Bringing Video in from another computer

B

Brad Morris

New Member
Like many others, we are a church that has started live streaming our services. I have a sound board, Digital HD Camera with video captured through Black Magic USB3, and a web cam. Everything works. We now want to bring video (VGA now but converting to HDMI in several months) from another computer in as another scene. SO on the streaming (OBS) computer I have a camera on the pastor or worship team. On the second computer (our presentation computer) we have our slides and videos. I want to be able to send the output of that computer to the OBS computer for Facebook.
What do I need to get the other computer video to our streaming computer (OBS)? Do I need another capture device? If so, can it be a second Black Magic USB3 or does it have to be different?
Thanks in advance!
 
Brad,

NDI will do want you want. The best part is that it is free.
My first question is what is your presentation software? It may have a NDI output option.
If not, you can download NDI-scan converter to your presentation computer and have it capture and send out your slides.
After you get your presentation computer sending out via NDI your slides, you just add a NDI source to your OBS computer.

You will need a gigabit network connection to make NDI work well.

Free NDI tools can be downloaded here: https://ndi.tv/tools/
 
PabloPickaxe said:
Looking for the same thing, but the other computer I'm using as a camera is a chromebook. Will this work?
Click to expand...
Depends on the model, but Chromebooks are notoriously underpowered, and IIRC are not supported by OBS or Newtek (who are the primary developer for NDI in general). You may need to use OBS.Ninja instead, or to grab a capture device like the Elgato Camlink or HD60S+.
 
FerretBomb said:
Depends on the model, but Chromebooks are notoriously underpowered, and IIRC are not supported by OBS or Newtek (who are the primary developer for NDI in general). You may need to use OBS.Ninja instead, or to grab a capture device like the Elgato Camlink or HD60S+.
Click to expand...
Thanks, that's really helpful!
 
Similar configuration on my side

here are the details:
- 2 MacBook (one of the last generations)
- presentation software used the second computer: PPT / Keynote
- the presentation file on the second computer can't be transferred to the first/main computer
- the ffirst/main computer is running OBS to live stream and record.

Would NDI work ?

thx
 
I posted elsewhere on this, but I'm using NDI screen capture with the NDI plugin (latest version of everything), and this works great for PowerPoint slides, but when somebody is running a video clip on the laptop that I'm capturing from, OBS memory usage keeps climbing over several minutes until memory is exhausted. Has anybody else seen this? Memory usage is on the streaming computer and NOT on the laptop I'm capturing from. It's like it's buffering but never letting go.
 
Hi All! As tis option have not been mentioned, this is what we do in church:
As original poster, we have a presentation laptop. That video is sent to streaming pc via a hdmi splitter into HDMI capture card (this can be usb or card type).
I think this is the most simple solution as there is no additional strain on network, or presentation laptop.
Josh
 
Josh75 said:
Hi All! As tis option have not been mentioned, this is what we do in church:
As original poster, we have a presentation laptop. That video is sent to streaming pc via a hdmi splitter into HDMI capture card (this can be usb or card type).
I think this is the most simple solution as there is no additional strain on network, or presentation laptop.
Josh
Click to expand...
I agree with that! With some caveats:

Cheap capture cards are cheap for a reason. The common problems are:
  1. Deceptive design and marketing. It may have a USB 3 connector and be sold as USB 3, with all the comparisons to USB 2 that go along with that......but it's actually a USB 2 chip inside! That works because USB 3 *includes* USB 2 for backwards compatibility, in addition to the much better stuff that it's also capable of. But because the chip inside is USB 2, you can't actually use that. You're stuck on USB 2, despite having a USB 3 connector and advertisement.
  2. Because of #1, it can't actually give you uncompressed HD video. It *must* compress, *in the card*, before it can stuff it through the wire. The practically universal compression method is MJPEG, which is simply a JPG image of each frame, with no knowledge of the other frames. So if you've seen the "JPG fuzzies" on a still image, that's what it's doing to your video. It's not as noticeable for a camera as it is for computer-generated content like a PowerPoint slide or similar, because JPG is designed for real-world photographs, but it's still there.
  3. Random latency. I don't really know why this happens, but I do know from direct experience that it does. A previous iteration of my church's rig had 4 cheap HDMI -> USB captures. Two for cameras, one for another computer, and one spare. They were *always* out of sync with each other, by different amounts each time!
A single, 4-input internal capture card fixed all of that:
www.acasis.com

