NDI, Flame UI, refresh rates, and the hunt for the ultimate screen sharing solution

Logik Lovelies,

I am constantly needing to share my Flame screen with clients and colleagues. NDI for this has been amazing. Fire up a Mac Mini or a Tiny 340, install NDI Tools, boom, instant Virtual Webcams and NDI Studio Monitor picks up my Flame UI over the network and is instantly shareable in Discord, Google Chat, Zoom, blah blah blah. The trouble is, I also like sharing other things on my Linux box that aren’t in Flame…Mocha standalone, PFTrack, Linux itself, Mocha OFX, etc etc. Therefore, NDI output via Flame isn’t very helpful because it ain’t Flame serving as an NDI encoder.

So, I picked up one of those Bird Dog encoders to hijack my Flame UI monitor out straight from my RTX 6000 and encode and serve that as an NDI device, and can then use either NDI in Flame or SDI / BMD 4K Mini Monitor to monitor Flame broadcast monitor locally or serve NDI images via Flame.

This all works great until I try to play back clips in Flame. Disk speed isnt an issue, its 12Gb/s at the framestore. But I drop frames for any clips that don’t have audio at any resolution when I have a DisplayPort to Birddog connected because I think that the Birddog sees my monitor as 60hz/30fps which results in Flame not liking playback and drops 23.976p frames unless I add a blank audio track to it. Remember back in the days of sync generators when you tried to play back 23.976 but it wouldn’t because you had NTSC sync routed to your Flame or had a non 23.976 VTR routed to you? Well, it feels like that.

So, how do I get the best of both worlds? I would really love NDI 3840x2160 29.97/30fps of my Linux machine (basically looks like a second mirrored monitor) whilst Flame with NDI sends 3840x2160 23.976p which matches my source material.

Am I crazy? Is there an easier way? I’d ideally have something setup that I could just set it and forget it as my needs change almost daily and I’m tired of crawling under the desk and just want something setup that satisfies both needs…Flame Broadcast monitor output over NDI, and Linux/OS level output via NDI as well.

Dumb idea #612…standards convert the 60hz/29.97fps “RTX 6000 output” from HDMI to SDI to Blackmagic CrossConverter to 23.976?

Have you thought of the black magic atem mini being part of your setup?

I’ve currently got one and have the teradici output, Mac mini, laptop and canon r5 all as hdmi sources I can switch between in teams or zooms. The atem has usb c output so all the usual video chat suspects see it as a usb webcam. I also kinda like it’s hardware doing the work.

Not sure how your plumbing is, but I love this little thing. It turns any hdmi source into a webcam and I use it for client sessions, video calls and FaceTime tech support with my folks back in England. It also plays nice with various frame rates.

Might be worth a bit of research. $300 for the 4 input one I think.

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In theory you could have one input be the “broadcast output’ and one be a mirror of your UI monitor perhaps

Zoom->Share Screen? It probably won’t be as pretty as the NDI version, but it works!

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Thanks @benjidavidson, kinda forgot about that little rascal. Its such a good device Im glad I already own one! It’s a great idea, one that I would not have thought of so thank you for that. Sadly it falls flat because its expecting a 1920x1080 input, and my local monitoring is 3840x2160. I can essentially use the Atem Mini in the middle of the back of the computer and an NDI encoder, but sadly the only way I can get Centos 7 to output the entirety of a 2160p desktop into a 1080p input on the Atem Mini is to set the ViewPortIn to 3840x2160 in nvidia-settings which looks pretty shite.

@hBomb42 , I wish it were that easy as Im also trying to record and screen capture and use NDI for local 4k monitoring so Im super greedy. It’s a tall order and I’m certifiably insane.

get a HDMI splitter with dowscaling support (professionals like the aja 4k2hd or whatever that is called , or something cheap, I have some oddly reslly cheap one that works fine even with dolby vision)!.

splitter will only give your computer the metadata of screen 1 and then dowscale to 1080p for hdmi2

i use this to drive my UHD reference monitor and my 1080p projector at the same time.

Hdmi splitter then goes into birdDog and bob should be your uncle .

If you still have fps issues get a decimator those things fix all the issues ever.

here is the splitter that I use; https://amzn.to/3djOJ9P


So yeah, the HDMI splitter / Birddog combination turned out to not be effective. The Birddog (as confirmed with their support team) is expecting a smpte friendly signal and therefore was rejecting my 4k60 ui over HDMI. Using xrandr on the Centos side made it possible to output a downscaled 1080/60 signal, but let’s just say the filtering/scaling algorithm is not the best in the world.

The Atem Mini Pro was a star and basically took any input over HDMI and made it Birddog friendly. But, I really didn’t want to lean on this as it was a messy chain of splitters/downscaler then Atem Mini then Birddog. Yuck.

The real star turned out to be an Elgato Capture HD60S+. This sub $200 hdmi capture device with 4k60 pass through turned out to have a beta feature it calls Stream Link. Guess what? It’s a fecking NDI encoder as well! So, for those looking for a simple HDMI based capture device and NDI encoder all in one for under $200 that was Amazon Primed to be in less than 4 hours, the HD60S+ is hard to beat. HDMI in at 4k60, HDMI out at 4k60, with a USB 3 connection to Windows or Mac delivers solid capture and NDI encoding? That’s hard to beat.