SMPTE D-3 Video Format
SMPTE D-3 Format Information:
Videotape Format: SMPTE D-3 Composite Digital
In use: 1991-Present (in limited venues)
Recording mode: Composite digital video, helical scan. 4 channels of AES/EBU PCM format audio, sampled at 48 kHz. Time code channel.
Tape width: 83.88 mm
Features: Uncompressed composite digital VTR.
Existing machine longevity: A few machines are maintained for remastering purposes.
Videotape longevity: Unknown.
Prior usage: Another alternative for analog VTR’s such as one-inch C. Also gave the opportunity for lossless “clones” or dubs from one tape to another, in digital form.
Notes on the SMPTE D-3... The D-3 format was a competitor to the Sony D-2 format, introduced as few years earlier. Panasonic had several models of this format over the years (such as the AJ-D350 and AJ-D360), as did Sony with D-2. Major network delivery requirements for programs on composite digital, appeared to be as follows: NBC & PBS: D-3, CBS & ABC: D-2.
The difference between component digital (D-1) and composite digital (D-2 and D-3), was that the input to these formats was an encoded NTSC signal, sampled at 4fsc, as opposed to a discreet component signal consisting of RGB (uncomposited NTSC) video. Both were workable formats, but D-1 was technically superior as all video processing was in the raw, component form. For example, a chroma key could be manipulated much easier in D-1 with discreet RGB. In D-2, even though it was a high quality signal, the composite digital stream had to be decoded into RGB for processing, which in itself was a somewhat bandwidth limited video element, due to prior NTSC encoding.
D-3 is in less use for production/post production now. But tapes still exist in archives, along with D-1 and D-2, etc.
It should be noted that Panasonic continues to build and sell the D-5 HD format (based on the D-3 transport), which is currently in high demand for many aspects of high-definition television.