Sony has developed what it says is the smallest high-definition video camcorder in the world and plans to put it on sale in Japan later this month and in the US in May.

The HDR-TG1 is 32 millimeters thick by 119 millimeters high by 63 millimeters wide and weighs 300 grams. It's a tall and thin camcorder with a fold-out display -- a design along the same lines as Sanyo's Xacti line of high-def camcorders, but the Sony camcorder is about two-thirds the volume of Sanyo's latest full high-def model.

One of the secrets of its thinness is the lack of a DV tape desk, hard-disk or optical drive. Instead the TG1 records to a Memory Stick Pro Duo or Pro-HG Duo memory card.

The camera lays down AVCHD format video at 1,920 by 1,080 resolution (so-called "Full HD"). AVCHD is a high-def format developed by Sony and Panasonic that's designed to provide some compatibility between camcorders and living room disc players and other entertainment hardware.

In the highest quality "FH" mode, which is full HD resolution at 16M bps, the supplied 4G-byte card will be able to store 25 minutes of footage. This lengthens to 55 minutes in HQ mode, which records a 1,440 by 1,080 resolution image at 9M bps. The SP and LP modes record drop the video bit rate -- and thus the quality -- to 7M bps and 5M bps, respectively and result in 65 minutes and 85 minutes of recording time.

As with other card-based cameras, higher capacity cards mean more recording time.

In addition to video the camcorder can also take 4-megapixel resolution still images. Like some of Sony's still cameras the TG1 has face detection and can track up to eight people in the shot.

Other features include an optical 10X zoom, 2.7-inch widescreen touch panel LCD monitor and HDMI connector.

It will be available in Japan from April 20 and will cost around US$1,300.