Browsing by Author "Chiang, TH"

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A complexity aware variable-bit-depth motion estimation
(2005)
Wang, SH
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Wang, CN
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Chiang, TH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Demands for using different complexity level algorithms to deliver multimedia content delivery over portable devices are increasing thanks to advanced battery technology. This paper describes a novel complexity aware motion estimation for H.264 based on pixel representation of different bit-depth and a simple scene change detection module. The experimental results show that with identical searching complexity, improvement on averaged PSNR is more than 0.2dB for 4-bit representation and more than 2 dB for 1/2-bit representation as compared to conventional bit-truncation method.
A fast audio bit allocation technique based on a linear R-D model
(2002-01-01)
Lee, CY
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Fang, YC
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Chuang, HC
;
Wang, CN
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Chiang, TH
This paper describes a fast bit allocation technique using a novel linear model for the bitrate and the global gain of the inner loop in the classic MP3 bit allocation. The outer loop is approximated with a binomial expansion. Our technique is five times faster compared to the LAME MP3 encoder.
A fast downsizing video transcoder based on H.264/AVC standard
(2004)
Li, CH
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Wang, CN
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Chiang, TH
;
交大名義發表
;
National Chiao Tung University
This paper presents a novel spatial transcoding technique for H.264/AVC based video applications. With superior coding performance, H.264 will be used in a variety of multimedia applications. For various video applications, spatial transcoding techniques can facilitate compact storage of video sequences with specified resolution and bitstrem format. Under demands, we can convert the archival bitstreams to another bitstream with different bitrates and different. resolution before transmission. For H.264 video transmission that needs spatial resolution conversion, we propose a bottom-up motion vector re-estimation, rapid rate-distortion (R-D) optimized mode decision. and adaptive motion search range to speed up the spatial transcoding and retain visual quality of transcoded video. The results show that the fast transcoder has the R-D performance close to or better than R-D re-encoding algorithm. which has the highest complexity and best coding efficiency.
A hierarchical decimation lattice based on N-queen with an application for motion estimation
(2003-08-01)
Wang, CN
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Yang, SW
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Liu, CM
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Chiang, TH
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資訊科學與工程研究所
We present a novel technique, N-queen lattice, to spatially subsample a block of pixels. Although this lattice is pertinent to many applications, we present an application to speed up motion estimation with minimal loss of coding efficiency. The N-queen lattice is constructed to characterize spatial features in all directions. It can be hierarchically organized for motion estimation With variable nonsquare block size. Despite the randomized lattice structure, we demonstrate that it is possible to achieve compact data storage architecture for efficient memory access and simple hardware implementation. Our simulations show that the N-queen lattice is superior to several existing sampling techniques with improvement in speed by about N times and small loss. in peak SNR.
A hierarchical N-queen decimation lattice and hardware architecture for motion estimation
(2004-04-01)
Wang, CN
;
Yang, SW
;
Liu, CM
;
Chiang, TH
;
資訊工程學系
A subsampling structure, an N-Queen lattice, for spatially decimating a block of pixels is presented. Despite its use for many applications, we demonstrate that the N-Queen lattice can be used to speed up motion estimation with nominal loss of coding efficiency. With a simple construction, the N-Queen lattice characterizes the spatial features in the vertical, horizontal, and diagonal directions for both texture and edge areas. Especially in the 4-Queen case, every skipped pixel has the minimal and equal distance of unity to the selected pixel. It can be hierarchically organized for variable nonsquare block-size motion estimation. Despite the randomized lattice, we design compact data storage architecture for efficient memory access and simple hardware implementation. Our simulations show that the N-Queen lattice is superior to several existing sampling techniques with improvement in speed by about N times and small loss in peak SNR (PSNR). The loss in PSNR is negligible for slow-motion video sequences and is less than 0.45 M at worst for high-motion estimation sequences.
