Hsiu-Cheng Chang

A novel low-cost high-performance VLSI architecture for MPEG-4 AVC/H.264 CAVLC decoding

The demand of high quality video and high data compression enables MPEG-4 AVC/H.264 to adopt the context-based adaptive variable length code (CAVLC) technique contrary to the traditional MPEG-4 VLC techniques. The paper presents a novel, low-cost, high-performance VLSI architecture design for MPEG-4 AVC/H.264 CAVLC decoding. We exploit five different techniques to reduce both the hardware cost and power consumption, and to increase the data throughput rate. They are PCCF (partial combinational component freezing), HLLT (hierarchical logic for look-up tables), ZTEBA (zero-left table elimination by arithmetic), IDS (interleaved double stacks), and ZCS (zero codeword skip). The proposed design can decode every syntax element per cycle. The synthesis result shows that the design achieves maximum speed at 175 MHz. When we synthesize the proposed design at the clock constraint of 125 MHz, the hardware cost is about 4720 gates under a 0.18 /spl mu/m CMOS technology, which achieves the real-time processing requirement for H.264 video decoding on HD1080i format video.

A 160K Gates/4.5 KB SRAM H.264 Video Decoder for HDTV Applications

In this paper, a low-cost H.264/AVC video decoder design is presented for high definition television (HDTV) applications. Through optimization from algorithmic and architectural perspectives, the proposed design can achieve real-time H.264 video decoding on HD1080 video (1920 times 1088@30 Hz) when operating at 120 MHz with 320 mW power dissipation. Fabricated by using the TSMC one-poly six-metal 0.18 mum CMOS technology, the proposed design occupies 2.9times2.9 mm2 silicon area with the hardware complexity of 160K gates and 4.5K bytes of local memory

A 7mW-to-183mW Dynamic Quality-Scalable H.264 Video Encoder Chip

A dynamic quality-scalable H.264 video encoder is presented for power-adaptive video encoding. In 0.13mum CMOS technology, it requires 470kgates/13.3kB SRAM and consumes 7mW/183mW in encoding 30fps CIF/HD720 video. Compared to the state-of-the-art design for real-time HD720 video encoding, a 49% reduction in gate count and a 61% reduction in internal memory is achieved

A Dynamic Quality-Adjustable H.264 Video Encoder for Power-Aware Video Applications

This paper proposes a dynamic quality-adjustable H.264 baseline profile (BP) video encoder that comprises 470 Kgates and 13.3 kB SRAM in a core size of 4.3 × 4.3 mm2 using TSMC 0.13 ¿m 1P8M CMOS technology. Exploiting parameterized algorithms for motion estimation and intra prediction, the proposed design can dynamically configure the encoding modes with the design trade-off between power consumption and video quality for various video encoding applications. In addition, the proposed basic unit (BU)-based rate control hardware can maintain a constant and stable bit rate for network video transmission. It achieves real-time H.264 video encoding on CIF, D1, and HD720@30 frames/s with 7 mW to 25 mW, 27 mW to 162 mW, and 122 mW to 183 mW power dissipation in different quality modes.

Magnetic properties, phase evolution, and microstructure of melt spun SmCo7-xHfxCy (x=0-0.5; y=0-0.14) ribbons

Magnetic properties, phase evolution, and microstructure of melt spun SmCo7−xHfxCy (x=0–0.5; y=0–0.14) ribbons via direct quenching have been investigated. For SmCo7−xHfx series ribbons, proper volume fraction of Hf is effective to stabilize and increase the magnetocrystalline anisotropy field of the TbCu7-type structure. Accordingly, the optimal magnetic properties of Br=6.4kG, Hci=7.3kOe, and (BH)max=8.7MGOe could be obtained for x=0.1. Furthermore, a slight C addition to above alloys is helpful in refining the grain size of the ribbons from 100–400nm for C-free to 10–80nm for C-containing samples. As a result, the magnetic properties are further improved to Br=6.9kG, Hci=11.8kOe, and (BH)max=10.6MGOe for SmCo6.8Hf0.2C0.12 nanocomposite ribbons.

