• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.114-124
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• 2014

HEVC is a state-of-the-art video coding standard developed by JCT-VC. HEVC provides about 2 times higher subjective coding efficiency than H.264/AVC. One of the main goal of HEVC development is to efficiently coding UHD resolution video so that HEVC is expected to be widely used for coding UHD resolution video. Decoding such high resolution video generates a large number of memory accesses, so a decoding system needs high-bandwidth for memory system and/or internal communication architecture. In order to determine such requirements, this paper presents an analysis of the memory access complexity for HEVC decoder. we first estimate the amount of memory access performed by software HEVC decoder on an embedded system and a desktop computer. Then, we present the memory bandwidth models for HEVC decoder by analyzing the data flow of HEVC decoding tools. Experimental results show the software decoder produce 6.9-40.5 GB/s of DRAM accesses. also, the analysis reveals the hardware decoder requires 2.4 GB/s of DRAM bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1019-1024
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• 2005

MPEG-2 achieves high compression radio, by exploiting the temporal and spatial correlations in real image sequence, using the motion compensated prediction and the transform coding, respectively. However, as the image sequence is more highly compressed, the encoded bitstream becomes more vulnerable to transmission error over the noisy channels. Furthermore, er개rs in the headers are fatal to decoding processes, because the header parameters in the video coding standard include a lot of important information connected to the syntax elements, fables, and decoding process. In this paper, we propose a new error resilience method using LSB coding for header parameters in MPEG-2 coded video transmissions. The experimental results for football and susie video sequence demonstrate that the proposed error resilience method for header parameters in MPEG-2 bitstream has good performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.79-89
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• 2011

Recent development of embedded processors makes it possible to play back video contents in real-time on portable devices. Because of their limited battery capacity and low computational performance, however, portable devices still have significant problems in real-time decoding of high quality or high resolution compressed video. Although previous approaches are successful in achieving complexity-scalable decoder by controlling computational complexity of decoding elements, they cause significant objective quality loss coming from mismatch between encoder and decoder. In this paper, we propose a selective B slice skip-decoding method to implement a low complexity video decoder. The proposed method performs selective skip decoding process of B slice which satisfies the proposed conditions. The skipped slices are reconstructed by simple reconstruction method utilizing adjacent reconstructed pictures. Experimental result shows that proposed method not only reduces computational complexity but also maintains subjective visual quality.

• Journal of Multimedia Information System
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• v.4 no.1
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• pp.19-26
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• 2017

The compression of video for both full HD and UHD requires the inclusion of extra vertical lines to every video frame, named as the DTV essential hidden area (DEHA), for the effective functioning of the MPEG-2/4/H encoder, stream, and decoder. However, while the encoding/decoding process is dependent on the DEHA, the DEHA is conventionally viewed as a redundancy in terms of channel utilization or storage efficiency. This paper proposes a block mode DEHA method to more effectively utilize the DEHA. Partitioning video block images and then evenly filling the representative DEHA macroblocks with the average DC coefficient of the active video macroblock can minimize the amount of DEHA data entering the compressed video stream. Theoretically, this process results in smaller DEHA data entering the video stream. Experimental testing of the proposed block mode DEHA method revealed a slight improvement in the quality of the active video. Outside of this technological improvement to video quality, the attractiveness of the proposed DEHA method is also heightened by the ease that it can be implemented with existing video encoders.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.62-67
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• 2001

In the recent mobile communication systems, the performance of Turbo Code using the error correction coding depends on the interleaver influencing the free distance determination and the recursive decoding algorithms that is executed in the turbo decoder. However, performance depends on the interleaver depth that need a large time delay over the reception process. Moreover, Turbo Code has been known as the robust ending method with the confidence over the fading channel. The International Telecommunication Union(ITU) has recently adopted as the standardization of the channel coding over the third generation mobile communications such as IMT-2000. Therefore, in this paper, we proposed of the method to improve the conventional performance with the parallel concatenated 4-New Turbo Decoder using MAP a1gorithm in spite of complexity increasement. In the real-time video and video service over the third generation mobile communications, the performance of the proposed method was analyzed by the reduced decoding delay using the variable decoding method by computer simulation over AWGN and fading channels.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.151-161
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• 2009

