is there any workaround to sync 4 x 4UHD output from a MAC Studio Apple M1 Ultra ? TIA

is there any workaround to sync 4 x 4UHD output from a MAC Studio Apple M1 Ultra ?

Thanks in Advance !


  • Short answer: no.

  • Hello @keithkeat,

    It is not possible to sync outputs from the Apple M1 Ultra's GPU.

    You could use a Blackmagic Decklink 8K Pro inside a Thunderbolt chassis, but your would be limited to 4 x 2160p30 (not 4 x 2160p60 because of the Thunderbolt bandwidth). In this case, be sure to run the Decklink as a whole 4320p30 output to get frame-sync outputs (use video-routing in Millumin if needed.

    Best. Philippe

  • Hi @Millumin , @ectoplasmosis & @keithkeat ,

    We just tried to output 2 UHD signals from a M1 Mac Studio via Thunderbolt and two UltraStudios 4k Minis. The sync in the Blackmagic devices is locked (also visible in the output (E2)) for a long time it works brilliant - but the two signals lost reference for a few seconds every now and then. As soon as a new column starts in Millumin, the sync returns after a few seconds.

    Do you know the problem or have an idea?

    Best. Lukas

  • Hello @lukas_tech,

    Synchronization between several Blackmagic devices is not a fix : this is a feature.

    Indeed, everything should be both synchronized at software level (Millumin) and at hardware level (Blackmagic Decklink or Ultrastudio). We are still working on the first thing, and the second thing can be achieved with sync-signal, so there is nothing to code about this.

    Keep in mind that this is a something that is very advanced, because all Blackmagic outputs are working asynchronously on the computer's side (even if on the Blackmagic's side, this is synchronized via a reference). To my knowledge, I am not aware of any software handling this properly (except maybe expensive media server such as Disguise, but I did not test them with Blackmagic devices).

    We hope to come back to you in the next months. Thank you for your patience.

    In the meantime, using a Decklink 8K Pro is a solution, because it can be used a giant 4320p60 output (that you can then use with a video-routing in Millumin for example).

    Best. Philippe

  • Dear Philippe, @Millumin

    because struggling on another topic atm, i was just curious if there are any updates regarding implementation timeline on this topic?

    Best, Lukas

  • Hello @lukas_tech,

    No ETA at the moment, because we have been busy with other features. Sorry.

    However, this is still planned and important to us. Thank you for your patience, I hope we will have more news by the end of the year.

    Best. Philippe

  • We have used a Mac Studio Ultra with a Decklink 8k

    It ran for 3 days and as far as we could tell it was in sync. The important thing to remember is using 1 canvas.

  • We do basically the same with Decklink 8k in our MacPro. Works perfectly in sync when using 1 canvas.

    Unfortunately this works only in 8 Bit. If I change to 10 Bit in workspace settings, the gradient shader from millumin shows same banding issues as when using 8 Bit.

    I could only get 10 Bit when using RGB encoding, but this doesn't work in 8k mode of the Decklink (hardware limits of card). Any ideas? :(

  • Hello @lukas_tech,

    According , the Decklink 8K Pro supports : 10, 12-bit RGB 4:4:4 up to 1080p30, and 8, 10-bit YUV 4:2:2 in all standards.

    In 10-bit mode, Millumin supports 10-bit RGB but not 10-bit YUV (this requires much more resources to be encoded than 8-bit YUV). Do not hesitate to create an idea on Uservoice, so we could keep track of this request and see if other users are interested.

    Best. Philippe

  • edited May 20

    Hello Philippe,

    thanks for your reply. I simply did not know that 10-bit is only supported in RGB mode. Thanks :)

    So unfortunately no option for us to output 8Kp50 in sync (as one canvas) because Decklink 8K is limited to 8Kp30 in RGB and AJA Kona 5 seems not working with Millumin?

    Best, Lukas

  • Hello @lukas_tech,

    The AJA compatibility might be not up to date.

    Later this year, we planned to upgrade the SDK used by Millumin, to support latest devices from AJA.

    Best. Philippe

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