Last I checked, Windows 11 was not recommended by vMix. Has that changed? Has the vMix officially green lit using Windows 11? I understand people may use Windows 11 currently, but I was hoping for them to officially endorse it. If it hasnt been endorsed yet, can anyone point me to a source, either a Fun Time Live Show or other where they explain why?

Thanks in advance

Still no update about Windows 11 being supported? There is a post on the Birddog User Group about Windows 10 having bug from an algorithm dealing with congested networks affecting NDI on 10Gb workflows. Apparently Windows 11 22H2 has specific features to fix the bug and also manage 10Gb connectivity better. Birddog confirmed the issue and also confirmed it is fixed in Windows 11 22H2.

This would seem to advance the urgency of getting Windows 11 support for vMix.


Here is the text and response from Birddog about this issue:



*** NDI and 10Gb Workflows on Windows ***

TL;DR If you don't want to read too much, and you are having issues with any WINDOWS workflow with 10GB, just update to Windows 11 22H2.

****
I've been working most of the weekend to drill into why we see so many issues with 10Gb NDI and Windows Machines.

It started when Dan Miall posted an update about the QUAD. How strange there was an issue with 10GB I thought? 1GB works fine? He went on to say in the comments that OSs such as Linux and MacOS don't appear to have this issue. Further, you may recall me posting here some weeks back pulling my hair out over a frame drop issue using a Flex 4K Out. I was able to reproduce it regardless of what brand Decoder I used. Instead, I stick a Mini on an HDMI output to do the decoding and moved on... Anyway, when Dan posted the QUAD update, there was something clearly broken - and it wasn't the Birddog Products, and it wasn't my network (reproduced with UBNT *AND* M4250s).

Beginning at least with Windows 10, Microsoft introduced a new algorithm [1] for dealing with congested networks. Its important to understand that even if you have sufficient bandwidth, there may be congestion elsewhere in the system (network buffers, switches etc). So NDI places a strong load on the network. This algorithm though contains a bug that under heavy load creates massive TCP retry storms. The retry storms compound on each other and ultimately lead to hugely degraded network performance, and manifest as dropped or stuttering frames.

The pattern during times of TCP connections that stall (while perhaps under high load to longer latency) look like this:

TCP spurious retransmission (SPUR) --> DUP ACK --> SPUR --> DUP ACK --> SPUR --> DUP ACK --> ............... --> RST

This pattern can be easily reproduced with NDI easily, or in fact *any other* network load causing high congestion. My testing involves artificially lowering the TCP buffers and other parameters [2] on Windows to expose this bug faster and more quickly.

Perhaps the best write up on this I've seen, in more detail is posted at [3] however this writeup doesn't discuss NDI at all, instead perhaps more correctly discussing it at a generic level.

Whats perhaps most amazing is that this issue has been posted about in NewTek Forums [4] most generically, however the common denominator is Windows.

Another note here is that this failure or bug isn't detectable normally. From the switch perspective, this is just TCP doing its thing (retrying under load), and from the host side, its just business as usual. NDI is a unique workload that exposes this bug visually.

Microsoft believes this issues had been corrected in previous releases however, there were remaining other issues. Not until the Windows 11 22H2 updated from October 2022, does it appear this issue been demonstrably fixed. There is a Windows 10 22H2 Update, though I've not been able to see if its been fixed there personally.

Its important to acknowledge my conversation with Dan Miall in all of this. This is gnarly and hard. They clearly have a world class engineering team, so despite that I'm posting this, the credit should at minimum be shared with the great

[1] https://techcommunity.microsoft.com/t5/networking-blog/algorithmic-improvements-boost-tcp-performance-on-the-internet/ba-p/2347061

[2] https://learn.microsoft.com/en-us/windows-server/networking/technologies/network-subsystem/net-sub-performance-tuning-nics

[3] http://gary-nebbett.blogspot.com/2022/01/windows-11-tcpip-congestion-control.html

[4] https://forums.newtek.com/threads/help-1-process-only-receive-4-or-5-2160p50-streams-smoothly-at-most-and-the-network-environment-is-10gpbs.166848/

[5] https://forums.newtek.com/threads/ndi-and-10g.165762/

-----OK We have done quite a bit of testing here at BirdDog HQ over the weekend as well as today and we have seen a major improvement in the Windows output when updating to Windows 11 22H2. We have been able to receive 4 x 4K60 video streams from vMix over 10Gb from this machine to QUAD in Decode mode. We can also use this machine as NDI Bridge to receive NDI from other sources and 'reflect' them (no transcode) to QUAD successfully receiving them (Think TriCaster which might not be able to be updated immediately).

Please see below a screenshot from my machine showing the update that resolves this issue.

We will be releasing a follow-up firmware this week that gives field order selection for interlaced workflows, at this point there should be a workable solution for nearly all workflows.

