Apha channel

DaVinci Resolve

Apha channel

Posted by Robin Erard on July 9, 2011 at 2:16 pm

Hello,

I have finished the editing of a short with a lot of motion design.

I have two video track

V1: DPX of the film, color graded
v2: Prores4444 with Alpha Channel (motion design track)

Is there a way to compose both in DaVinci ? I used “Compositing mode” with screen or Add, but there is no way to use Alpha chanel. An idea ? And if it’s not possible, it could be good to be able to use Alpha chanel in the compositing mode.

It would be very usefull to be to be able to import subtitles or other graphics (via a prores4444) directly in Davinci.

Best
Robin

réalisateur, scénariste, monteur, étalonneur
http://www.robinerard.ch

Robin Erard replied 14 years, 10 months ago 2 Members · 5 Replies
5 Replies

Rohit Gupta
July 9, 2011 at 2:38 pm

Hi Robin,

Currently embedded alpha channels are not supported. If you extract the alpha channel as a separate clip, you should be able to use that as a matte to composite V2 and V1.

You just feed the matte to the “Alpha Output” in the node graph.

Regards,
Rohit
Robin Erard
July 9, 2011 at 2:53 pm

Hello Rohit,

Thank’s for you very fast answer.

I gonna try that. Do you plan to allow the alpha chanel support in the “compositing mode” ?

it could be usefull for a lot of things :

– subtitles
– motion graphics
– opening credit, closing credit

Like that we wouldn’t need to go into AfterEffect or other compositing software to finish a film.

You did a very good upgrade with V8, it’s a pleasure to work with it.

All the best

Robin

réalisateur, scénariste, monteur, étalonneur
http://www.robinerard.ch
Rohit Gupta
July 9, 2011 at 3:02 pm

Thanks – glad you like V8.

You can use alpha channel, just not the embedded alpha channel in the clip. If you bring the alpha channel as a separate matte clip, you can use that to do the composite.

Right-click on the node graph to add an alpha output, and feed the alpha channel from the matte through in the node graph.

Hope my explanation is clear enough.
Robin Erard
July 11, 2011 at 1:41 pm

Hello,

Is a matte could be a Quicktime or it must be a TIFF sequence ?

Best

Robin

réalisateur, scénariste, monteur, étalonneur
http://www.robinerard.ch
Robin Erard
July 11, 2011 at 2:06 pm

Hello,

I found the answer. It’s possible to use a matte from a prores4444.

Open Nuke :
Read the prores4444
write only the alpha in a new prores4444 and use it as matte.

that’s all

Best

Robin

réalisateur, scénariste, monteur, étalonneur
http://www.robinerard.ch

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