Comparison of high definition optical disc formats Blu-ray disc players since the end of the format war. Blu-ray Disc has a higher maximum disc capacity than HD DVD (50 GB vs. 30 GB for a double layered disc). In September 2007 the DVD Forum approved a preliminary specification for the triple-layer 51GB HD DVD (ROM only) disc though Toshiba never stated whether it was compatible with existing HD DVD players. In September 2006 TDK announced a prototype Blu-ray Disc with a capacity of 200GB. TDK was also the first to develop a Blu-ray prototype with a capacity of 100GB in May 2005. In October 2007 Hitachi developed
Picture disc from the late 1940s through the 1950s. Their most popular and well-known issues resembled Vogue records in their general style of illustration and use of high-quality materials, but they were only 7 inches in diameter, had no reinforcing core disc, and sold for a much lower price. Other companies such as Voco also made picture discs for children. Red Raven Movie Records, introduced in 1956, were a very unusual type of children's picture disc. They featured a sequence of sixteen interwoven animation frames arrayed around the center and were to be played at 78 rpm on a turntable with a