AVCHD uses the MPEG4 AVC/H.264 compression system, which is more efficient than the MPEG2 system used on conventional DVDs. As HD video contains about four times as much picture data as standard definition video a better compression system is essential if anything more than a few minutes of video is to be stored on each disc.
Yoshikazu Ochiai, a spokesman for Sony in Tokyo, said that despite the present focus on Blu-ray Disc, the format is currently not feasible for camcorder use. Several hurdles remain before Blu-ray Disc drives can be fitted into camcorders, including bringing down the price of the drive, making it small enough to fit into a camcorder, and reducing energy consumption.
Using AVCHD, about 20 minutes of HD video can be recorded on a single-sided DVD disc when using the average quality setting, said Ochiai. That compares to about 30 minutes of video when using the same disc with a standard definition camcorder.
Sony is already developing a camcorder based on AVCHD but Ochiai wouldn’t provide any details. He did not explain what the acronym AVCHD represents.
The company’s current consumer HD camcorders use the cassette-based HDV system, which stores HD video on conventional MiniDV cassettes. Each tape can hold up to 60 minutes of video so it beats AVCHD in recording time but the new optical-disc system has its own advantages. A major one is random access. Because it’s an optical disc data can quickly be accessed quickly from anywhere on the disc and so calling up recorded scenes is much faster than tape.
It will also be possible to read the discs in current DVD drives such as those in PCs or DVD players, however AVCHD software will be needed in order to playback content stored on the discs. This is much the same as DVD Video discs, which can be read in PC drives but not played without DVD player software.
— Martyn Williams (IDG News Service)
[Via Digital World Tokyo ]