Variants
Mini Blu-ray Disc:-
The Mini Blu-ray Disc (also, Mini-BD and Mini Blu-ray) is a compact 8cm (~3in) diameter variant of the Blu-ray Disc that can store approximately 7.5GB of data. It is similar in concept to the MiniDVD.Recordable (BD-R) and rewriteable (BD-RE) versions of Mini Blu-ray Disc have been developed specifically for compact camcorders and other compact recording devices.
BD9 / BD5 Blu-ray Disc:-
BD9 and BD5 are lower capacity variants of the Blu-ray Disc that contain Blu-ray compatible video and audio streams contained on a conventional DVD (650 nm wavelength / red laser) optical disc. Such discs offer the use of the same advanced compression technologies available to Blu-ray discs (including MPEG4-AVC/H.264, SMPTE-421M/VC-1 and MPEG2) while utilizing lower cost legacy media. BD9 utilizes a standard 8152MB DVD9 dual-layer disc while BD5 utilizes a standard 4489MB DVD5 single-layer disc.Given that Blu-ray Discs are assumed to have a minimum transfer rate of 30.24 Mbit/s, BD9/BD5 discs must be spun at a high rate of speed, equivalent to a 3× DVD drive speed or greater.BD9 and BD5 discs can be authored using home computers for private showing using standard DVD±R recorders. AACS digital rights management is optional.The BD9 format was originally proposed by Warner Home Video, as a cost-effective alternative to regular Blu-ray Discs.It was adopted as part of the BD-ROM basic format, file system and AV specifications.BD9 is similar to HD DVD’s 3x DVD.
AVCREC:-
AVCREC is an official lower capacity variant of the Blu-ray Disc used for storing Blu-ray Disc compatible content on conventional DVD discs. It is being promoted for use in camcorders, distribution of short HD broadcast content and other cost-sensitive distribution needs. It is similar to HD REC for HD DVD.Note that AVCREC is not the same as AVCHD content stored on DVD. The latter is a media independent format that originated prior to the release of Blu-ray Disc.