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Deciphering exclusive modes in the spec sheets?

PostPosted: Sat Jun 22, 2019 4:56 pm
by Chad Capeland
I see this in a bunch of BMD products, and I'm wondering if there's a trick to determining which specifications are exclusive of one another.

In the exact case I'm looking at today, I see the Decklink 8K Pro says it does DCI 4Kp120 3D and it does 12b 4:4:4 rec 2020 and it does bidirectional 12g SDI connections.

If all three of those are non-exclusive, that means I can hook up 4 DCI4K cameras as two stereo pairs running at 120fps at 12 bit in RGB. For US$650. If it sounds too good to be true... there's got to be a catch, right?

So is it true? Or if not, what modes are exclusive, and is there a way I or a reseller can figure what combinations are valid using an excel sheet or some online configurator?

Re: Deciphering exclusive modes in the spec sheets?

PostPosted: Wed Jun 26, 2019 2:11 am
by Dave Del Vecchio
12-bit 4:4:4 requires double the bandwidth of 10-bit 4:2:2. So a single 4Kp60 signal at 10-bit 4:2:2 requires 12Gbps, but at 12-bit 4:4:4, 24Gbps is required (which would mean two 12G SDI cables).

Similarly 120fps requires double the bandwidth of 60fps, so a 4Kp120 signal at 10-bit 4:2:2 would require 24Gbps. Going up to 12-bit 4:4:4 would double things again, so 4Kp120 @ 12-bit 4:2:2 would require 48Gbps or four 12G SDI cables.

If you look at page 9 of this PDF, there is a chart with some common video standards and the bandwidth required for each:
https://www.smpte.org/sites/default/fil ... 3-Full.pdf

Re: Deciphering exclusive modes in the spec sheets?

PostPosted: Wed Jun 26, 2019 10:13 pm
by Chad Capeland
Thanks for the link.

So based it the product spec sheet saying it supports dual and quad-link, we would be able to do dual-link 4Kp60 12b 4:4:4 with the stereo pair on the second dual-link input. Pretty impressive.