Even with compression of the code volume to around 10% through still image compression, only 4.7 x 1024 Megabytes / 3 Megabytes/sec = approx. 1600 sec. = 26 min. 40 sec worth of analog television quality moving color images (720-480 pixels, 256 RGB tones, 30 frames/sec.) can be recorded onto a DVD-RAM (4.7 GB/side). To record content that is around three hours in length, like a movie for example, the code volume of each image frame needs to be further compressed to around 0.5%. To achieve this, in addition to still image compression technology based on the spatial structure of images, technology is also required that addresses the spatio-temporal structures of moving images.