ACASIS PCIe Capture Card

Acasis PCIe capture card supports multiple HD resolutions (such as 4K60Hz), bringing crystal-clear visual effects to the audience. It also supports quad HDMI or SDI simultaneous input, allowing you to flexibly adjust between different camera angles or input devices. Solve your professional video...
www.acasis.com www.acasis.com
www.acasis.com

ACASIS CAPTURE CARD DRIVERS

PCIE CAPTURE CARD AC-4HDMI (Quad HDMI-1080P60).zip AC-4SDI (Quad SDI-1080P60).zip AC-4HDMI PLUS (Quad HDMI-1080P60).zip AC-4SDI PLUS (Quad SDI-1080P60).zip AC-VS2583 (2 HDMI-4K60).zip AC-VS2584 (1HDMI+1SDI-1080P60).zip AC-VS007 (Dual HDMI-1080P60).zip AC-VS014 (2HDMI+2SDI-1080P60).zip AC-VS049...
www.acasis.com www.acasis.com
Those cards are good, but the thing to watch out for in general, is that the cheap ones - often geared towards security systems - only have a single converter. It's cheaper to do that, plus a quick-and-dirty switch, than to actually have a dedicated converter for each input. This means you can't see what a different, non-live input is doing, and you can't have a nice transition between them. The cards that I linked here, DO have a converter for each input, so they DO work for video production.

If you *must* use USB, go with a name brand, and expect to spend about $100 per channel, to avoid the problems above.
 
I see this is an older post but with some recent responses I thought I would jump in. I would agree with Josh and Aaron. Find a temporary solution that won't cost a lot but will function for you, cheap is ok if it works for you.

I am finishing a PC Build specifically for Streaming live services/presentations. Since our new system in the auditorium will be an SDI based Video system (slides and cameras), I have installed the PCIe Black Magic Deck Link Duo 2 ($500). Since our presenter laptop is already being converted to an SDI video feed network, I will be able to tie it directly into the PC along with the 2 PCI cameras that are being installed. This is something to look into for those looking to grow/expand moving forward. (basically same things as Josh is doing with HDMI). As a note SDI cables are sturdier and can carry video longer distances than most VGA/HDMI systems.

My original Test system was my AMD Ryzen 7 5500 series laptop with Radeon Integrated Graphics. I had audio coming from the Mixer via USB Interface, and my cameras were 2 phones using the OBS app on each phone, and then an HDMI to USB game capture for the presenter Program. This worked well with little issue in the actual program running, had much more issue with our network.

Yes there will be some delays through the capture devices but these can be matched up within OBS. For me I ran the presentation program and the cameras and then watched each as the slides changed. I found about 500ms (.5sec) delay that had to be added with a filter for each camera to match up with the slides. I took that same time and added a delay to the audio to match things up that way as well.

1 issue (depending on the system) with NDI is the lag could change at any time, of course when live there isn't much you can do about it. The Biggest Issue with any laptop trying to run Multiple cameras/video sources via USB will be Bandwidth on the USB Header. When I tried to add a Canon DSLR direct USB, I lost my video feed from the presenter Laptop. This will be a common issue for all Laptops, they can't handle the extra bandwidth on the same header. I could run one or the other but not both.

A work around on this if you have a solid network and don't have USB available, is to add OBS to your presenter pc and single scene capture the slides, and send Via NDI. On the stream pc add it as an NDI source and you can bring the slides in that way. Again be sure to check latency.

I hope this helps some folks.

If anyone is interested in the system I am putting together for our stream computer here is some information. Feel free to ask questions on it. (est $2500)

AMD Ryzen 7 7700
32 Gig Ram
Asrock B650 Live Mixer Motherboard
Asus RTX 3060 TI video card
2- Black magic SDI Cards (1 for expansion)
1tb M.2 SSD (operating system)
4tb Sata 6 drive (data)
80 Gold 750W Power Supply

This will have 2 PTZOptix 30x SDI Cameras attached, that can be fully controlled within OBS with the Companies OBS addon.
 
Hello Everyone: I have just gone through a computer/screen sharing reconfiguration, and in case my experience is of interest, here are my comments.

Until recently we had what I assume is common in a house of worship configuration - a livestream computer (OBS), and a presentation computer (projector/display slides). Both these computers were iMacs and on the same internal network, so screen sharing was easy using the Mac Screen Sharing app. This app allows access to both the main display and the auxiliary/projector display on the presentation computer, from the OBS computer.

Then I replaced the OBS iMac computer with a Windows 11 computer, so the Mac Screen Sharing was no longer an option. Here are the alternatives that I considered:
  • NDI
  • VNC e.g. RealVNC
  • Hardware connection
NDI - I had tried NDI before with mixed results. When it worked it was OK, but I found it to have high resource usage and it would freeze frequently. Essentially it was unusable; however, the problems may have been due to the fact that the presentation iMac was old and unable to support NDI. If the situation comes up again, I would be willing to give NDI a try on a more up to date configuration.

