• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.227-238
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• 2000

This paper, at first, provides analysis on loss pattern of Internet based on real experiments of the current Internet. Then, we propose an effective adaptive QoS management technique, in which measured loss pattern as well as PLR (Packet Loss Ratio) are used to select titrate of temporal scalability. level of FEC and retransmission This selection is also incorporated to the MPEG-4 error resilience tools and error concealment techniques. In order to minimize effect of packet loss, multimedia stream is segmented in the unit of group of Pictures (GOP) and interleaving and FEC are applied to the segment. Proposed algorithms are applied to build a VOD system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.4
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• pp.315-324
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• 2005

VOD(video on demand) is a video service by users' order, that is, a video service on demand. That means the users can select and watch the video content that has been saved on sewer, out of broadcasting in the usual process like TV. At present the client of VOD system bases on PC. As the PC-based client uses the software MPEG decoder, the main processor specification has an effect on the capacity. Also people, who don't know how to use their PC, cannot be provided the VOD service. The purpose of this paper is to show the process of the development the VOD client system Into the embedded type with hardware MPEG-4 decoder. The main processor is the SC1200 of x86 Family in National Semiconductor with a built-in video processor and the memory is 128Mbyte SDRAM. Also, in order that the VOD service can be provided using the Internet, the Ethernet controller is included. As the hardware MPEG-4 decoder is used in the embedded VOD client system, which is developed, it can make the low capacity of the main processor. Therefore it is able to be developed as a low-price system. The embedded VOD client system is easy for anyone to control easily with the remote control and can be played through TV.

• ETRI Journal
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• v.35 no.4
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• pp.655-665
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• 2013

Hybrid digital multimedia broadcasting (DMB) is a next-generation mobile TV system that combines broadcasting and wireless communication networks and can provide various high-quality multimedia services. However, if a system adheres to the current standard of transmitting the DMB content in the form of MPEG2-TS through wireless networks, it results in a burden on the network due to low transmission efficiency. The reasons for the low transmission efficiency are as follows. First, due to its constant bitrate characteristic, DMB MPEG2-TS includes a considerable amount of needless information, such as NULL packets and stuffing bytes. Second, due to the inflexibility of the Real-time Transport Protocol (RTP) standard, one cannot fully utilize the maximum transmission unit of the network when converting MPEG2-TS to RTP stream for transmission. This paper proposes a new transmission scheme that resolves these problems. Experiment results show that the proposed scheme improves data bitrate transmission efficiency by 8% to 36%, compared to the standard scheme, in the streaming of various real-DMB contents.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.1 s.307
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• pp.27-34
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• 2006

In this paper, we propose a combined region-based image retrieval system using EHD(Edge Histogram Descriptor) and CLD(Color Layout Descriptor) of MPEG-7 descriptors. The combined descriptor can efficiently describe edge and color features in terms of sub-image regions. That is, the basic unit for the selection of the region-of-interest (ROI) in the image is the sub-image block of the EHD, which corresponds to 16 (i.e., $4{\times}4)$ non-overlapping image blocks in the image space. This implies that, to have a one-to-one region correspondence between ELE and CLD, we need to take an $8{\times}8$ inverse DCT (IDCT) for the CLD. Experimental results show that the proposed retrieval scheme can be used for image retrieval with the ROI based image retrieval for MPEG-7 indexed images.

• Journal of Broadcast Engineering
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• v.11 no.3 s.32
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• pp.263-275
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• 2006

This paper introduces an interactive contents authoring system which can easily and conveniently produce interactive contents for the Terrestrial Digital Multimedia Broadcasting (T-DMB). For interactive broadcasting service, T-DMB adopted MPEG-4 BIFS technology. In order to the interactive service becomes flourishing on the market, various types of interactive contents should be well provided prior to the service. In MPEG-4 BIFS, broadcasting contents are described by the combination of a large number of nodes, routes and descriptors. In order to provide interactive data services through the T-DMB network, it is essential to have an interactive contents authoring system which allows contents authors to compose interactive contents easily and conveniently even if they lack any background on MPEG-4 BIFS technology. The introduced authoring system provides powerful graphical user Interface and produces interactive broadcasting contents in the forms of binary and textual format. Therefore, the BIFS contents authoring system presented in this paper would vastly contribute to the flourishing interactive service.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.11
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• pp.57-62
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• 2011

