2160p Capture Cards Criteria?

[Badry]

Hello everyone,

 

Following days of painful research in the dark realm of live 4k capturing ,

I would love to start a discussion about the best capture mode for 2160p. 

My workflow consists of receiving a feed from a camera switcher, which is mostly either Sony or Blackmagic switcher.  

It would be great if people who've succeeded in doing this could share their experience, specifically on:

- 4k source mode (single link 12G SDI/Dual link 6G SDI/Quad link 3G SDI), which mode is most common in your market? or perhaps what default output standard is there for a 4k camera switcher?

- 4k colour depth: I read that NO commercial cameras can achieve full 4:4:4 on 2160p, yet some capture cards manufacturer choose to market it, while others get away with selling a maximum capture 2160 @60 on 4:2:0 only. What do you recommend as a minimum acceptable bit depth for a 4k signal?

- What is the minimum acceptable capture delay? the least I found was 64 Video Lines, which if not mistaken translates to 0.5 milli-second. 

- Which Manufacturers have the highest compatibility with the watchout environment?

- Is there an NDI source converter out there that can encode 2160p, and what should be the expected signal delay?

 

The theory surrounding this topic is highly conflicting, it's really hard to separate claims from facts. So really, any insight from a successful experience is highly appreciated.

From what I understood, it is not possible to send "uncompressed RGB"  on links higher than 3G SDI.

Existing 6G & 12G therefore use RAW signals to achieve the transmission. I am not sure what impact does this have on the final outcome and what does it mean for watchout.

 

Thank you all in advance,

Ehsan Badry