HD DVD BD9 formats. HD Rec is an extension of the HD DVD format for recording HD content on regular red laser DVD-Rs/DVD-RWs using H.264/MPEG-4 AVC compression. It was approved by the DVD Forum on September 12, 2007 It is comparable to Blu-ray Disc's AVCREC. The China Blue High-definition Disc (CBHD), a high-definition optical disc format, was based upon the HD DVD format. Like the HD DVD, CBHD discs have a capacity of 15 GB single-layer and 30 GB dual-layer and can use existing DVD production lines. Unlike the HD DVD format, industry support for this format has grown steadily. HD DVD
Optical disc authoring recorders. There are, however, stand-alone devices like personal video recorders which can also author and record discs. Use of optical disc recorders require "optical disc authoring software", sometimes called "burning applications" or "burner applications". Such software is usually sold with the recorder. Some operating systems come bundled with them. Creating an optical disc usually involves first creating an optical disc image with a full file system designed for the optical disc, and then actually burning the image to the disc. Many programs create the disc image and burn in one bundled application (Quick Copy or Copy On-the-fly), such that end-users