A low complexity Picture-in-Picture transcoder for Video-on-Demand
(2005)
Li, CH
;
Wang, CN
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Chiang, TH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The paper presents a low complexity transcoding (LCT) approach with Picture-in-Picture (PIP) functionality based on H.264/AVC standard for Video-on-Demand (VOD) application. To address the high complexity of H.264 decoding and encoding tools, the novel and fast LCT approach composes a PIP frame in the transform domain based on an auxiliary bitstream. The auxiliary bitstream is generated along with the primary bitstream to provide the syntax elements including the transform coefficients and motion information for a rapid frame composition. To balance the transcoding speed and the Rate-Distortion (R-D) performance, the PIP transcoding with the auxiliary bitstream is applied to all inter-coded frames and the partially re-encoding transcoding, is used for the intracoded frames. By removing the high complexity g spatial interpolation, modules including motion compensation, in-the-loop deblocking filter and inverse spatial prediction from the transcoding process of all inter-coded frames, the LCT approach can significantly increase the transcoding throughput with very low memory requirement. Our experimental results show that the R-D performance of the LCT scheme is almost identical to that of the cascaded re-encoding approach, which can provide the theoretical best quality with highest complexity. In addition, the LCT approach that allows users to select the location and size of the foreground frame is applicable to the applications with interactive PIP service.
A low complexity prioritized bit-plane coding for SNR scalability in MPEG-21 scalable video coding
(2005)
Peng, WH
;
Chiang, TH
;
Hang, HM
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a low complexity prioritized bit-plane coding scheme to improve the rate-distortion performance of cyclical block coding in MPEG-21 scalable video coding. Specifically, we use a block priority assignment algorithm to firstly transmit the symbols and the blocks with potentially better rate-distortion performance. Different blocks are allowed to be coded unequally in a coding cycle. To avoid transmitting priority overhead, the encoder and the decoder refer to the same context to assign priority. Furthermore, to reduce the complexity, the priority assignment is done by a look-up-table and the coding of each block is controlled by a simple threshold comparison mechanism. Experimental results show that our prioritized bit-plane coding scheme can offer up to 0.5dB PSNR improvement over the cyclical block coding described in the joint scalable verification model (JSVM).
A novel all binary motion estimation (ABME)
(2002)
Luo, JH
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Wang, CN
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Chiang, TH
;
交大名義發表
;
National Chiao Tung University
We present a fast motion estimation algorithm using only binary representation, which is desirable for both embedded system software optimization and hardware implementation with parallel architectures. Our experimental results have showed that it provides excellent performance at both low and high bitrates. Because of its binary only representation, he proposed algorithm offers low computational complexity and low memory bandwidth consumption. For multimedia embedded system design, we further investigated specific implementation technique with an example of Intel x86 processors. Finally we show that binarization methods are closely coupled to the accuracy of binary motion estimation algorithms. The binarization and coding efficiencies can be improved using various filters and binarization methods.
A novel all-binary motion estimation (ABME) with optimized hardware architectures
(2002-08-01)
Luo, JH
;
Wang, CN
;
Chiang, TH
;
資訊科學與工程研究所
;
電子工程學系及電子研究所
We present a fast motion estimation algorithm using only binary representation, which is desirable for both embedded system and hardware implementation with parallel architectures. The key algorithm distinction is that only the high-frequency spectrum is used. Our experimental results show that it provides excellent performance at both low and high bit rates. Because of its binary-only representation, the proposed algorithm offers low computational complexity and low memory bandwidth consumption. For multimedia-embedded system design, we further investigated specific implementation techniques for several well-known hardware platforms including Intel x86 processors, single-instruction multiple-data processors, and systolic array circuit design. The systolic array architecture requires only single memory access for both the reference and current frames from the on-chip memory. Such an implementation provides an optimized solution with great throughput, while the quality is maintained. Finally, we show that our binarization methods are closely coupled to the accuracy of binary motion estimation algorithms. The binarization and coding efficiencies can be improved using various filters and binarization methods.
A platform-based de-blocking filter design with bus-interleaved architecture for H.264
(2005)
Chang, SC
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Peng, WH
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Wang, SH
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Chiang, TH
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交大名義發表
In this paper, we present an ARM platform-based architecture design for de-blocking filter in H.264. According to statistical analysis, we propose an adaptive transmission scheme to reduce the bus workload. Moreover, we develop a bus-interleaved architecture to reduce the processing latency. As compared to the state-of-the-art designs, our scheme offers 3x to 14x performance improvement. Furthermore, we have proved our design using an ARM emulation board.
