference
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• 2000.11d
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• pp.101-104
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• 2000

An efficient bit rate distribution technique that distributes available bits for multiple objects based on motion vector magnitude, size of object shape, and coding distortion is presented. This coding concept using the three parameters was exploited in MPEG-4 multiple object coding. But the scheme is likely to produce poor results such as allocating more bits to less important objects and degrading picture quality, due to the lack of analysis and research in view of human visual aspect. In this paper importance of each object is represented by the three parameters and visually analyzed. Target bits are distributed according to coding distortion using the pre-assigned shape and motion information.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.41-50
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• 2004

Since the MPEG-4 visual standard enables content-based functionalities, it is necessary to extract video objects from video sequences. Segmentation algorithms can largely be classified into two different categories: automatic segmentation and user-assisted segmentation. In this paper, we propose a new user-assisted image segmentation method based on the active contour. If we define a shape space as a set of all possible variations from the initial curve and we assume that the shape space is linear, it can be decomposed into the column space and the left null space of the shape matrix. In the proposed method, the shape space vector in the column space describes changes from the initial curve to the imaginary feature curve, and a dynamic graph search algorithm describes the detailed shape of the object in the left null space. Since we employ the shape matrix and the SUSAN operator to outline object boundaries, the proposed algorithm can ignore unwanted feature points generated by low-level image processing operations and is, therefore, applicable to images of complex background. We can also compensate for limitations of the shape matrix with a dynamic graph search algorithm.