I'm working with a 4k version of vmix, and I am unsure if what I want to do should be achievable or not.

I have a few different inputs, and I would like to use the Instant Replay feature, while also doing multicorder on all the inputs I have, so I have "raw" versions of the sources for post-prod fun stuff (promo videos later on).

I can't quite figure out how though to get Instant Replay and Multicorder running at the same time. Is this a limit of the license, or am I doing it wrong, or what? I hope I'm doing it wrong, because I really want to have my cake and eat it too!

Please advise :)

The Instant Replay for 4k is only one input, but I want to record 2-4 inputs to raw video for later production (not live replays), hence the mismatch and such. I want to figure out a way to do multicording of as many inputs as I can, agnostic of however many Instant Replay sources I am licensed for. Not trying to cheat here, just doing two similar, but different tasks, at the same time.

Well that seems really lame, having to choose between Instant Replay or Multicorder. Especially when there's enough resources to go around. I actually need both!

What does one do when they need both?

I've used a variety of network IP video senders in the past. I haven't fully explored NDI but I am really sceptical of the fidelity compared to original raw. Is this really the _ONLY_ way to do this? Or the only way that you are aware of? :/

To add some detail, I do system architecture regularly, so storage performance is part of my regular work.

147megabits converts to a little over 18megaBytes, which is very easily achievable on modern drives. But let's assume for a second that I could do multicording and Instant Replay on the same system for a second. Our inputs are about 20mbit/s for video fidelity, which actually turns into 2.5megaBytes/s for each input as sequential writes to disk.

Modern spinning disks (2-4TB and higher) can write at speeds starting at about 100megaBytes per second, and really good spinning disk HDDs can exceed 150megaBytes/s write speed.

Good SSDs can write at speeds of upwards of 500megaBytes/s, and that's just SATA SSDs. NVMe SSDs can go beyond 2,000megaBytes/s depending on which you get.

So, not only on paper, but in practice that we've seen, the situation is most definitely not a hard drive bandwidth issue. Now, when I say that, I'm talking about multicorder, not instant replay, since I know that's a completely different beast.

That being said, perhaps I should revisit the NDI element of this. The statement of "Lossless" seems rather unbelievable, as that is an absolute statement, but I'll have to see what it's really like.

In such a configuration though, wouldn't I need to buy two licenses of vMix then? :/

Also, our spec is 1080p60, 30 isn't enough FPS for us, as we deal with high-motion content ;P

I don't know where you're getting your info, but video devices rate data signal in megabits, not megabytes. It even says in vmix for the inputs I use that I'm getting a bitrate of 20mbits, not bytes.

1080p content, whether it's 30fps or 60fps, doesn't actually need as much speed as NVMe can do. So "regular" SATA SSDs can do the trick really well. Record to SSD, later move to spinning disk, bob's your uncle.

Should one need more NVMe devices, for whatever reason, you can get PCIe devices that add more.

I haven't looked at the NDI options just yet, probably won't be able to for a while. But the input devices we use currently we limit them to 20mbps, so available space is plenty at this time. It certainly is an important facet! But that's not the current hurdle. :)

Don't worry though, at least I know you're human now ;)

@BloodyIron - Not sure if you were still after an answer on this...

The Option of NDI will work with a second dedicated box recording the NDI Output>Inputs - That said I have found the use of NDI does indeed increase CPU usage even on the VMix box as it sends. But at least you don't have to worry about latency since you aren't using the NDI box for anything other than External capturing - Limitation to this method is you can only really add 4 or so NDI outputs

Something else to consider instead though - I had wanted to do the same thing as yourself, Record Cam1, Cam2, Output have replays and also have a need for the Raw footage afterwards. To get around it (hopefully all you want is up to 4 Cameras...) - is to use the Replay feature itself. Replays are held as Complete streams Per Camera (up to 4) - the Replay function just works like an EVS, it doesn't cut the footage (until you export it.) - it is just XML files with timecodes. That way what you do at the end of Production is grab the "Replay" folder which will contain a whole lot of "Camera 1 - Date and time.mp4" files of around 11Gb each and "Camera 2 - date and time.mp4" files - all of which you can now import into your NLE and they are seamless end to end. Then the only thing hampering you is Storage speed (High end SSD suggested.) - and also capacity as well as the Bit rate you record them at within the Replay Control section.