Sony's digital version of its Betacam videotape format. Introduced in 1994 using 10-bit DCT compression and 4:2:2 sampling, Digital Betacam was widely used for standard-definition video recording. L (Long) cassettes held 124 minutes of video and four channels of 16-bit audio. Today, Digital Betacam is mostly used to play archival footage, and many Sony VTRs support all Betacam formats (see
Betacam).
Betacam SX
Targeted at news production in 1996, SX offered greater efficiency. Using 8-bit MPEG-2 sampling and a low 18 Mbps bit rate compared to 90 for Digital Betacam, SX provided up to 194 minutes on an L cassette. It also allowed the operator to tag good shots so they could 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 were higher than Betacam SX and lower than Digital Betacam. See
Betacam and
SD formats.