[Tim Kurkoski]

Jay, I’ve explained this a couple of times, but let me reiterate.

All of Adobe’s hardware partners, including AJA, Blackmagic, and Matrox, only support specific frame sizes and frame rates through their hardware. When you send their hardware a frame that doesn’t match a supported frame size or frame rate, some scaling must be done on that frame. Even those manufacturers’ own applications, like Blackmagic’s DaVinci Resolve, need to do this scaling.

The Mercury Transmit API allows these hardware partners to tell After Effects and Premiere Pro what scaling should happen when a frame does not match a supported frame format. AJA and Matrox use this part of the API. Blackmagic does not. We have asked them to do so. Their most recent drivers do not, but does have those new, alternate scaling option.

Yes, Adobe could, in theory, resolve this issue by providing some sort of scaling control in After Effects (and Premiere Pro, and SpeedGrade…). With the old, QuickTime-based video preview architecture, such a control was present because it was a necessity. But with Mercury Transmit this is not necessary because the API we provide to the hardware partners already provides them control over scaling. The problem that you and other Blackmagic users are having is generated because Blackmagic chooses not to utilize these scaling options available in the Mercury Transmit API.

Adobe will continue to engage Blackmagic about this issue.

[Tim Kurkoski]

Other people have reported that using the newer Blackmagic Desktop Video drivers do work with the older Multibridge cards.

I do happen to have a Multibridge Pro myself, and tested the 10.1.4 drivers on Windows 7, and it appears to be working. A 720×480 frame displays, though I do need to enable the new “unsupported frame sizes” option in Blackmagic’s Mercury Transmit settings dialog.

One suggestion on why NTSC sizes are not working in After Effects, but do in Premiere Pro, is that After Effects does not output interlaced frames. Blackmagic is very strict about their format definitions, and may not be accepting a 720×480 progressive frame as compatible with their defined interlaced formats. (This discrepancy is not a problem we have with the other card manufacturers.)

[Tim Kurkoski]

> I think Mercury Transmit lacks the scaling features? Or it just does not address this the right way to the hardware?

Mercury Transmit does include a protocol for scaling the output. The hardware must tell Mercury Transmit what size to scale to, then Mercury Transmit will do that scaling for each frame. AJA and Matrox take advantage of this feature in Mercury Transmit, Blackmagic does not.

In their newest drivers, 10.1.4, Blackmagic has added a new option for scaling the output in their Mercury Transmit settings, when it does not match a support frame size. You may choose to have the output centered or scaled. This is an option unique to Blackmagic, and does not utilize the automatic scaling functionality available in Mercury Transmit. You should try these drivers to see if this helps your workflow.

[Tim Kurkoski]

Try using the Effects & Presets panel instead of the menu.

[Tim Kurkoski]

> Is there a trick to making the 4k comp work?

Does your card support 4K output?

Blackmagic does not currently output frame sizes via Mercury Transmit that do not match the card’s native frame formats. This has been the case for a long time for Premiere Pro, and only started affecting After Effects with the addition of Mercury Transmit in After Effects CC 2014 (13.0).

In older versions of After Effects, you need to set the frame format for the card in the video preview Preferences, and After Effects scales the output frames as directed. With Mercury Transmit, After Effects (or Premiere Pro) automatically negotiates the frame format with the output device, and the scaling happens without the user needing to fiddle with settings. This works as intended with cards from other manufacturers, but Blackmagic has not yet implemented their side of the negotiation component, so no output occurs when there’s a mismatch between your comp size and the card’s supported frame formats.

Blackmagic has told us that they’re working on adding support for this in a future driver release. Until then, the only workaround would be to nest and scale your 4K comp into the largest frame supported by the card, and use that for external video previews.

[Tim Kurkoski]

Does a 1920×1080 sequence or comp preview through the Blackmagic card?

[Tim Kurkoski]

Chad, can you elaborate on “broken”? Does the Blackmagic device show up in the list of Mercury Transmit devices in After Effects and Premiere Pro? Does it output anything? What are the properties of the comp or sequence?

Have you tried rebooting or reinstalling the Blackmagic drivers, or rolling back to 10.1.1?

[Tim Kurkoski]

Thanks for reporting your success, Chris. I’ll keep that in mind for other people who have problems with older Blackmagic hardware.

[Tim Kurkoski]

Is your 2nd monitor plugged into the Blackmagic card? That would explain why Mac OS doesn’t see it as a monitor.

If you plug the monitor into your computer’s video display card, you should see the monitor in the OS and available in After Effects, as Adobe Monitor 2 in Preferences > Video Preview.

You can also use your Blackmagic card for preview in After Effects CC 2014. Make sure to download and install the latest Blackmagic drivers:
https://www.blackmagicdesign.com/support

When you do this, in Preference > Video Preview, a new device called Blackmagic Playback should appear. If you don’t see it, open Premiere Pro on that computer and look in Preferences > Playback for the same thing, and test whether preview works from Premiere Pro.

[Tim Kurkoski]

I am confused. Does your computer desktop appear on both of the monitors?

If Mac OS does not recognize the monitors, neither will After Effects. Please post a screen shot of your System Preferences > Display control panel.