ARCHITECTURES: High-def camera is on-chip

Sunnyvale, Calif. — Three veterans of C-Cube Microsystems Inc. have reunited to form a startup that aims to bring consumer cameras into the high-definition era. Ambarella Corp. has a working 17-mm2 packaged system-on-chip that handles H.264 encoding at data rates of 15 Mbits/second and up while consuming just 1 watt.

The 216-MHz A199 chip, now sampling in first-silicon form, can encode both 1,080-interlaced and 720-progressive video and pack an hour of it on a 4-Gbyte flash chip. Combined with falling prices of flash memory and CMOS sensors, the integrated device will open the door to hybrid digital still and video cameras that fit in your pocket, deliver high-def video and sell for less than $800, the company claims.

"We think we can create a low-cost device that changes the price and form factor for this [high-definition camera] market," said Fermi Wang, chief executive of Ambarella and former division manager of C-Cube.

Ambarella's 130-nanometer system-on-chip is going through a design iteration at Taiwan Semiconductor Manufacturing Co. and is expected to be in production by March. At least two OEMs plan to roll out products next year using it.

The A199 handles encoding and all major camera control functions in a single die, including AAC audio and JPEG image codecs. An embedded ARM9 controls the camera, lens, CCD or CMOS sensor, and LCD module. The device also supports USB 2.0, a TV-out function, an IDE interface for hard drives, all major flash formats and 16 to 256 Mbytes of DDR2 memory.

Wang and chief technology officer Les Kohn were working as entrepreneurs-in-residence at Benchmark Capital when they came up with the concept for Ambarella. The duo had worked together at startup Afara Websystems, which designed the Niagara processor acquired by Sun Microsystems Inc. "We knew we didn't want to do another server chip," said Wang.

So the two went back to their earlier collaboration around MPEG at C-Cube to examine the new H.264 spec. The fact that HDTVs are beginning to gain traction as flash prices are falling and digital cameras are becoming mature also played into their thinking. "All these things merged for us at one point," said Wang.

Ambarella analyzed cost vs. performance trade-offs for the more than 15 distinct tools that are part of the H.264 main and high profiles to determine an optimum implementation before starting work on the chip's architecture. "We had a very good idea of what we wanted to do before we started the design," Kohn said.

Many MPEG-4 profiles implement only a few compression tools and may actually be less effective than versions of MPEG-1 and -2. "For our customers, H.264 Main Profile is required, and you have to implement all the tools," said Wang.

Ambarella is claiming "kind of a breakthrough in implementing HD encoding with significantly less memory bandwidth than competitors," said Kohn. The company has submitted a patent on its approach that can use as little as one 16-bit DRAM.