HD-SDI Wish list

S

sonisfear

Well-known member
Well it seems that HD-SDI is the format that is staying. If anyone has a connection to the forum were they design and decide what goes into could you pass on this wish list.

since w are wiring one cable for to the cam that house the RGB, genelock and audio. Could the add COM as well. It dosen't hafto to be 24bit 96khz audio I think 8 bit 22khz full duplex is enough.

For cams like the XL G1 a firmware upgrade could give you the option of using the headphone jack on the cam for com and one of the mic inputs as com return. Most live event dosen't use stereo audio from the cam anyway. In the case of the XL g1 the MA-300 gives you addition 2 for a total of 4 mic inputs.

Tally would be nice as well using the oncam Tally light.

1080P bandwidth would be aesome but I am not expecting this one to happen soon.

The these Switch/mixer manufactures need to get onboard and have the switcher access the CCU console functions and transmit the Tally and the com (just needs a com input the com bay station could do all the matrixing).

Just my humble ideas
 
I think you may have mis-understood the (HD)SDI signal.

SDI is "Serial Digital Interface" and it carries just video, timecode and embeded AES/EBU audio in one direction. It's basically an industrial version of firewire, thoguh it's one direction only, but can go much furthur and has mcuh lighter compression (including some uncompressed modes).

SDI does NOT carry Genlock information.

To transmit bi-directionally down a single signal path (such as a single-wire cable) you need to "multiplex" the signals together and modulate them onto carriere frequencies such that can exsist in the same medium at teh same time.
There is allready a profesional interface in place that does jsut this: It's called TRIAX. It's a 3-conductor cable (like Coax, but with another layer on the outside) that carries power and all the signals on one line. Most camera manufacturers (Sony, Panasonic, Thompson Grass Valley, Hitachi, etc..) have their own Triax systems. Most of which are supprizingly enough, Analog!

There are also Fiber systems beeing deployed to perform the same and meet HD handwidth specifications.

SDI is used profesionaly as a A/V transfer signal. But to carry CCU/RCU control, Comm, Tally, Return Video & Audio, Etc.. (including Power) you need a much more complex system like Triax.

There are also lower end systems, such as the Camplex system (www.camplex.com) which is avaialble in both SD and HD Analog & Digital versions.

- Mikko
 
HD-SDI _DOES_ carry an uncompressed data stream. I am aware of no compressed data signal that travels over HD-SDI.

There are near relatives of it - HD-SDTI that carries Sony's proprietary HDCAM data format, and there is HSDL for transmitting uncompressed 2K & 4K film scan style frames, but HD-SDI is for carrying baseband (uncompressed) signals.

Period.

(At least AFAIK.)

-mike, hdforindies.com
 
I thought that basic SDI & HD-SDI where 4:2:2 subsampled? Matching DigiBETA and digitally replacing Component (and BETA-SP).

And that only only Dual-link HD-SDI was 4:4:4

- Mikko
 
Thanks for you information Mikkowilson and Mike curtis,

I could understand not sending power through the coax but CCU control (I am thinking of the console software that comes with the canon XL series) is only a few bytes sent the other way and com if in low rez could be data efficient as well.
 
Yeah, but even the slightest amount of info sent "the other way" will need a bi-directional system. SDI is one way only.

- Mikko
 
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