A platform-based MPEG-4 Advanced Video Coding (AVC) decoder with block level pipelining
(2003)
Wang, SH
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Peng, WH
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He, YW
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Lin, GY
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Lin, CY
We present a baseline MPEG-4 AVC (Advanced Video Coding) decoder based on an optimized platform-based design methodology. With this methodology, we jointly optimize the software and hardware design of the decoder. Overall decoding throughput is increased by synchronizing the software and the dedicated co-processors. The synchronization is achieved at macroblock-level pipelining. In addition, we optimize the decoder software by enhancing the frame buffer management, boundary padding, and content aware inverse transform. To speed up motion compensation and inverse transform, which are the most computationally intensive modules, two dedicated acceleration modules are realized. For comparison, the proposed prototype decoder and MPEG-4 AVC reference decoder are evaluated on an ARM platform, which is one of most popular portable devices. Our experiments show that the throughput of the MPEG-4 reference decoder can be improved by 6 to 7 times. On an ARM966 board, the optimized software without hardware acceleration can achieve a decoding rate up to 5 frames per second (fps) for QCIF video sequences. With the dedicated accelerators, the overall throughput is increased by about 30% to reach 6.6 fps on the average and is up to 10.3 fps for slow motion video sequences.
A prioritized end-to-end video streaming scheme using MPEG-4 fine granularity scalability
(2002)
Peng, WH
;
Chiang, TH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a new client buffer management scheme to adaptively regulate and optimize the decoded video quality for video streaming applications. Our scheme packetizes and prioritizes the video bitstream of MPEG-4 Fine Granularity Scalability. We assign individual packet a priority factor according to its rate-distortion performance and the buffer is managed based on the received aggregate priority factor for each frame. Since the packetization process considers the priority, our algorithm can use such information to perform real-time packets/bits allocation at the client buffer. For a given available bandwidth and constrained processing power, we provide improved performance in terms of reduction of visual quality variation and enhancement of overall visual quality.
A robust fine granularity scalability using trellis-based predictive leak
(2002-06-01)
Huang, HC
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Wang, CN
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Chiang, TH
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資訊科學與工程研究所
;
電子工程學系及電子研究所
Recently, the MPEG-4 committee has approved the MPEG-4 fine granularity scalability (FGS) profile as a streaming video tool. In this paper, we propose novel techniques to further improve the temporal prediction at the enhancement layer so that coding efficiency is superior to the existing FGS. Our approach utilizes two parameters, the number of bitplanes beta (0 less than or equal to beta less than or equal to maximal number of bitplanes) and the amount of predictive leak alpha (0 less than or equal to alpha less than or equal to 1), to control the construction of the reference frame at the enhancement layer. These parameters alpha and beta can be selected for each frame to provide tradeoffs between coding efficiency and error drift. Our approach offers a general and flexible framework that allows further optimization. It also includes several well-known motion-compensated FGS techniques as special cases with particular sets of alpha and beta. We analyze the theoretical advantages when parameters alpha and beta are used, and provide an adaptive technique to select alpha and beta, which yields an improved performance as compared to that of fixed parameters. An identical technique is applied to the base layer for further improvement. Our experimental results show over 4 dB improvements in coding efficiency using the MPEG-4 testing conditions. The removal of error propagation is demonstrated with several typical channel transmission scenarios.
A robust MPEG-21 media delivery video streaming system
(2004)
Su, TL
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Huang, MY
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Chuang, HC
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Wang, CN
;
Chiang, TH
MPEG-21 provides a unified solution, Universal Multimedia Access (UMA), for constructing a multimedia content delivery and rights management framework. Based on the concepts of UMA, we build a simplified UMA model for Internet and over wireless LAN. In this framework, the source video material is encoded and archived as MPEG-4 bitstreams. Moreover, novel intra refresh and error resilience schemes are used to improve the coding efficiency and robustness of the delivered bitstreams. Consequently, the multimedia information can be streamed through the transmission channels with packet losses. The recovered images have insignificant quality degradations for similar streaming systems. To have a more strict evaluation methodology according to the specified common conditions for MPEG-21 media delivery, a unicast streaming system is built on MPEG-21 part-13 Multimedia Test Bed for Resource Delivery. The results show that we can retain significantly improved subjective quality for video streaming over the Internet and wireless channels.
A study of monomer's effect on adhesion strength of UV-curable resins
(2006-10-01)
Chiang, TH
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Hsieh, TE
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材料科學與工程學系
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Department of Materials Science and Engineering
This work studies the effects of the monomer types, the number of hydroxyl functional groups (-OH) on polyol monomers, and the equivalent weight ratio of dicycloaliphatic epoxide to polyol for cationic polymerization (the R value) on the adhesion strength of UV-curable epoxy resins applied to organic light-emitting device (OLED) packaging. It was found that the volume shrinkage of resins after UV curing is related to the crosslinking density of the resin. The smallest volume shrinkage implied the highest adhesion strength of resin on glass substrate since the internal stress was minimized. This study observed that the resin containing polyol monomer is able to achieve the smallest degree of shrinkage (1.72%) and the highest adhesion strength (153.35 kg/cm(2)) on glass substrate. (C) 2005 Elsevier Ltd. All rights reserved.
