HDSD defined

I've never heard of HDSD ... where'd you hearthat term and in what context?

There's SD (standard definaition) and then there's HD (high definition), but no HDSD that I'm aware of. Of course, I could be behind the times.

In general, any video signal of a higher resolution then SD could be called "HD."

-DH

Please don't take this as a personal knock, but you are misinformed. Here's a brief on the subject:

1) Standard Definition is generally what is referred to as uncompressed 601 video. It usually has its source in BetaSP or DigiBeta clips and the frame size is 720 X 486. Bandwidth is usually about 20 MB/sec for 8-bit, or 27 MB/sec for 10-bit. (MB = megabytes. Mb = megabits. 8 Mb = 1 MB.)

2) High Definition has a broader definition, but generally includes frame sizes of 1280 X 720 and 1920 X 1080. Full HD has a bandwidth in the 100+ MB/sec range, even to more than 200 MB/sec. There is also compressed HD, such as DVCPRO-HD and HDV. Those have much lower bandwidth than full uncompressed HD. HDV is 25 Mb/sec at the most.

3) DV is usually 25 Mb/sec (but DVCPRO50 is 50 Mb/sec) and the frame size is 720 X 480. This is typically referred to a DV, not as SD.

Note: #3 above refers to DV-NTSC, not to DV-PAL, which has a frame size of 720 X 576, but is still 25 Mb/sec. (Likewise, #1 refers to NTSC, not PAL.)

Could the confusion have stemmed from the term HD-SDI (High Definition-Serial Digital Interface)? That still has a rate MUCH faster than 15mbps, but hey, it has the initials "HD" and "SD" in it.