Audio Video Standard (AVS) is the audio and video compression standard that was developed for domestic video applications in China. AVS employs low complexity tools to minimize degradation of RD performance of the state-the-art video codec, H.264/AVC. The AVS video codec consists of $8{\times}8$ block prediction and the same size transform to improve compression efficiency for VGA and higher resolution sequences. Currently, the AVS has been adopted more and more for IPTV services and mobile applications in China. So, many consumer electronics companies and multimedia-related laboratories have been developing applications and chips for the AVS. In this paper, we implemented the AVS video decoder and optimize it on TI's Davinci EVM DSP board. For improving the decoding speed and clocks, we removed unnecessary memory operations and we also used high-speed VLD algorithm, linear assembly, intrinsic functions and so forth. Test results show that decoding speed of the optimized decoder is $5{\sim}7$ times faster than that of the reference software (RM 5.2J).

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.745-754
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• 2005

This paper proposes an information hiding algorithm using channel coding technique which can be used to detect transmission errors and to protect copyright for MPEG-2 video The watermark signal is generated by applying copyright information of video data to a convolutional encoder, and the signal is embedded into macro blocks in every frame while encoding to MPEG-2 video stream In the decoder, the embedded signal is detected from macro blocks in every frame, and the detected signal is used to localize transmission errors in the video stream. The detected signal can also be used to claim ownership of the video data by decoding it to the copyright Information. In this stage, errors in the detected watermark signal can be corrected by channel decoder. The 3 video sequences which consist of 300 frames each are applied to the proposed MPEG-2 codec. Experimental results show that the proposed method can detect transmission errors in the video stream while decoding and it can also reconstruct copyright information more correctly than the conventional method.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.61-64
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• 1999

The turbo code appropriate to IMT-2000 is known to have a good performance whenever the size of frame increases. But it is not appropriate to a sort of video service to need real time because of decoding complexity and long delay time by the size of frame. Therefore this paper proposes decoding decision algorithm of short frame in which soft output is weighted according to iteration number in turbo decoder. Performance of the proposed algorithm is analysed in the AWGN channel when short length of frame is 100, 256, 640. As the result. it is appeared that the proposed decoding decision algorithm has improved in BER other than in the existing MAP decoding algorithm.

• Journal of Multimedia Information System
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• v.4 no.4
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• pp.179-188
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• 2017

The Internet Video Coding (IVC) standard is due to be published by Moving Picture Experts Group (MPEG) for various Internet applications such as internet broadcast streaming. IVC aims at three things fundamentally: 1) forming IVC patents under a free of charge license, 2) reaching comparable compression performance to AVC/H.264 constrained Baseline Profile (cBP), and 3) maintaining computational complexity for feasible implementation of real-time encoding and decoding. MPEG experts have worked diligently on the intellectual property rights issues for IVC, and they reported that IVC already achieved the second goal (compression performance) and even showed comparable performance to even AVC/H.264 High Profile (HP). For the complexity issue, however, there has not been thorough analysis on IVC decoder. In this paper, we analyze the IVC decoder in view of the time complexity by evaluating running time. Through the experimental results, IVC is 3.6 times and 3.1 times more complex than AVC/H.264 cBP under constrained set (CS) 1 and CS2, respectively. Compared to AVC/H.264 HP, IVC is 2.8 times and 2.9 times slower in decoding time under CS1 and CS2, respectively. The most critical tool to be improved for lightweight IVC decoder is motion compensation process containing a resolution-adaptive interpolation filtering process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.107-108
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• 2012

For low complexity encoder, the parity bit transmission through a feedback channel is an essential part of DVC. But feedback channel-based parity bit control is a major cause for the high decoding time latency. In this paper, we propose a fast distributed video decoding by parity bit request estimation using rate-distortion model. Through computer simulations, it is shown that the proposed method can achieve complexity reduction compared to other methods.