The recorders can cram up to 18 hours of high-definition video onto a 50G-byte Blu-ray Disc -- something that hasn't been possible until now.
Previous recorders took the MPEG2 digital TV stream as it was transmitted and recorded it directly to disc resulting in a recording capacity of about 4 hours on the 50G-byte discs. However, the development of chips that can convert the 17M bps MPEG2 stream in real-time to the more efficient MPEG4 AVC compression system has realized this greater storage capacity on each disc.
In addition to disc recording, the machines can also store video on built-in hard-disk drives. The DMR-BW900 has a 1T-byte drive, which offers enough space for between 160 hours and 381 hours of high-def video depending on the MPEG4 AVC recording mode in use. In contrast the same drive can store 127 hours when the MPEG2 stream is unchanged.
The DMR-BW800 has a 500G-byte drive and the DMR-BW700 has a 250G byte drive. All three recorders will go on sale in Japan on Nov. 1. The top-of-the-range BW900 will cost %300,000 (US$2,600), the BW800 will cost %230,000 and the BW700 will carry a %180,000 price tag.
There are no immediate plans to sell them overseas but Panasonic said it is examining the possibility.
Sony, like Panasonic, also has the MPEG4 encoding capability to more video can be stored on each disc and machines from both companies offer a 4X transfer mode for pulling video from the hard-disc to the Blu-ray Disc. The highest capacity Sony recorder has a 500G-byte drive while Sharp, like Panasonic, has a model with a 1T-byte drive. The Sharp machines don't feature the MPEG4 encoding ability.