Q: What specifications govern BD discs?

A: All BD disc formats are governed by a variety of system descriptions (books) defining their mechanical properties, optical signal characteristics, physical arrangement, writing methods and testing conditions as well as file systems and applications. Specifications for BD physical formats (BD-ROM, BD-R, BD-RE and BD Hybrid) and applications (BD-R/RE AV and BD-ROM AV incorporating HDMV and BD-J modes) were established and are continually updated by the Blu-ray Disc Association (BDA), an alliance of manufacturers founded in 2002 by Hitachi, LG Electronics, Matsushita Electric, Pioneer, Philips Electronics, Samsung Electronics, Sharp, Sony, and Thomson. Currently, there are no plans to develop BD specifications into ECMA International or ISO/IEC standards.