Blackmagic Decklink and Apple Silicon

permyth

I've seen some posts related to similar gear but they are now outdated .

for a permanent (2months) installation we need to output x4 4k60fps signals from a MacBook Pro M2 Max or Mac Studio M1 Ultra with Isadora.

were considering on using the BlackMagic Decklink 8k Pro card enclosed on a Sonnet Echo chassis.

we don't have direct access to this configuration for borrowing or rental here in Portugal and the company that sells it here has a no-return policy.

On paper it sounds that this setup can work for the purpose we need, but I was wondering if someone around here has any recent experience with a similar setup. we need to be more sure before making this sort of investment.

Im wondering how reliable it is and what might be the issues we find in the way to make it work.

thanks a lot

DillTheKraut

@permyth said:

On paper it sounds that this setup can work for the purpose we need

Well I guess, my calculations and the fine print for the Decklink 8K Pro says otherwise:

"8. These are PCIe 3 x8 cards, and they may not achieve maximum bandwith or number of video channels over Thunderbolt 3, which provides PCIe 3 x4.For example, a card that captures four 4k@60Hz channels may capture only two channels in a Thunderbolt chassis; or possibly four channels but at only @30Hz"

The lowest bandwidth for uncompressed 4k60 with 4:2:0 8bit, is ≈9 Gbps. The Sonnet Echo IIIe offers PCI 3.0 4x over TB3. Which on the cover says 40Gbps. BUT these are gross numbers. The net bandwidth won't exceed ≈32 Gbps, which is a generous calculation already.

DillTheKraut

@dillthekraut

Your best bet would be an external GPU Box, like AORUS RTX 3080 (just a quick google pick).

Sonnet eGFX even promisses to support up to 6x 4k60 with some GPUs. https://sonnettech.com/product...

Woland

@permyth

Questions:

Do all four outputs need to be individually addressable, or do they all display the same video content at the same time?
1. If it's just the same thing in four places, you can just use a 1-to-4 4k 60fps HDMI splitter to send the same signal to four displays, which is very easy, simple, and reliable. This also would mean that whatever computer you choose would only need to be able to output a single stream of 4k video at 60fps, which means a single M-series Mac Mini (cheaper than a MacBook Pro and Mac Studio) and a 1-to-4 4k 60fps HDMI splitter (a few hundred USD, probably less than $400-$500 USD) could probably handle it.
Do all the outputs need to be in perfect sync?
1. E.g., are they all edge-blended together or does a visual element travel in a sequence across all the displays in such a way that it would be bad if they were slightly out of synch, e.g. imagine a video with alpha of a cyclist biking left to right across all four displays arranged horizontally like: [1][2][3][4].
2. If not and you just need 4x 4k 60fps outputs, you could just split the outputs between two M1/M2 Mac Minis (each dealing with two of the outputs) and then network them together with an OSC heartbeat restarting the Movie Player actors/controlling cueing to make sure they can't drift out of synch over a long period of time. (This method won't get you a frame-perfect synch, but it will guarantee that they never get more than a few frames out of synch.)
In general can you describe the installation in greater detail so that we can get a better ideal of what ideas would and would not work as solutions for you? Examples of the kind of details that are helpful:

Is there live feed video involved?
Are there sensors involved?
Is it interactive in some other way?
Are the displays all on one wall of one room, are they spread out on multiple walls of a single room, or are they spread out between multiple rooms?
What are the displays that you are using?
1. If, for example, they're not actually capable of 4k 60fps, then there's no reason to work with 4k 60fps media and the hardware end of things becomes much simpler and cheaper. (This is probably something you've already considered, but I'm including it just for the sake of other users on the forum who might find this topic later who may not have your level of experience.)

If you don't absolutely have to use a Mac for this, consider getting a Windows computer with a single, powerful graphics card. You'll likely be able to spend less to buy or build a Windows machine that can handle outputting 4x 4k 60fps out of the box without having to use bunch of adapters and external hardware. Fewer pieces of hardware in the entire system means fewer potential points of failure and fewer chances to have hardware incompatibility issues. Especially since, while sometimes they do work, Isadora isn't designed for, nor tested with eGPUs nor machines with multiple GPUS. (See the "Unsupported Hardware Platforms" section of the Isadora 3 System Requirements TroikaTronix support article.)

Best wishes,

Woland

CitizenJoe

@woland said:

...consider getting a Windows computer with a single, powerful graphics card. You'll likely be able to spend less to buy or build a Windows machine that can handle outputting 4x 4k 60fps out of the box without having to use bunch of adapters and external hardware. Fewer pieces of hardware in the entire system means fewer potential points of failure and fewer chances to have hardware incompatibility issues.

This!

Cheers,

Hugh

Woland

@permyth

I asked around in the Office Hours Discord and got a few responses.

In response to me outlining my suggestion to go for a powerful Windows computer, one person wrote:

I'm sure you are right, but I thought I would mention that if you can dodge the dreaded orange dot by not having anything access the microphone then a basic M2 Mac Studio can support 5 4k60 displays natively. The Studio Ultra support 8 displays natively.

"Four displays with 6K resolution at 60Hz over Thunderbolt and one display with 4K resolution at 60Hz over HDMI"

This doesn't reduce the points of failure though, just the cost.

Another wrote:

Not sure it helps but we regularly output 3-4 4K video outputs to a DeckLink 8K Pro via a Sonnet with QLab from an M1 Mini 16GB. These are at 25-30fps rather than 60 but is considerably cheaper than a Studio. So am sure Izzy could do the same or better.

A third wrote:

I really like the decklink with Isadora fyi

Best wishes,

Woland