D-2
(Digital-2) A 3/4" (19mm) broadcast-quality composite digital videotape format designed for recording uncompressed digital versions of analog NTSC or PAL. D-2 was developed to lower the storage and transfer costs of D-1, which encodes component video.
D-2 VTRs sample composite video at four times their subcarrier frequency (4FSC). D-2 VTRs use the same cassettes as D-1, but the formats are not interchangeable. D-2 was not a popular format. See D-1 and SD formats.