The A390, from Ambarella Inc., is a system-on-a-chip (SoC) that simultaneously captures 8 Mpixels still pictures while generating and compressing high-definition (HD) video in either 1080p60 or 1080i60 formats. The device stores still images in either RAW or compressed formats, implementing the JPEG standard at a rate of one picture per second without interrupting full HD-video recording. Working at a data capture rate as fast as 480 Mpixels-per-second, the A390′s speed exceeds 60 frames-per-second at 8 Mpixels. The A390 SoC is the third member in the A3 SoC platform series targeted at hybrid cameras and supports the emerging H.264 AVC video standard. The Ambarella A390 SOC is designed for hybrid cameras. The A3 platform is available in multiple configurations for various requirements. Evaluation kits for both products are available now.
Full Sensor Resolution Video Capture
The A390 captures data as fast as 480 Mpixels/s, which is a rate in excess of 60 frames per second at 8 Mpixels. As is common in digital still cameras (DSC) and in most HD camcorders, a single color filter array sensor (Bayer RGB) generates red, green and blue (RGB) primary colors. The A390 converts data from Bayer pattern to RGB (called de-mosaicing) at a very high rate, resulting in a virtually artifact-free and full-resolution video signal. This kind of processing is more accurate in terms of clean edges with no Bayer artifacts than the simple binning combination of adjacent pixels commonly used in many camcorders. The A390 yields a higher-resolution output than the extrapolative techniques used with three sensors (3 CCD).
HD Hybrid Camera SoC and Progressive Video
The A390 HD chip enables the development of full high-resolution cameras at the highest-image quality with smooth 60 frames/second video and simultaneous recording of high resolution stills. Ambarella’s A390 integrates an H.264 codec capable of encoding full 1080p60 at 1920 pixels per line resolution – 124,416,000 pixels per second. The programmability of the Ambarella platform enables implementation of multiple formats for HD video, such as the AVCHD specification for 1080i HD camcorders, as well as many formats commonly used on personal computing platforms.
JPEG and Loss-less RAW compression
The A390 integrates an advanced high-performance image-processing pipeline, still image compression using both loss-less (RAW) and loss-y (JPEG) formats, audio compression and all key system functions.
Motion Compensated 3D Noise Reduction
Depending on the amount of light available, imaging sensors can have a substantial amount of noise, and filtering this noise is critical for producing high-quality images. The challenge of a full-resolution HD camcorder is to reduce the noise without causing a loss of resolution or a loss of detail, so advanced spatio-temporal (3D) filters must be used. Most available solutions are motion adaptive and switch from a predominantly temporal to a predominantly spatial filter based on detecting the presence of motion. Because Ambarella’s A390 SoC is motion compensated instead of just motion adaptive, it truly tracks the motion and uses motion compensation in the filter.
3D Image Registration
The high capture rate of the A390 – as high as 480 Mpixels/sec – allows a new approach to low-light photography. Instead of capturing a single image in low light with a long exposure that results in a blurry picture, the A390 captures image sequences with short exposures. This approach combines, or registers, multiple images within the sequence to create a sharp, low-noise picture. This is the still-image equivalent of motion compensated 3D noise reduction.
More info: Ambarella