Browsing by Author "Chang, NYC"

Now showing 1 - 5 of 5

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.
Architecture design of MPEG-4 texture decoder - Supporting object-based video coding
(2005)
Hsu, HC
;
Chang, NYC
;
Chang, TS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Handling of the complexity which arises due the irregularity data nature for MPEG-4 object based video coding is an important issue in MPEG-4 texture decoder design. Another crucial issue is designing an efficient architecture to satisfy the resource sensitive nature of portable embedded video codec systems. This paper presents an architecture for texture decoding to address these two major issues. By adopting zero-skipping and zero index tables together, the throughput and power consumption are improved significantly. To avoid incurring extra hardware overhead, multiplication sharing and buffer sharing are also incorporated. ne synthesized design can perform texture decoding of CIF@30FPS under 2.18 MHz. using UMC 0.181 mu m 1P6M technology, the reported power consumption is 0.92 mW.
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%.
Trace-path analysis and performance estimation for multimedia application in embedded system
(2004)
Chang, NYC
;
Lee, KB
;
Jen, CW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
High-level performance estimation can help assess the performance in the early development stage of embedded system with real-time constraint efficiently; however the estimation accuracy has long been an issue. In this paper, a performance estimation method called trace-path analysis based on high-level execution path tracing analysis which takes the effect of multiple execution paths into consideration is proposed. Multiple execution path resolutions and a linear model for non-deterministic node cost are incorporated to yield better estimation accuracy. The estimation of error is also covered in this context so that the degree of the estimation accuracy can be known. Experiments taking MPEG-4 shape coding as an example shows that the proposed approach can achieve an average of 1.88% estimation error per QCIF frame, which is better than the 12.38% of the bitstream analysis approach.