Technology : Video camera that packs 'em in

时间:2019-02-27 09:19:01166网络整理admin

By Barry Fox Tokyo AFTER a brief accord, a battle over competing standards has begun between electronics companies manufacturing digital video cameras. Hitachi has broken away from the pack and launched a new camera that records video in a format already widely used for multimedia CDs. Hitachi previously agreed with the other big manufacturers to develop cameras to a standard known as DVC. Three companies—JVC, Sony and Panasonic—have already launched DVC cameras. But Hitachi has now opted for a camera that relies on the powerful MPEG compression technology. The MPEG compression standard, originally devised for storing video on CDs, is widely used for playing back multimedia material on personal computers. Until now, the electronics needed for MPEG compression have been too unwieldy to be used in a small consumer camera, but now Hitachi has succeeded in integrating all of the 300 000 components needed for MPEG coding into a single chip that consumes only 600 milliwatts. The MPEG camera, shown for the first time at a demonstration in Tokyo this month, weighs only 540 grams and looks like a rotary-head shaver. The head has a high-resolution video camera lens on the front and a colour LCD viewfinder screen on the rear. Inside the handle there is a slot for a miniature hard disc drive of the type now standard for notebook computers. The disc stores moving videos of a quality better than VHS, still pictures, or hi-fi sound. Images can be played back through the camera’s LCD, or by plugging it into a TV set. Alternatively, the hard disc can be plugged into a computer and the data viewed there. MPEG was designed to make digital movie players simple and cheap, but until now it has required whoever is making the recording—typically the film studios—to use massive processing power to compress the video. Hitachi’s chip changes all that. The MPEG standard compresses video by a factor of around 100 by comparing groups of up to 15 pictures at a time and coding only the differences between them. It needs a data handling capacity of only 1.5 megabits per second. The compression system used in a DVC camera codes each picture individually. This keeps the recording circuitry much simpler than the MPEG equivalent, but generates around 20 times as much data to describe the same video sequence, so the camera consumes a lot of tape to make a recording. Hitachi already makes miniature hard disc drives, which plug into portable computers and look like a thick credit card. The MPEG camera takes a 260-megabyte drive that stores 20 minutes of video, or a hefty 340-megabyte version that stores 30 minutes. The single Hitachi chip can also compress still pictures to the JPEG standard, which is widely used to store photographs on a PC or send them over the Internet. The camera can record up to 3000 still pictures. Alternatively, it can record four hours of sound. Access to a selected sequence or still on the hard disc is virtually instantaneous. “We have no need for DVC,” says Norio Ogimoto, head of Hitachi’s products planning group in Japan. “All future multimedia products must be based on MPEG,