Alpha Key Sync issue

[ThomasN]

Hi there,

I was hoping to get some help with a problem with alpha keying. I'm trying to create an Alpha key from a video being played within Arena and going into a vision mixer. So we have the alpha key generated by Arena's Alpha effect on one output and using the same video source as fill on the another output. We can get both into the vision mixer and they appear fine until we use it as an alpha key. The key and fill are out of sync resulting in part of the video disappearing in part and white where it should be video. The main problem is that the sync keeps changing, even when the vision mixer & Arena are timed together. If it was a fixed time we could delay by x frames but as it is changing the delay wouldn't work. We have tried outputing from Arena on the same graphics card & different graphics cards, same issue.

We are outputing 1080i50 as the vision mixer has to have 50i input.

Test video was 30fps, 2 seconds long. We have many different clips that we would like to use this effect on so doing it in Arena is much easier and quicker than re-rendering everything again and playing from another source (plus we don't have another video player)

I've been looking through the forum but couldn't see anything so if anyone has done this or has some ideas on how to fix / work around this issue.

Thanks,

[Oaktown]

A few questions:

When you're using one GPU, what outputs & adapters are using?

What GPU are you testing with?

What's your layout in arena?

Have you tested with clips that are rendered at 25p?

[Meptik]

Are you using a BlackMagic SDI card as your output? Or a GPU? Are all outputs coming off the same card?

[Shamai]

im having the same issue
my fill output was using the regular hdmi port and the alpha key was using a mini displayport to hdmi adapter and then i switched it to use the intensity shuttle output and still no luck

asus rog
resolume 6
i7 6th gen
24gb ram
6gb nvidia graphics

[Empyfree]

I’ve had my best success with this using two matches outputs. For example I’ve used the two mini display ports on my Mac. But using the Hdmi and one DisplayPort is way out.

Best result by far is from a Datapath FX4!

[Shamai]

it would be nice if resolume can sync normally instead of using another piece of hardware to do something so basic
unless someone has another way that i can output into blackmagic atems with an embedded alpha channel