To quote an old, old line, the best thing about standards is that there are so many of them. High definition TV is no exception. The simple (?) acronym
HD-SDI is actually a catch-all for a confusing brace of standards. Here, for my convenience, several are itemised (along with some that aren't HD in the firmly old-school, 1940s sense.) First,
SMPTE:- SMPTE 170M
- NTSC (Analog composite)
- SMPTE 240M / 260M
- 1125i
- SMPTE 274M
- 1080i & 1080p
- SMPTE 296M
- 720p
- SMPTE 259M
- SD-SDI (ie. the serial interface itself)
- SMPTE 292M
- HD-SDI (likewise)
- SMPTE 372M
- Dual-link HD-SDI
- SMPTE 272M
- SDI Embedded audio
- SMPTE 299M
- HD Embedded audio
And then ITU (previously EBU, previously various others...):
- ITU-R BT Rec 601
- SD PAL digital coding
- ITU-R BT Rec 709
- Erm...
So, that's neither exhaustive nor correct. I'll update it one day. Perhaps.