Decklink monitor & After Effects

Hey,

I have asked this on Blackmagic forum as well / Will update if I get new informations

I am trying to have a good monitoring of my work in After Effects (AE) using a Decklink monitor on mac (hackintosh, pci e).

There is a lot of things that I don't understand so sorry for the noob questions, but I can't find any information about that :

- Mercury Transmit activated on AE with Decklink monitor

- My config is a DELL U2412M > HDMI > Decklink monitor 4K, for now

- My composition is 25 fps : Error message, monitor don't support this (monitor is running native at 1920x1200 60Hz). Does it means that the Decklink is sending 25 Hz to the monitor and it doesn't support it ? Would a "real" video monitor support it ?

- On Resolve, on a 25 fps timeline, it works fine. Why ? Is it Resolve who convert 25 to 60 ? Do I see 25 or 60 Hz ?

- On AE : 50 or 60 fps composition, it display an image. BUT : the playback on the monitor is not sync with AE. On the monitor, it is slower, and it stops seconds after I press "stop" (space bar) and the composition has stop playing.

- On AE : my monitor is 1920x1200, my comp is 1920x1080, but the decklink display it vertically stretched on the external monitor, so it takes all the display area. Can't seems to find how to correct it.

It seems like I am doing everything wrong. I really need help from more experienced people.

- Can I, with a decklink monitor, and a pc monitor, have a real 25/30/50/60 fps monitoring on AE ?

- What hardware do I need to see real progressive AND interlaced output ?

- I do motion design, now for the television, and I need to see my animation @17212882 fps 1080i in order to see if the animation is displaying fine.

I would really appreciate your help !