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Quad-Link 4 different signals

PostPosted: Thu Dec 07, 2017 8:54 am
by Asgeir Hustad

I was wondering if it is possible to use a Quad-Link to 6G-SDI-converter to link 4 different HD-SDI-signals? In theory, if all sources were genlocked to the same reference, I imagine it could work, but I wouldn't bet $1000 (the cost of the converters) on it just yet :D ... #W-CONM-14

I was planning on using it for a fiber-optical stage-box, where four cameras were converted to one SDI-link, then using one BMD SDI->Optical on each end and a new De-Multiplex in the control room, where the inputs would go to the switcher. This would mean I could get 4 lines each way on each fiber core - and save some cores for audio, intercom, reference etc.

Re: Quad-Link 4 different cameras

PostPosted: Thu Dec 07, 2017 9:45 am
by Xtreemtec
It won't work. As you get screwed up by payload id's.
In SDI you have Payload id's. This defines what type of signal is send. Defines resolution, framerate etc etc.

In quadlink you have 4 payload id's that match. Defining each 1 quarter of the screen. The quadlink receivers can even make out which quadrant is connected to which connector and will auto align the 4 quadrants.

I also wonder what will happen to audio, ANC data and stuff if it was even possible.. As in a 6G or 12G signal there is only 1 ANC data 1 Audio source etc.. ;)

What you need is a fiber video mux and demux. These have 4 independend lines going over 1 fiber.
Take a look at the Mux/Demux One here

Re: Quad-Link 4 different signals

PostPosted: Thu Dec 07, 2017 11:47 am
by Asgeir Hustad
Yeah, I was assuming something like that. All right, I'll keep on saving for a fiber mux/demux - or maybe just upgrade from 4-core to MTP :D

Re: Quad-Link 4 different signals

PostPosted: Sun Dec 10, 2017 4:24 pm
by Fred Rodrigues
I just made some tools for an installation that used exactly this. I was not aware about the metadata quadrant tag, maybe it is not strictly enforced yet. I was able to send 4 HDSDI signals to a quad input (decklink 4k card with mezzanine card for quad SDI), at a variety of rates (25, 30 50 and 60p UHD). The only obvious, thing is that all the signals need to be locked to the same reference. I did notice that the mezzanine card seems to have different SDI drivers and cables that work fine with the main card give spotty signals on the mezzanine card. Otherwise it seems the metadata is not strict for the time being and this solution (at 12g anyway) worked fine.

Re: Quad-Link 4 different signals

PostPosted: Sun Dec 10, 2017 4:34 pm
by Xtreemtec
Well maybe some software solution won't mind..
But some hardware could be very easily expect only this type of signal..

But what happend to the ANC and Audio data in your case then?

Re: Quad-Link 4 different signals

PostPosted: Sun Dec 10, 2017 4:40 pm
by Fred Rodrigues
I was not using either, it was a fast solution real time manipulation. It was accepted fine by media express and the deck link SDK in general. As far as I know the ANC data is sent via quadrant 1.