capturing live video feed

[Iain Simons]

Hi there, 

We're working a project where we'd live to feed live video capture into Qlab. 

I'm wondering if anyone had any recommendations as to the best external capture unit? I don't have a tonne of experience in this area, so would appreciate any pointers. Obvs needs to be super-low latency..

Thanks in advance!

-Iaibn

[José Miguel Mayoral]

https://www.magewell.com/products/usb-capture-hdmi-gen-2

Hi! I have been using this model for years and it has never failed.

[Sam Kusnetz]

On Aug 2, 2024 at 12:52:06 PM, Iain Simons <ia...@walthq.com> wrote:

We're working a project where we'd live to feed live video capture into Qlab. 

I'm wondering if anyone had any recommendations as to the best external capture unit? I don't have a tonne of experience in this area, so would appreciate any pointers. Obvs needs to be super-low latency..

QLab directly supports Blackmagic Design video capture devices such as the UltraStudio Mini Recorder and all the PCI cards with the word “DeckLink” in the name. Those are the best low-latency, high-quality options for live video capture into a Camera cue.

QLab also supports anything that appears to the Mac as a USB-connected webcam, including boxes that accept an external camera as the source of video. I’m sure many such devices are great but I have nothing specific to recommend or recommend against.

In a situation where higher latency is acceptable, NDI is also a terrific way to get live video into QLab.

Best

Sam

—

Sam Kusnetz (he/him) | Figure 53

s...@figure53.com

[Paul]

There's a few questions to consider; more than one camera? what camera / interface are you thinking of? What resolution? What is your budget?

The Black Magic UltraStudio Recorder 3G has 1 HDMI or SDI 1080p/FHD input and connects to USB for about $130.  The BM Ultra Studio Mini supports up to 4k with HDMI and SDI inputs connects to USB, with more flexibility and costs around $1000  https://www.blackmagicdesign.com/products/ultrastudio  

SDI will give you lower latency and possibility of longer (coax) cable runs but the latency in the camera and converter will generally be outweighed by the latency of taking the video into the computer. 

So another option to consider is to have a video switch / mixer handling the video and controlling that from Qlab. You can do this with the Black Magic ATEM Mini range which has options with SDI and HDMI and models with 4 or 8 inputs (around $500); https://www.blackmagicdesign.com/products/atemmini 

So you could have your camera going into 1 input and QLab video going into a second and fading between the two using https://www.atemosc.com/  middleware to translate OSC controls.

If you have an NDI camera (LOTS of options these days) then you can feed that directly into computer/QLab via network - I have found newer cameras even using NDI-HX (the compresses version) have much improved latency.

There will be latency at every stage - camera, interface, computer, output display - what is acceptable overall  depends on your show and how you are using the video. . Assuming here you are only sending locally, otherwise other considerations apply. I have done multi-site network camera shows (using Isadora rather than QLab) where we managed audience expectations to get the best result. I think understanding artistic aims before deciding on technology is helpful although it will always be an iterative processes.