[FFmpeg-user] Blackmagic DeckLink Quad 2

Carl Zwanzig cpz at tuunq.com
Sat Jun 9 00:57:39 EEST 2018

On 6/6/2018 2:52 PM, Robert Frazier wrote:
> And that stream works running on its own too. So my optimistic concern is
> just that I'm using the wrong naming scheme; my only other idea is that I
> can't read two streams from the DeckLink card simultaneously (though I feel
> like I've read I can). 

AFAIK all Decklink Quads can run all four inputs (and outputs) independently 
at the same time. It's easy enough to ask BMD (via their forum or email). 
Their driver version also makes a difference, I think they're at 10.9.11 or 
later now.

Two sources- if the distances are short, you can often split an SDI signal 
with a 'tee' to feed multiple inputs. I've also used the desktop app to feed 
a signal to one output and looped that into another input.

Have you tested each input with the decklink desktop apps? Or by capturing 
each one into a file?

> Another concern is introduced here too: one of my
> streams does not run with frame rate set to 60fps, I need to set it to
> 59.94fps to work, otherwise it is a black screen.

BMD boards are notoriously sensitive to settings (and are they really 60fps 
and not 59.94?).



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