What rotational schemes do BD discs employ?
BD-ROM/R/RE are currently read and written using Constant Linear Velocity (CLV). As is the case for CD and DVD, Constant Linear Velocity (CLV) maintains an even data transfer rate as the optical head of the recorder, drive or player reads or writes from the inner (ID) to outer diameter (OD) of the disc. At 1x, the rotational speed of a BD disc decreases from roughly 1957 RPM to 810 RPM (ID to OD) to maintain a constant linear velocity of 5.280 m/s (23.3 GB disc) or 4.917 m/s (25 GB disc). [Top of page] [BD FAQ home][EMedialive home] How much time does it take to write a BD-R and BD-RE disc? BD-RE was first introduced to market with 1x (CLV) writing but both BD-RE and BD-R specifications now define 1x and 2x (CLV) operation. Since 1x BD writing transfers 4.29 MB (4,495,625 bytes) of data per second it takes, roughly, 93 minutes to write a full 25 GB disc or 46 minutes at 2x [(25,025,315,816 bytes ÷ 4,495,625 or 8,991,250 bytes per second) ÷ 60 seconds = 92.78 or 46.39 minutes]. In pract
