Optical disc the DataPlay format, can have capacity comparable to that of the larger, standard compact 12 cm disc. Third-generation optical discs are in development, meant for distributing high-definition video and support greater data storage capacities, accomplished with short-wavelength visible-light lasers and greater numerical apertures. Blu-ray Disc and HD DVD uses blue-violet lasers and focusing optics of greater aperture, for use with discs with smaller pits and lands, thereby greater data storage capacity per layer. In practice, the effective multimedia presentation capacity is improved with enhanced video data compression codecs such as H.264/MPEG-4 AVC and VC-1. The following formats go beyond the
Optical disc packaging for DVD-Audio, and as of mid-2006, the case format for all albums released by the Universal Music Group in Europe. Many alternatives to the standard jewel case may also be found, including larger DVD-style cases with a more book-like shape. It is not uncommon to find CDs housed in custom cases, tins and boxes of varying shapes and sizes. Slipcases and other envelope-type designs are also occasionally used. Some DualDiscs are packaged in jewel cases of a somewhat different design from the CD version; the inside edge is rounded instead of flat, and the physical position of the disc is