Panasonic HS camcorder, the HS20 uses a hard disk for recording, with a slot for SD memory also available. The hard disk has a healthy 80GB capacity, and uses the AVCHD format for recording. The same compression options are available as other recent Panasonic HD camcorders, with the top HA mode using 17Mbits/sec. So the hard disk is enough for over 10 hours of footage