more than 4 video inputs? (redux)

thatmattrogers

I know that this has come up before but it it was a VERY old thread so I thought I'd just start again.

Isadora has a hard limit on video inputs. so I can only capture streams from 4 cameras at a time.

that seems fine. I don't have unlimited USB ports and things tend to go wrong whenever I've tried using a hub for video.

the only way I can see to extend that number is to have one of the inputs actually be an output from a second computer running another instance of Isadora which in turn has 4 cameras being input into it.

in my head that second computer has a simple patch which allows me to select any of the video streams that I want using a simple osc command. it would introduce a little bit of extra lag but it's definitely workable.

the only problem I see is if I want to use all 7 camera feeds at the same time meaning it might end up being a bit of a headache.

is there a more streamlined way to go about this... or is this basically THE WAY to work with lots of cameras?

Juriaan

@thatmattrogers

Hi there!

It depends a lot on your OS. You are right that Isadora right now can only handle 4 Live inputs at the same time. This is basically because back in the day when we released this feature computers were not as powerful as they are now. 16Gb of RAM for example was something that was not as common.

Anyhow, it will take a while before we lift this. If you could share some details we might be able to give you a temporary workaround that doesn't require a second machine.

Let us know :)

thatmattrogers

@juriaan

Hi,

on this project the main production machine runs windows. It's not the most powerful machine you'll ever come across; its got 16gb of Ram and is running an AMD 5900HX 8core APU.

The tricky thing about this one is that its a research project playing with live video production and simultaneous live performance and streaming; so as I'm building the initial setup I'm trying to work in as much flexibility as I can in terms of available camera angles, there's also been a suggestion of using a kinect so that's a hole other video feed as well.

In terms of available USB ports; I've got 6 without having 2 video inputs sharing the same bus, so the limits would be 5 capture cards and a kinect.

of course things get a little easier if we don't end up needing to use a feed from every single camera at once, because i can just use a usb video switcher like an ATEM mini or something; but at this stage, like I said, it's all about creating maximum flexibility so there's as little friction between ideas and the tech as possible.

Fred

@thatmattrogers You have some options, if you are using HD inputs you can use a 4k capture device and a 4k quad splitter (watchout for latency it varies betwen devices) with 4 HD inputs. You then need to crop each input to treat them individually. You can also use another computer and send the signal via NDI over the network. Or you can capture internally and use something like blacksyphon (there is a spout eqiuvalent) to send extra video streams to Isadora.

Just a note, live video capture is a computationally expensive task, difference capture systems have different overheads, some cheap USB capture cards have a higher overhead as they send compresed streams that need to be decompressed (generally on the CPU) before they can be used. Blackmagic and other higher end capture cards often have less overhead, but either way 7 live inputs is a heavy task just to get the data from the capture device and on the GPU where Isadora can do something with it.

thatmattrogers

@fred I'm a complete novice at this so bare with me.

I've never used NDI so I'm coming in a bit blind, but from a cursory reading it could easily handle 4 video streams over a network. which seems great.

the thing I can't quite get my head around is 2 things:

1: how does isadora interface with NDI, is it though a video in type watcher? I don't know.

2: would it be possible to pre process the video into a friendlier codec on one machine before sending it to a second in order to reduce the overhead on the production machine? obviously that would increase lag... but it is it even theoretically possible?

Fred

@thatmattrogers

1.There is an NDI watcher, again this is CPU decoded so there is a reasonable overhead.

2. Generally no, the overhead comes from the capture process, what capture card are you using? If you were using some cheap capture dongle that sends a compressed H264 stream you ***may get less overhead on one machine by sending NDI from a second, but at that point it would be a far from optimal setup and getting a proper capture device would be advisable. There are blackmagic cards that have 4 adn 8 inputs, AJA cards that have similar, Bluefish cards that also have multiple inputs.

To do 7 HD inputs I would be looking at a threadripper machine and a beefy GPU like the 3080.

mark_m

Am bumping this subject up as I'm about to start R&D on a show which - ideally - would have a large number of video inputs.

Obviously computer technology continues to evolve and improve, and just wondering if on the future Isadora roadmap there are plans for more video inputs?

Of course NDI becomes an increasingly viable method of getting video into Isadora, with more and more NDI enabled cameras on the market, as well as things like Obsbot's UVC to NDI adapter, and some Atomos recorders also being NDI equipped, it looks like a good way forward.

Anyone know how Isadora processes NDI? Is it on the CPU? GPU? I wonder what the max number of streams is... anyone tried it?

