Jump to: Board index » General » Fusion

Fusion alpha output transfered to the timeline

Learn about 3D compositing, animation, broadcast design and VFX workflows.
  • Author
  • Message
Offline

Binsfeld

  • Posts: 30
  • Joined: Tue Mar 26, 2019 10:37 am
  • Real Name: Jean Huot

Fusion alpha output transfered to the timeline

PostTue Dec 06, 2022 10:40 am

Hi,

I want to do a chroma key with delta keyer in fusion, then having my keyed clip over a background clip under it in the timeline.

Sounds simple right ?
Well, I might be missing something...I can't properly do it :

On the screenshot you can see :
- My timeline
- My key in fusion
(excellent, I want to go back to the timeline and see the checkers replaced by the layer under it ....well nooooo it would be too easy.)
- So I add a 2nd media output on channel 1
- Link that alpha channel to the alpha output in colors...
and I get this white noise around the border of my keyed subject.....

FusionKeyAlpha.jpg
FusionKeyAlpha.jpg (133.75 KiB) Viewed 441 times


Pulling hairs, asking here.
is anyone having an Idea how to properly do that ?
Offline

Sven H

  • Posts: 336
  • Joined: Mon May 24, 2021 9:11 am
  • Real Name: Sven Hegen

Re: Fusion alpha output transfered to the timeline

PostTue Dec 06, 2022 3:23 pm

resolve has problems interpreting the alpha correctly.
I'm not at the machine atm but you can try if premulting helps.

also another workaround would be to plug the alpha into all 3 rgb channels and use the rgb from the second input in color and plug it into the alpha of the node
Offline

Sam Steti

  • Posts: 2003
  • Joined: Tue Jun 17, 2014 7:29 am
  • Location: France

Re: Fusion alpha output transfered to the timeline

PostTue Dec 06, 2022 5:24 pm

Hey

I'm into this the whole year along with other comp stuff, but in Fusion Studio so not in Resolve Studio. Just for you to know that my advice is influenced by my own workflow ;) ...

Now, since your start is on the right tracks, why wouldn't you make the whole key in the Fusion tab instead of going back to the edit and try to make it with a track underneath ?

So if you feel like it, select your 2 stacked tracks and right click to Make a fusion clip. Go to the Fu tab;
Pull your key - the best* you can - on the S.Klaus girl and add a merge node : the sofa is now on the BG input of the merge node, SK on the green FG input...
This goes into one single media out node afterwards, now go check the result on the Edit page.

*There are so much to write here about green screen keys. Aside from lighting the green BG or taking a great attention to the edges or light wrap in the comp with the right dedicated nodes, too many people think it's a couple of click trick to make it, I've been experiencing that for years (fortunately, they're also consequently as much happy too when finding out more and more tricks to pull keys properly ;) )


So find how to use a CleanPlate node too (feeding the pink input of the delta keyer), and don't hesitate to add a saver node to export your scene from the fusion tab to check, to avoid the Resolve support of alpha in the Edit
*MacMini M1 16 Go - Ext nvme SSDs on TB3 - 14 To HD in 2 x 4 disks USB3 towers
*Legacy MacPro 8core Xeons, 32 Go ram, 2 x gtx 980 ti, 3SSDs including RAID
*Resolve Studio everywhere, Fusion Studio too
*https://www.buymeacoffee.com/samalaplaya
Offline
User avatar

Olivier MATHIEU

  • Posts: 515
  • Joined: Thu Aug 04, 2016 1:55 pm
  • Location: Paris/Grenoble, FRANCE

Re: Fusion alpha output transfered to the timeline

PostFri Dec 09, 2022 2:34 am

Just an Input about Resolve 18.1 new feature
MediaIn Node has the ability to see a video mix down of all the tracks (in the timeline) under the clip you are working on in the fusion Tab
New media in Node ➧ "Media Source" Menu ➧ background
Resolve Studio 18.1.2 & Fusion Studio 18.1.2 | MacOS 12.6.2 | GUI : 3840 x 2160
CPU : i9 10900X | RAM : 64 Go (2666Mhz) | GPU : RX 6800 XT 16 Go | NTW : 10 G/s
Offline

Binsfeld

  • Posts: 30
  • Joined: Tue Mar 26, 2019 10:37 am
  • Real Name: Jean Huot

Re: Fusion alpha output transfered to the timeline

PostFri Dec 09, 2022 10:31 am

Thanks guys,
3 interesting ways to test.

Sven, I tried premultiply as the alpha option of the clip but it changed nothing.

Sam, yes, I think it is the intended way of doing things proprel.
I would have prefered to have fusion passing through the alpha so I can iterate the video backgrounds and their position in time easily.
I know I have to learn fusion extensively now, DeltaKeyer with the cleanplate node pulls the best keys I ever saw. Keylight, primatte, and every other ones I tried can't compete.

Olivier. Oh, cool, I have to try that, It might be a great solution if it dynamically changes the background input regarding my changes in the lower track of my timeleine. But I might be expecting too much. I guess it is not "Track" related, that new mediaIn option.

I'll tell you how it goes.

Thanks.
Offline

Sven H

  • Posts: 336
  • Joined: Mon May 24, 2021 9:11 am
  • Real Name: Sven Hegen

Re: Fusion alpha output transfered to the timeline

PostFri Dec 09, 2022 2:19 pm

Binsfeld wrote:Thanks guys,
3 interesting ways to test.

Sven, I tried premultiply as the alpha option of the clip but it changed nothing.

Sam, yes, I think it is the intended way of doing things proprel.
I would have prefered to have fusion passing through the alpha so I can iterate the video backgrounds and their position in time easily.
I know I have to learn fusion extensively now, DeltaKeyer with the cleanplate node pulls the best keys I ever saw. Keylight, primatte, and every other ones I tried can't compete.

Olivier. Oh, cool, I have to try that, It might be a great solution if it dynamically changes the background input regarding my changes in the lower track of my timeleine. But I might be expecting too much. I guess it is not "Track" related, that new mediaIn option.

I'll tell you how it goes.

Thanks.

when I wrote about premulting I meant doing it inside of the comp. Changing the alpha option on the clip happens before the fusion comp even begins. that's why it doesn't change. but I figured that doesn't seem to matter anyway. the issue lies in the node sizing you apply in the color tab. at least this way I could reproduce the problems.

Return to Fusion

Who is online

Users browsing this forum: nnjrewzas112 and 7 guests