A VBR rate control using MINMAX criterion for video streaming
(2002)
Li, CH
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Wang, CN
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Chiang, TH
;
資訊工程學系
;
電子工程學系及電子研究所
In this paper, we present a frame-level rate control scheme based on a modified linear Rate-Distortion model to achieve minimal maximum (MINMAX) distortion for frame-dependent quantizers. The MINMAX distortion measure is used because the worst visual quality often dominates the overall perceptual quality. In our approach, we first perform the iterative offline analysis of the rate-distortion behavior for the original sequences on a video server. Such compactly stored information enables the encoder to select quantization parameters in real-time during streaming process. Our results show that our algorithm obtains higher minimum PSNR values than the TM5 rate control while the average PSNR is similar. We also use the same technique to optimize statistical multiplexing for a multi-channel transmission application.
Advances of MPEG scalable video coding standard
(2005)
Peng, WH
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Tsai, CY
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Chiang, TH
;
Hang, HM
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交大名義發表
To support clients with diverse capabilities, the MPEG committee is defining a novel scalable video coding (SVC) framework that can simultaneously support multiple spatial, temporal and SNR resolutions under the constraints of low complexity and low delay. To fulfill the requirements, two major approaches have been considered as the potential technologies. One is the wavelet-based scheme and the other is the scalable extension of MPEG-4 AVC/H.264. This paper aims to give a brief overview for the latest advances of these technologies.
Context-based binary arithmetic coding for fine granuality scalability
(2003)
Peng, WH
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Chiang, TH
;
Hang, HM
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We proposed a context-based binary arithmetic coding to improve entropy coding of the enhancement layer for the H.26L-, based Fine Granularity Scalability (FGS). Instead of independent bit-plane coding, we exploit correlation between various bit-planes and neighboring coefficients. For each bit-plane, we perform significant/refinement bit partition and construct contexts separately in terms of energy clustering and distribution of DCT coefficients. For the significant bit, we extend one-dimensional run-length coding to multiple dimensions and segment the significant bit-planes. For the refinement bit, we put together refinement bits exhibiting stronger correlation by energy groups and apply run-length coding distinctively. Particularly, we introduce the maximum run concept to offer better statistical adaptation. Averagely, our approach reduces the enhancement-layer bit stream by 7similar to8% and improves the PSNR by 0.3similar to0.5dB. Moreover, our performance outperforms the JPEG-2000 for the encoding of the enhancement layer.
Context-based binary arithmetic coding with stochastic bit reshuffling for advanced Fine Granuality Scalability
(2004)
Peng, WH
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Wang, CN
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Chiang, TH
;
Hang, HM
;
交大名義發表
We present a novel context based binary arithmetic coding with a stochastic bit-reshuffling scheme to improve bit-plane coding of MPEG-4 Fine Granularity Scalability (FGS). Current approach has not fully considered the correlations across bit-planes and among adjacent transform blocks. To fully exploit correlation, we construct context based on spatial correlation and energy distribution of transform blocks. Furthermore, we consider the context across bit-planes to reduce side information. In addition. when the enhancement-layer is partially decoded, the block update in a raster scan causes unbalanced quality of a decoded frame. To have consistent subjective quality, we reshuffle the bit transmission order with a probability model. Since both encoder and decoder have identical probability model, no extra overhead are required. For faster convergence of statistic adaptation.. we replace the traditional 8 x 8 floating point DCT with 4 x 4 integer transform. As compared to MPEG-4 FGS based bit-plane coding, we can improve the PSNR by 0.5similar to1dB and offer better subjective quality. Specifically, our approach is among top 3 of the Test 1(b) and 1(c) in the subjective quality evaluation of scalable video coding in the 65th MPEG meeting in July 2003.
Efficient FGS to single layer transcoding
(2002)
Lin, YC
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Wang, CN
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Chiang, TH
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Vetro, A
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Sun, HF
This paper presents novel architecture for the transcoding of FGS coded video to a single-layer format. Results indicate that the proposed architecture has almost the same performance as the cascaded transcoding method, but with much lower complexity.