Crystal structure and magnetic properties of melt spun Sm(Co,V)7 ribbons

The crystal structure and magnetic properties of melt spun Sm(Co,V)7 ribbons have been investigated. It was found that SmCo7−xVx ribbons may crystallize in pure TbCu7-type structure for x=0.1–0.3 spun at a high wheel speed of 40 m/s. The structure refinement results show that the doping element V prefers to occupy the 2e site of TbCu7-type structure. Besides, transmission electron microscopy images show that with increasing V content, the grain size was refined from 200–400 nm for x=0.1 to 40–100 nm for x=0.3. As a result, the intrinsic coercivity enhances effectively from 1.9 kOe for SmCo7 ribbon to 11.5 kOe for SmCo6.7V0.3 ribbon. It is also verified that a slight addition of C to SmCo7−xVx could further refine the microstructure, resulting in the improvement of the magnetic properties of SmCo7−xVx ribbons. The optimal magnetic properties of σr=58.7 emu/g, Hic=13.5 kOe, and (BH)max=9.3 MG Oe can be obtained for SmCo6.9V0.1C0.1 ribbon.

A Quality Scalable H.264/AVC Baseline Intra Encoder for High Definition Video Applicaitons

In this paper, we propose a quality scalable H.264/AVC baseline intra encoder with two hardware sharing mechanisms and three timing optimizing schemes. The proposed hardware sharing schemes share the common terms among intra prediction of different modes to reduce the hardware cost. The proposed timing optimizing schemes are used to improve the data throughput rate. The proposed design supports different clock rates of 26/33/47 MHz and 70/85 MHz to encode SD and HD720 video sequences with 30fps respectively with different qualities. According to a 0.13¿m CMOS technology, the proposed design costs 170K gates and 4.43 KB of internal SRAM at clock rate of 130MHz.

Magnetic properties, phase evolution, and structure of melt spun SmCo7-xNbx (x=0-0.6) ribbons

The phase evolution, microstructure, and magnetic properties of melt spun SmCo7−xNbx (x=0–0.6) ribbons have been investigated using powder x-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer, respectively. SmCo7−xNbx ribbons could crystallize in TbCu7-type structure only for low Nb substitution of x=0–0.3 at high wheel speed of 30–40 m/s. According to the structure refinement, the doping element Nb prefers to occupy the 2e site. The intrinsic coercivity increases dramatically from 1.9 kOe for SmCo7 ribbon to 10.2 kOe for SmCo6.8Nb0.2 ribbon at wheel speed of 40 m/s. The mechanism of the coercivity enhancement has been discussed. The optimal magnetic properties of σr=54.4 emu/g and Hic=10.2 kOe were obtained in SmCo6.8Nb0.2 ribbon.

A high throughput in-loop de-blocking filter supporting H.264/AVC BP/MP/HP video coding

This paper presents a high throughput VLSI architecture for H.264/AVC in-loop de-blocking filter (ILF) supporting baseline, main, and high profile (BP/MP/HP) video decoding targeted at HDTV applications. We develop a 4times4/8times8 filter and a buffer management scheme to perform the various coding tools in H.264 de-blocking filter for supporting the coding tools of picture adaptive frame/field (PAFF) coding, macroblock adaptive frame/field (MBAFF) coding, and 8times8 transform coding. In particular, we adopt two local buffers to store the reference MB pair data and reschedule the internal pixels when switching the filtering operations on the horizontal and vertical edges without writing it out to the external memory. Adopting TSMC 0.13 mum CMOS technology, we implement the proposed design with the cost of 36.9 K gates and 672 bytes of local memory when operating at 225 MHz. Moreover, the proposed design achieves the data throughput rate of 260 cycles per MB in average, which meets the real-time processing requirement for H.264 16 VGA (2560times1920)@30 fps video decoding.

Improvement of size and magnetic properties of Nd9.5Fe72.5Ti3B15 bulk magnets by Zr or Nb substitution for Ti

Magnetic properties and microstructure of directly quenched Nd9.5Fe72.5Ti3−xMxB15 (M=Nb and Zr; x=0–3) bulk magnets in rod form with a diameter of 0.9 mm have been studied. Proper Nb or Zr substitution for Ti has been found to well modify phase constitution and to refine the grain size from 200 to 50–100 nm effectively. Accordingly, the magnetic properties of the rods are enhanced remarkably from Hic=6.2 kOe and (BH)max=5.6 MG Oe for Nd9.5Fe72.5Ti3B15 to Hic=6.7–15.4 kOe and (BH)max=6.0–8.2 MG Oe for Nd9.5Fe72.5Ti3−xMxB15. The optimum magnetic properties of Br=6.6 kG, Hic=9.6 kOe, and (BH)max=8.2 MG Oe can be achieved for Nd9.5Fe72.5Ti2.5Zr0.5B15 alloy, while the highest coercivity of Hic=15.4 kOe [Br=5.9 kG and (BH)max=7.0 MG Oe] is obtained for Nd9.5Fe72.5Nb3B15. Their high permanent magnetic property arises mainly from the existence of a large volume fraction of 2:14:1 phase, finer grain size, and the existence of grain boundary phase.