In this paper, an efficient architecture for MFVLD(Multi-Format Variable Length Decoder) which can process H.264, MPEG-2, MPEG-4, AVS, VC-1 bitstream is proposed. The proposed MF-VLD is designed to be adapted to the MPSOC (Multi-processor System on Chip) architecture, uses bit-plane algorithm for the processing of inverse quantized data to reduce the width of AHB bus. External SDRAM is used to minimize the internal memory size. In this architecture, the adding or removing each variable length decoder can be easily done by using multiplexor. The designed MF-VLD can be operated in 200MHz at 0.18um process. The gate size is 657K gate and internal memory size is 27Kbyte.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11
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• pp.3509-3518
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• 2000

Due to a recent advance on the internet access technologies such as ADSL and ISDN, ti becomes possible to watch movies or listen to music at home through the internet. In this paper, we propose Implementation technique and expenence we lcarnet in the development of media plavers operating on Q+ reall-time operating system. The media player can manipulate MPS, MPEG-1, and MPEG-4 streams, and the decofing routime is implemented by software. Ths medial player is operated on the digital TV set-top-box and is implomented by using Q+ librares. In this paper, we focus on programming technique on q+ real-time operating system and performance enhancement technique.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.43-48
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• 2000

This paper introduces MPEG-2 AAC codec system fur digital audio broadcasting. This system consists of encoder and decoder, and this system provides MPEG-2 system multiplexing and demultiplexing functions. Four DSPs are adopted fur encoder and three DSPs fur decoder. Each DSP processes system control, I/O control, and audio signal processing, multiplexing and demultiplexing. This paper also discusses about some near future estimations related to DAB system and services. And at the end of this paper describes about future development plans.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.138-148
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• 2001

Digital Video (DV) coding standards for digital video cassette recorder are based mainly on DCT and variable length coding. DV has low hardware complexity but high compressed bit rate of about 26 Mb/s. Thus, it is necessary to encode video with low complex video coding at the studios and then transcode compressed video into MPEG-2 for video-on-demand system. Because these coding methods exploit DCT, transcoding in the DCT domain can reduce computational complexity by excluding duplicated procedures. In transcoding DV into MPEC-2 intra coding, multiplying matrix by transformed data is used for 4:1:1-to-4:2:2 chroma format conversion and the conversion from 2-4-8 to 8-8 DCT mode, and therefore enables parallel processing. Variance of sub block for MPEG-2 rate control is computed completely in the DCT domain. These are verified through experiments. We estimate motion hierarchically using DCT coefficients for transcoding into MPEG-2 inter coding. First, we estimate motion of a macro block (MB) only with 4 DC values of 4 sub blocks and then estimate motion with 16-point MB using IDCT of 2$\times$2 low frequencies in each sub block, and finish estimation at a sub pixel as the fifth step. ME with overlapped search range shows better PSNR performance than ME without overlapping.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.37-42
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• 2006

This paper proposes a adaptive video watermarking algorithm according to bitrate and motion vector size in MPEG2 system. The watermark strength in the I-frames is adapted for quantization step size and the strength in the P-B-frames is adapted for quantization step size and motion vector of macroblock to make the watermark more robust against the accompanying degradation due to aggressively compression. A realtime watermark extraction is done directly in the DCT domain during MPEG decoding without full decoding of MPEG video. The experimental simulations show that the video quality results almost invisible difference between the watermarked frames and the original frames and the watermark is resistant to frame dropping, MPEG compression, GoP conversion and low pass filter attacks.