VNC - I did not find a VNC app where I would be able to access the auxiliary/projector image on the presentation computer (still an iMac), from a Windows 11 computer. And I was also concerned with the potential for lag.

Hardware connection - in our setup, the 2 computers are next to each other, so it was a relatively simple process to split the cable (HDMI) going from the presentation computer to the projector, and connect it to an HDMI capture card plugged in to the OBS computer. This is the option I settled on and to date (only 2 events!) it has worked well.

Where I did have to do some work was to have multiple instances of the image - one filtered, one unfiltered. (The issue being keeping the filter from being applied to all references.) I tried applying the filter at a Group level, and this worked, but I am now using the Source Clone plugin to achieve that same results.

I hope this helps. . .

Cheers,
Tony N
 
Chrishanscom said:
I am finishing a PC Build specifically for Streaming live services/presentations. Since our new system in the auditorium will be an SDI based Video system (slides and cameras), I have installed the PCIe Black Magic Deck Link Duo 2 ($500).
Click to expand...
I tried that card first, beat my head against the wall with it, and had the support guy beating *his* head against the wall too, before finally giving up. Then I found the one that I linked above, and it works perfectly!

The reason the DeckLink Duo 2 doesn't work is because it's not its own product. It's a slight upgrade to an existing one that is also severely limited in functionality. It advertises as if you can use all 16 combinations of in or out across the 4 plugs, but the settings app won't let you do that. A simple combinatorics exercise on the options that it does have, gives a much lower number of possibilities, and none of them have 4 inputs.

If I remember right, the actual maximum is 2 inputs, and they pass through on the other 2 plugs as outputs...if you can even get *that* to work. We had some trouble there too, on both Linux and Windows, but every once in a while, I could play a test video on an output and get it to show up on an input through a short BNC jumper. That wasn't consistent though, even with their own apps.

They offered to send it to the factory to get it checked out, but when I did the combinatorics exercise with the available settings, I saw that it was pointless anyway. So I sent it back to Amazon instead for a full refund, and tried the Acasis one instead. Like I said, it works perfectly! 4x SDI, all input.
 
AaronD said:
I tried that card first, beat my head against the wall with it, and had the support guy beating *his* head against the wall too, before finally giving up. Then I found the one that I linked above, and it works perfectly!

The reason the DeckLink Duo 2 doesn't work is because it's not its own product. It's a slight upgrade to an existing one that is also severely limited in functionality. It advertises as if you can use all 16 combinations of in or out across the 4 plugs, but the settings app won't let you do that. A simple combinatorics exercise on the options that it does have, gives a much lower number of possibilities, and none of them have 4 inputs.

If I remember right, the actual maximum is 2 inputs, and they pass through on the other 2 plugs as outputs...if you can even get *that* to work. We had some trouble there too, on both Linux and Windows, but every once in a while, I could play a test video on an output and get it to show up on an input through a short BNC jumper. That wasn't consistent though, even with their own apps.

They offered to send it to the factory to get it checked out, but when I did the combinatorics exercise with the available settings, I saw that it was pointless anyway. So I sent it back to Amazon instead for a full refund, and tried the Acasis one instead. Like I said, it works perfectly! 4x SDI, all input.
Click to expand...
Thanks for the Info,

I bought one card, though I have not had the chance to set it up yet. The installation company for our Audio also recommended this card. So hopefully its not an issue as I will actually have 2 of these cards in my system.
 
Chrishanscom said:
Thanks for the Info,

I bought one card, though I have not had the chance to set it up yet. The installation company for our Audio also recommended this card. So hopefully its not an issue as I will actually have 2 of these cards in my system.
Click to expand...
Yeah, I don't trust "installation companies". I used to work for one in a different industry, and we never gave anyone the best possible solution. It always *worked* - we made sure of that, sometimes with late nights on site - but it was primarily designed to be a quick turnaround for us. Shove it out the door, and move on to the next customer. As long as they don't complain, we're all happy.

So it's easy for me to see the same thing in this industry too. What the customer doesn't know, leads to problems that they think are simply inherent to the physics, when in fact they're not. The cookie-cutter solution is just trying to use a hammer to drive a screw...and sometimes you're stuck with that hammer-driven screw.
 
I am still going to give it a try with the BM Duo. I have a co-worker who hasn't had those same issues with his setups. IF its to much Hassle I will switch it out.
 
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