NDI output on Mac is very laggy and drops lots of frames

The NDI output from Proclaim on our Mac is very laggy, dropping frames and really unusable. The lag seems to be variable as well which doesn’t help our operators when they are trying to time the lower thirds that go out with our livestream.

We’re transmitting low bandwidth NDI at 30Hz, higher band or 60Hz is even worse.

If I run an NDI output from Proclaim on a PC it works fine. So I think there’s a Problem with your Mac NDI code.

We're running a 2019 iMac 3.2GHz 6 core, 16GB, Radeon Pro 560x 4GB graphics card. We run 3 physical displays from it (built in, slides and confidence), and then try and run the lower thirds of NDI where we are having problems. The Mac itself doesn't seem to be overloaded when taking a look at Activity Monitor. The Mac is plugged into the same Network switch as the Streaming PC with VMix that takes in our NDI signals (4 P200 camera feeds plus NDI from Proclaim). The network on the Streaming PC is not overwhelmed to cause drops there. I can only think it's Proclaim generating a bad NDI signal.

Please help, this has been happening for too long

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Michael Wright

I’ve reported this issue several times over the past few years and am still waiting for a fix from the developers. My work around is to output your live feed overlays, with the green screen, to an additional monitor. Then pickup that monitor output using OBS and turn on the green filter for your camera input. Seems to work quite well.

Andy Bleach

https://community.logos.com/discussion/comment/1236958#Comment_1236958

Thanks for this Michael. I'm glad I'm not the only one seeing this. Yes I might need to look at an alternative as you suggest - I just liked the fact that the built in NDI contained transparency already in the signal so you didn't need to green filter (chroma key) and then have to worry about what people are wearing etc.

I like it that Proclaim added NDI in, and issues like this were OK at first, but now I believe they do need to be addressed. Proclaim support can you comment on this?

Jordan Sjodin

First off, sorry to hear this. I was (and am!) personally very excited about NDI as it feels very 'modern' compared to chroma keys and even key/fill with Luma keys, as like you mention, the transparency is built in!

Then it is just super natural and easy in Proclaim. Any transparency is preserved, any gradients or partial-transparency work. Super cool!

In our own testing, it has seemed pretty good.... We even bumped it up to 60hz as you mentioned and still get good quality. For me, this was mostly done on a MacBook Pro (15 inch, dedicated graphics, 32GB RAM).

We have had some reports of issues, but NDI is more susceptible to issues too. (Lots of times people with issues are on a non-dedicated WIFI network, so your results may very.)

Odd though that you say you are hard wired... So it does make me think something might be up with our Mac code.

The same capture code that underlies NDI is what we use for our BlackMagic SDI/thunderbolt integration too. My church uses this each week (One Decklink Duo 2 with key/fill slides for transparency, confidence, and our center screen) and it keeps up with all of it. (and it is also a similar iMac.) However, in that previous case, the data is transferred via thunderbolt to an additional device for processing, where as the NDI is still handled on the host-machine.

If you have time, could you try a few tests using NewTek's Video Monitor? It comes with the Tools here: https://www.newtek.com/ndi/applications/

That app is straight from the folks that make NDI, so if you see lagging there too, that would show its probably from Proclaim. Also, it should allow you to record it so we can see what you mean first hand.

Andy Bleach

https://community.logos.com/discussion/comment/1237017#Comment_1237017

Hi Jordan, thanks for replying. Sorry it's taken me a couple of days till I can do any testing. OK so I think I've found the link is something to do with the network between the Mac and the streaming PC.

I did what you suggested and tried running Newtek's Video Monitor. If I run this on the same Mac that the Proclaim NDI signal is on there is no lag, which to me would seem to indicate that Proclaim is generating NDI OK. When I run Newtek Studio Monitor on the Streaming PC it is delayed and dropping frames (say on the Bible trivia countdown). If I try and send the video output from Proclaim using Newtek NDI Scan converter, this also causes delay and dropped frames on the streaming PC. So I'm not sure what the issue is between the Mac and PC in terms of network. They are both plugged into the same network switch which handles our NDI traffic and is not overloaded.

Any ideas welcome.

Jordan Sjodin

https://community.logos.com/discussion/comment/1237561#Comment_1237561

Do you have other NDI running through that switch too? (Like cameras)

My thought is the ethernet cable a cat 5 or cat-6? I don't know a lot about ethernet but I do know the way they wrap and shield the internal cables affects quality/performance.

Additionally, is your switch a Gigabit ethernet switch? Perhaps its hitting a bandwidth limit.

How far apart are these two computers?

Andy Bleach

https://community.logos.com/discussion/comment/1238622#Comment_1238622

Hi Jordan, thanks for your thoughts on this. I found the issue! The Mac had wifi turned on as well as using a wired Ethernet cable. And guess what, turning the wifi off fixed the lagging! It seems the Mac favoured sending the Proclaim NDI over wifi rather than Ethernet.

I'm not a Mac person, but I would have thought data sent / received would favour the ethernet connection not wifi. Maybe that's something to look into, in case for Proclaim you can force the NDI to go through an ethernet connection rather than wifi if both connections exist?

Anyway, hopefully this might help for others who have NDI problems - ask them if they have wifi enabled

Andy Bleach

https://community.logos.com/discussion/comment/1236958#Comment_1236958

See my fix below - I turned wifi off to force the Mac to use the ethernet connection and the Proclaim NDI is now all happy again

Hispanic Ministry

https://community.logos.com/discussion/comment/1237017#Comment_1237017

Hey Jordan, quick question about NDI. I recently stumbled upon NDI and OBS and I don’t really know how it works. Anyways, I created the Lower Thirds NDI in Proclaim. I’m on a Mac by the way. Anyways, I want to know if I can send the NDI from the Mac running proclaim to another Mac running OBS. I haven’t tested it out yet, but I wanted to see if anyone had and how they did it.