Output to BlackMagic Web Presenter with SDI input?

mlowery

New Member
I have one of the newer BlackMagic Web Presenter 4k boxes, and was going to offload the actual encoding work to that box which can easily handle it, but I am unsure of the best way to get that accomplished.

I can output the clean 'production' via 'projector', but without an actual second screen plugged in (and I even tried some HDMI EDID Emulator plugs), but the projector only sees my single screen as an output option.

In windows, even with the dummy plug, and windows showing a second monitor, I can't choose the second output in OBS, only screen 1 shows up.

Is there another way to send the clean feed out of the HDMI port so I can get it off the PC to the Web Presenter for encoding/streaming?

And if it is the only way, anyone been able to get the HDMI passthrough Dummy plugs to work in some way in OBS?

Thanks for any help.
 
more informations over the PC its an Laptop or PC ? did you try use the onboard ouput and have the main screen on a Dedicated Card ?

obs log please !
 
I am not sure about the log, don't think it will show anything... but I will look into that tomorrow. Is there simple instructions on how to capture the log? this is the first time I have come here with a question...

It is an Intel NUC Hades Canyon i7, so no add on cards or anything like that. Has tons of ports an lots of monitor options, but unless I hook up a monitor, there is nothing to send it to.

I did have a thought over the weekend to try the 'extend desktop' option to the second monitor detected in windows by the dummy plug, but haven't tried it yet.
 
It was in fact the 'extend display' that allowed me to use it correctly.

Once the desktop was extended there, then it shows up as an option in projector output.

There is also a selection in the configuration to hide the cursor from projected output in case you stray into the extended screen area.
 
I am thinking about doing the same thing. I am using a PC (Lenovo Laptop purchased for something other than live streaming) without a dedicated graphics card and am experiencing high CPU usage and encoding frame drops.

The vast majority of content I have seen on the Web Presenter 4K has the setup in the reverse of what I would like to do and what I think your intent was - i.e., video sources plugged into the Web Presenter sparce number of inputs (like a tiny camera switcher) and then routing to OBS for encoding and streaming. I would like to mix my stream, both video (digital, mainly NDI) and audio (digital, through a Focusrite audio adapter) and send that content from OBS to the Web Presenter to be encoded and streamed off (via YouTube).

It sounds like you have made that work using an extended desktop. Doing it that way, do you send the extended desktop to the Web Presenter using Virtual Camera, or do you set it up in the output tab of settings? Are you connecting OBS to the Web Presenter using the SDI input or the one of the USB inputs?
 
It sounds like you have made that work using an extended desktop. Doing it that way, do you send the extended desktop to the Web Presenter using Virtual Camera, or do you set it up in the output tab of settings? Are you connecting OBS to the Web Presenter using the SDI input or the one of the USB inputs?

So I bought these, and they made it work.


Using that as a passthrough, the computer thinks that is the second monitor, and you can just do the presentation output to the second screen, which sends that clean signal out that HDMI without the need to actually hook up a monitor.

You need to set that second monitor to extend desktop.

I then used a Blackmagic HDMI to SDI converter box, which allowed me to pass that signal into the SDI input for the Web Presenter.


so just with the one laptop, you can still produce and use the OBS interface, while sending a clean output signal to the web presenter to connect and encode.

Even a 4k 60p output on my laptop only runs 10% on the CPU now.

Hope that helps
 
That sounds fantastic and is exactly what I had hoped the Web Presenter would be able to provide.

Are you running your audio separately via the XLR or bringing it in digitally via the HDMI/SDI? In my case, the audio is converted from analog to digital by the Focusrite so audio encoding does not create stress for the PC.

Thank you for your quick and on point response.

Brian
 
I am sending (live streamed church services) to YouTube with a 4K ptz (Canon CR-N300) so a max desktop of 4K. I would like to transmit to YouTube at 1080 at 29.97 FPS. What do you have the resolution and frequency of your emulator set at and what is your output resolution and frame rate?

Thanks,

Brian
 
I am bringing audio into the camera and bringing it embedded with the video together.

Then just use that main audio input as the audio even when we switch to other cameras.

We used to use the older web presenter to bring in audio via XLR, but since they removed that port, and added the encoding capabilities, it sort of allowed me to re-work the entire setup to use it best (I didn't even know the web presenters now included encoding, just needed them for the webcam input of the nice cameras to OBS).

Although I have set up everything to make sure it works at 4k and what the load is, we don't stream that high.. only 1080p 60fps for us.
 
I used the Web Presenter for the first time today. Worked really well from a bandwidth and computer processor load standpoint.

However, on my streaming laptop, when I have OBS running, anytime my cursor passes over the OBS icon in the taskbar, either to switch back to OBS from another application or accidentally, the full screen projection feed flashes to the desktop that would be behind the extended desktop. No icons or taskbar, but definitely not my clean OBS feed. Did this happen with you? Did you figure out how to prevent it?

Brian
 
I just realized last night that my audio feed to the Web Presenter was just my monitor feed, so none of my filters and setting delay is pointless. You mentioned above that you route your audio through a camera's audio input. I am using an audio interface (Focusrite Scarlett 18i20), fulfilling roughly the same purpose. I am able to get all of my inputs into OBS, but can't get the sum out to the Web Presenter unless I have all sources set to output and monitor and the monitor device set as the Web Presenter.

Do you have your camera set as a global audio device such as desktop audio or mic/aux in audio settings?

Brian
 
I am bringing audio into the camera and bringing it embedded with the video together.

Then just use that main audio input as the audio even when we switch to other cameras.

We used to use the older web presenter to bring in audio via XLR, but since they removed that port, and added the encoding capabilities, it sort of allowed me to re-work the entire setup to use it best (I didn't even know the web presenters now included encoding, just needed them for the webcam input of the nice cameras to OBS).

Although I have set up everything to make sure it works at 4k and what the load is, we don't stream that high.. only 1080p 60fps for us.
Hey MLowery!

When you stream with OBS and the Blackmagic Web Presenter 4K, are you using the Streaming, Recording, or Virtual Camera functions of OBS or just pressing On Air on the Web Presenter?

My problem lately is sound. I am getting the picture in great, but the OBS sound filters and sync delays only apply to the tracks that are recorded or streamed by OBS. Since I have appreciable video latency 2-300ms, I would like to be able to add sync delay to the audio that goes through my HDMI to SDI to the web presenter. I can’t get that with the monitor feed, which is pre effects.
 
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