Capturing from Video Camera to DP-in on Thunderbolt Mainboard (x299 Deluxe II)

Software & Operating Systems
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1

Hi all, as this is the forum most appreciative of how awesome thunderbolt can be, i turn to you with a somewhat unusual usecase again:

I was wondering whether i can use some software to capture the displayport input used for Thunderbolt video out on my motherboard to capture the video signal of a high quality mirrorless camera without spending 100s of Euros on a capture card.

Where i live webcams are even more obscenely priced than usual so i thought i might as well just get a proper camera and capture the video.

2

Hate to break it to you, but the Thunderbolt controller only passthroughs a DP signal directly to a Thunderbolt port. There’s nothing in the chip so you can capture what’s in that DP stream.

You will still need a capture device. Fortunately the Ultrastudio 3G recorder is a Thunderbolt 3 capture device that should work for this scenario.

3

Oh no! Bad news for me again, but thank you.

Guess i’ll have to get my masters in thunderbolt engineering to bring the features i want to TB5 or 6…

4

Thinking of it, there’s one more thing i don’t understand: There’s a difference between Thunderbolt video and DP Video, which is the reason tb monitors are not “downwards” compatible right? My mobo supposedly supports native thunderbolt monitors, so there would have to be some conversion logic in there, wouldn’t it? Or is thunderbolt video always an embedded DP-Signal unlike usb-c? In that case, why do USB-C notebooks supposedly not work with i.e. the LG Ultrafine TB Displays?

5

USB-C alt mode is different from Thunderbolt display mode. Yeah, that was allowed to happen. For those USB-C alt mode laptops, you need a converter to DP, not Thunderbolt.

6

I updated my question, sry, for the confusion. I meant to ask: isn’t there a thunderbolt exclusive display-protocol the dp gets converted to?

7

For daisy chaining, Thunderbolt muxes PCI-E and DP together to send down the cable. It’s not raw displayport or alt displayport.

DP uses PCI-E for sync, so it makes logical sense to mux it with other PCI-E traffic down one cable.

8

Ah, so one could connect a tb monitor to a usb-c notebook with dp-alt mode support as long as one doesn’t try to daisy chain? And if running via thunderbolt, the monitor extracts the dp signal embedded in thunderbolt?

9

Only the dedicated thunderbolt monitor would be able to get Thunderbolt signals. USB-C alt requires converting from USB-C to full size Displayport. You can also demux with a Thunderbolt dock and you would get raw Displayport that way.