Sony's digital version of its Betacam videotape format. Introduced in 1994 using 10-bit DCT compression and 4:2:2 sampling, Digital Betacam has been widely used for standard-definition video recording. L (Long) cassettes hold 124 minutes of video and four channels of 16-bit audio. Many digital VTRs from Sony play back all Sony digital and analog Betacam formats (see
Betacam).
Betacam SX
Targeted at news production in 1996, Betacam SX offered greater efficiency than Digital Betacam. Using 8-bit MPEG-2 at 4:2:2P@ML sampling and a low 18 Mbps bit rate compared to 90 Mbps for Digital Betacam, Betacam SX provided up to 194 minutes on an L cassette. It introduced the capability of tagging scenes, letting the camera operator mark good shots so they can be selectively retrieved on the VTR.
MPEG IMX
Supporting the same 4:2:2P@ML sampling as Betacam SX and the MXF video file interchange format, MPEG IMX was introduced in 2000 to take Betacam into the networked A/V post-production world. MPEG IMX supports eight channels of 16-bit audio. Bit rates from 30 to 50 Mbps are higher than Betacam SX and lower than Digital Betacam. See
Betacam and
SD formats.