HD DVD May 2008, both companies announced they would stop manufacturing dual-compatibility drives. A few computer manufacturers (such as HP and Acer) sold computers with combination HD DVD/Blu-ray Disc drives. LG marketed a Blu-ray writer that also read HD DVD discs (but could not write to them). HD DVD competed primarily with Blu-ray Disc. Both formats were designed as successors to DVD, capable of higher quality video and audio playback, and of greater capacity when used to store video, audio, and computer data. Blu-ray Disc and HD DVD share most of the same methods of encoding media onto discs with each other,
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