Woland

@mark_m said:

Anyone know how Isadora processes NDI? Is it on the CPU? GPU? I wonder what the max number of streams is

We don't put any artificial limitation on the number of NDI Watcher actors you can use at the same time as far as I'm aware.
We can't and don't control how many NDI sources are visible from other software on your computer or from any networks to which you're connected. (Though I've never had more than ~10 going, so it's possible that when you hit silly numbers like 50, 100, 200, etc you may run into a UI issue where the full list won't fit on the screen. In cases like this you could still use the List Selector Control with an Edit Text Control to create a searchable list of NDI sources [example file & video tutorial].)
Really the only limitation is down to how many NDI streams your production computer can handle. As always, the safest thing is to bench test in near-show conditions as soon and as much as you can.

Armando

@woland @fred Thanks for you inputs as always. I have another technique and I found that through different interfaces I have a mich higher number of video inputs. I have a blackmagic ATEM extreme HDMI. They can have 8 HDMI cameras and since via usbc they arerecognized as a webcam I can have 8 1080 cameras (not at the same time of course. But I use them sometimes with 2 intsta 360 lnk usbc. In the end It is pretty much the same but I can have 8 cameras (one at the time via the ATEM) plus 3 others (can be iPhone and 2 360 links etc. I never used all of this PLUS NDI but It makes a lot of cameras possible. Please note that the ATEM can be controlled via OSC so I can have 4 non NDI cameras actively digitized but I can chose from 11.

The only limitation of the system would be removed if we could have all the parameters of the live capture settings as an actor (Channel enable, select, driver, device resolution, sound input, device and audio gain as part of a hypothetical"Capture control++" actor. In this way we could have a bigger choice made possible from within the patch more or less on the fly from within the patch, and not in the live capture settings window that need to be manually operated by a hands-on thechnician... Would be this a crazy feat request? (if not including NDI an syphon/spout sources too maybe ?). Even if Isadora couldn't handle more than 4 cameras at the time all the cameras switches could be done interactively during the show by sensors.... just dreaming.

Since I also have a blackmagic card in a sonet usbc cabinet that can take 4 more 4k hdmi cameras the possibilities of such an actor could expand le number of connected cameras to chose from within the patch too...

Just a thought

mark_m

Thank you.

To be clear, it's not more than four *inputs* that I'm looking for, it's being able to show more than four live video streams on a stage at once.

I echo @Armando' s endorsement of the ATEM switcher. I use an ATEM MIni Pro, automating its inputs via OSC and Banyan AV Bridge (formerly ATEMOSC). The ATEM Mini is great at regulating different sources into a unified output (USB C) which is seen as a webcam in Isadora. I found it was the only solution for combining GoPro HDMI feed (notoriously not meeting HDMI standards) with other HDMI sources.
The ATEM mini series are also great in that you can use them with a computer that doesn't have Thunderbolt, which is necessary for capture devices like the Blackmagic Ultrastudio 3G.

I also use an ATEM TV Studio HD when I need to get an image from an SDI source, or combinations of HDMI and SDI sources. Have to use a Blackmagic Ultrastudio 3G to capture the video into the computer and Isadora. But this I can also control with OSC.

I have also used Kramer matrix switchers in conjunction with Blackmagic Ultrastudio 3G to capture the video into the computer and Isadora. The input (and output) of these Kramer switchers can be controlled VIA TCP/IP commands, so can be automated in Isadora. Kramer have a downloadable software (Protocol 2000 Calculator) that makes it easy to get the correct values for Isadora's TCP Send Data actor. The older HDMI matrix switchers can be picked up secondhand on eBay for next to nothing.

But while these devices let me choose from many different sources, they still don't let me *show* more than four lives sources at a time via Isadora's Live Capture.

Woland

@mark_m said:

more than four lives sources at a time via Isadora's Live Capture

This is not in active development but is currently one of our highest-priority feature requests

mark_m

@woland

Great, thank you: that info really helps me plan ahead. NDI adventures, here we come :-)

DusX

@mark_m

Another possible option would be to capture input from a quad. 4k input made up of 4 x HD feeds, that you chop into individual streams. I know boxes that combine feeds like this aren't very expensive, so it might be an option alongside NDI in the short term.

Fred

@dusx just a catch in this - to use 4 hd inputs from a quad hd 4K input all the Sdi signals need to be in sync with a video reference signal. Cameras or video output devices that have a video ref input are usually pro level and quite expensive.