Once again a massive shout out to Josh Bernstein and the amazing engineering team here at BirdDog for their continued work on this.

Hi,

To clarify, vMix does not require any changes or updates to support Windows 11.
We are just naturally cautious of recommending it due to the large number of issues that 11 has had over the months since its release.
(all issues unrelated to vMix, but can impact certain features such as audio devices that in turn are used by vMix)

So to be "approved" does not mean a special new vMix release, and feel free to run vMix on it but just be sure to thoroughly test every feature you plan to use first.

Regards,

Martin
vMix

I confirmed this issue was directly related to Windows 11 22H2. I rolled back the feature update and the NDI input is working fine.

I can only second Martin here: There are a few things that might cause issues in Win 11 that have nothing to do with vMix but are blamed on it because that is where it shows up:

- Audio drivers, especially if several different audio interfaces with different vendor-specific drivers are used
- Drivers for video hardware
- NDI versions and Windows network stack
- Some mainboards with some BIOS versions that are too old / too now /not updated yet.

For instance, personally I struggle with audio clicks on a certain system with a certain USB host controller (Win 10). Such things take ages to debug...

Since newer systems (especially laptops) come often with Win 11 preloaded, we can only take the time and test things one after the other.

If working with NDI, pay especially attention to your network setup - drivers up to date, maybe BIOS up to date, NDI-Version up to date? Also look out for energy saving features in the system and on network hardware, these can get in the way as well.

@Marie03: Do you have some more details on the issues your friend has on Win 11?

Happy testing!

Christian

We appreciate very much that Vmix is making outstanding software that no one else is making. We are very sorry to hear about all of the problems with W11/12 and NDI, etc. We are hoping and praying that you get them solved. Vmix is the best video capture software we know of.

Hey AudioGreg, thank you very much for sharing your experiences. I am glad to hear you are having good success with it, even with NDI. That is very helpful.

Our (dedicated) recordingPC is an Asus ROG Hero 13 with an 11th Gen Core-i7 11700K and 64GB RAM, an AVerMedia 4k capture card, and a FocusRite 2i2. We always get the best stable name-brand parts we can find at the time.
It is a dedicated machine. Occasionally I open email or a browser to check something real quick, but 99+% of the time it is only Vmix.
We want to bring in NDI in the future (interviews, mobile correspondents, etc.) but we are not there yet.

We always do a clean format, and load only the necessary software for a dedicated machine.
We would never (ever) do an "over the top" upgrade. For production gear we want everything rock stable.

Since you are having success, do you perhaps have a guess as to what causes the problem for other people? Is it people who do "over the top" upgrades?
Or is it non-mainstream parts?

My thought is to do wait until maybe 6 weeks before the cut off W10 support, and then flip the UEFI switch in the BIOS, reformat, and do a clean install of Vmix. That it gives us enough time to get parts if anything goes wrong. (We are in Colombia and some other countries, and it takes 2-3 weeks to get parts from Amazon.)
If we knew what causes the problems for most people who have Vmix on W11 it would go a long way to easing and calming our minds.

We see MS taking away control and automating everything with AI. Of course some things are much improved, but I do not like having to fight with Windows 11 for an hour just to get control of my printer (to get it to print the way I need it to print). So we are very pensive about W11 (and W12).
Are people having trouble because of "over the top" upgrades? Or non-mainstream third-party gear? Or is there a consensus as to what exactly is causing the issues for most people? Because we would like to stay with Vmix if possible.

Yes, thank you, AudioGreg. We are planning to do all of that six weeks ahead of time. If everything looks good, the plan is a clean reformat and clean install of W11 and then Vmix and not much else.
We also treat it like an appliance.
You were right about Copilot re-installing itself. I uninstalled it before, but I checked, and it had already reinstalled itself (this is my daily driver).
We uninstall any program we do not expect to use.
If we have any problems, six weeks should give us time to go back to W10 temporarily while we troubleshoot orobtain other hardware.
Since we are not to NDI yet, we do not expect any problems at this time. Still, I am sure everyone on this forum knows how useful Vmix is, and we want to make sure we do not lose it. And that we can incorporate NDI when it is time.
I am pretty sure everything is 100% Windows certified. If it does not work with a clean install of W11 we will get something that does.
We are praying for the best, because we prefer Windows, and Vmix. It seems the ideal combination.
We look forward to Snapdragon X+ processors that can run Vmix on a mobile laptop with low power consumption.

Sorry if any of the answers to my questions might seem obvious to anyone else. I am not really a tech, but rather the alleged "talent" and the decision maker, and I am trying to find out our prospects of being able to stay on Vmix long term. If not then we need to research Apple, to have a plan just in case. But we would prefer to stay with Vmix, because the quality is better.
I am just trying to get a heads-up picture of the long-term prospects before the deadline, if that makes sense.