DVD CDs (0.74 µm for DVD versus 1.6 µm for CD), accounting in part for DVD's increased storage capacity. In comparison, Blu-ray Disc, the successor to the DVD format, uses a wavelength of 405 nm (violet), and one dual-layer disc has a 50 GB storage capacity. Read and write speeds for the first DVD drives and players were 1,385 kB/s (1,353 KiB/s); this speed is usually called "1×". More recent models, at 18× or 20×, have 18 or 20 times that speed. Note that for CD drives, 1× means 153.6 kB/s (150 KiB/s), about one-ninth as swift. DVD-Video is a standard
Nintendo optical discs Optical Disc" (RVL-006) is the physical game medium for the Wii, created by Panasonic. Nintendo extended their proprietary technology to use a full size 12 cm, 4.7/8.54 GB DVD-based disc, enabling it to have the benefits of the GameCube Game Disc, while having the standard capacity of a double-layer DVD-ROM. Although the Wii can use double-layer discs, all titles were single-layer prior to the release of "Super Smash Bros. Brawl". With the release of "Super Smash Bros. Brawl", Nintendo admitted that some Wii systems may have trouble reading dual-layer discs due to a dirty laser lens. Nintendo repaired systems with