Browsing by Author "Chin, HY"

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A bandwidth and memory efficient MPEG-4 shape encoder
(2004)
Lee, KB
;
Chang, NYC
;
Chin, HY
;
Hsu, HC
;
Jen, CW
We have developed a shape encoder hardware for MPEG-4 video coding. On the one hand, the alpha component is compressed and therefore, the size and memory access of alpha frame memory can be reduced to 50% and 56.25% respectively. On the other hand, an efficient data transfer scheme combining the run length coding and addressing mode can reduce average data transfer time to 9.39% and accelerate the shape encoding process. The shape encoder can support MPEG-4 Main Profile at Level 4 in real-time. In addition, verification and testing methods are also considered.
Optimal frame memory and data transfer scheme for MPEG-4 shape coding
(2004-02-01)
Lee, KB
;
Chin, HY
;
Chang, NYC
;
Hsu, HC
;
Jen, CW
An optimal frame memory and data transfer scheme is proposed for MPEG-4 shape coding in embedded systems. The proposed alpha frame buffer scheme contains two approaches. First, a distributed tile-based memory organization is used to efficiently support the time-varying size of alpha plane. Second, a compression scheme is used to reduce the number of memory access to and the size of the alpha frame memory. Under the criteria of MPEG-4 standard, the size of alpha frame memory can be reduced to 50% by introducing a small index table (2.73%-5.08% of the original frame memory size). A coarse assessment shows that the number of memory reference can be reduced to 56.25%. On the other hand, the proposed data transfer scheme combines the run length coding and addressing mode to reduce average data transfer time to 9.39%. Therefore, the shared system bus can be kept as free as possible, which in turn leads to increasing the potentialities of improvement on system performance. Furthermore, this data transfer scheme also helps in accelerating the processing of shape coding(1).
Optimal frame memory and data transfer scheme for MPEG-4 shape coding
(2003)
Lee, KB
;
Chang, NYC
;
Chin, HY
;
Hsu, HJ
;
Jen, CW
An optimal frame memory and data transfer scheme is proposed for MPEG-4 shape coding in embedded system. Based on the inherent property of shape information, the binary alpha blocks are losslessly compressed with a fixed 50% compression ratio and can be randomly accessed. Therefore the size of frame memory can be reduced to 50% with a small index table (2.73% similar to 5.08% of the original frame memory size), and the number of memory reference can be reduced to 56.25%. The data transfer scheme combines the run length coding and addressing mode to reduce data transfer time to 9.39%.
QME: An efficient subsampling-based block matching algorithm for motion estimation
(2004)
Lee, KB
;
Chin, HY
;
Hsu, HC
;
Jen, CW
;
電子工程學系及電子研究所
This paper presents a new pel subsampling-based search algorithm for motion estimation. The proposed quartet-pel motion estimation (QME) search algorithm reduces the number of pels taken into account for the cost function of the matching criteria at every search position, therefore reduces the computational complexity and the required memory bandwidth. Furthermore, the proposed algorithm has a regular data flow, which in turn leads to hardware-efficient implementations. Simulation results show that QME achieves almost the same coding performance as full-search block matching algorithm (FBMA) in terms of PSNR and the size of the coded bitstream. A flexible and efficient architecture design using QME is also proposed. The flexibility is based on the configurations of processing units, such that the processing time and memory access of QME architecture can be reduced with facility. On the other hand, the efficiency of proposed hardware design, characterized by normalized processing capability per gate, also surpasses other designs.