Rendering from deliver page with alpha channel not working

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Michael McCaffrey

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  • Joined: Tue Apr 14, 2015 1:30 am

Rendering from deliver page with alpha channel not working

PostWed Jun 13, 2018 4:27 pm

So... no file outputs from Fusion. So I have to render to file from the deliver page. Im trying to render out an green screen key of an interview on an alpha channel. (because resolve is constantly losing all my caches, even the fusion caches and color caches and even the disk caches on the media out node in Fusion). So to avoid having to re-render these interview clips constantly, I need to just render it out to file and edit the file back onto the timeline. Now the problem here, is that the key looks fine in fusion and in the edit page and in the deliver page. BUT...when the computer starts rendering the clip, it adds this ugly white line around the subject. I am rendering ProRes 444 and I have checked to export alpha transparency. So basically in Resolve, so far as I can tell, it is impossible to render a file that has an alpha channel. Would be REALLY great to have a file output node in Fusion to render a clip to disk. And secondarily, have the deliver page render alpha channels correctly.

It seems like a premult issue but there are no transparency settings to rendering from the deliver page. Its either on or off.

Screen Shot 2018-06-13 at 9.21.32 AM.png
Screen Shot 2018-06-13 at 9.21.32 AM.png (78.44 KiB) Viewed 372 times
Configuration:
Resolve Studio 15.2
Windows 10 Pro
16 Core AMD Ryzen Threadripper 1950X. 64GB RAM
Dual GTX 1080 Ti's
24TB RAID
Intensity Pro 4k
(1) 1080P Display, (1) 27” Display, (1) HPz24 1080P Display for Grading
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Peter Cave

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Re: Rendering from deliver page with alpha channel not worki

PostThu Jun 14, 2018 1:09 am

For me it's only the Fusion page that does not output an alpha when rendering on the Deliver page. If I use the 3D keyer (or other qualifiers) on the Color page the alpha is rendered correctly.
Resolve 15
Mac OSX 10.13.3
iMac (Retina 5K, 27-inch, Late 2014)
4 GHz Intel Core i7
AMD Radeon R9 M295X 4096 MB
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Dwaine Maggart

Blackmagic Design

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Re: Rendering from deliver page with alpha channel not worki

PostThu Jun 14, 2018 5:37 am

Please try 15b5.
Dwaine Maggart
Blackmagic Design DaVinci Support
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Michael McCaffrey

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  • Joined: Tue Apr 14, 2015 1:30 am

Re: Rendering from deliver page with alpha channel not worki

PostThu Jun 14, 2018 4:36 pm

Dwaine Maggart wrote:Please try 15b5.


Tried twice. As soon as I hit render in the deliver page I get a beach ball and Resolve gets hung up. Finally force quit the app after a few minutes of no activity. So I was unable to confirm the alpha channels.
Configuration:
Resolve Studio 15.2
Windows 10 Pro
16 Core AMD Ryzen Threadripper 1950X. 64GB RAM
Dual GTX 1080 Ti's
24TB RAID
Intensity Pro 4k
(1) 1080P Display, (1) 27” Display, (1) HPz24 1080P Display for Grading
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Peter Cave

  • Posts: 822
  • Joined: Thu Aug 23, 2012 6:45 am

Re: Rendering from deliver page with alpha channel not worki

PostFri Jun 15, 2018 4:49 am

Dwaine Maggart wrote:Please try 15b5.


Does not output alpha channel from a fusion Ultrakey. Rendered using individual clips mode at source resolution on r15b5.
Resolve 15
Mac OSX 10.13.3
iMac (Retina 5K, 27-inch, Late 2014)
4 GHz Intel Core i7
AMD Radeon R9 M295X 4096 MB
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Abdelrahman Magdy

  • Posts: 250
  • Joined: Fri Jan 23, 2015 10:08 pm

Re: Rendering from deliver page with alpha channel not worki

PostFri Jun 15, 2018 8:58 am

I also can't find any option to export the alpha from the Deliver page.

If I create an MXF VFX Connect clip encoded in DNxHR 444 and check the 'Export Alpha' option, that works pretty well. But there doesn't seem to be a similar option in the Deliver page, and when I just render an MXF also encoded in DNxHR 444, the alpha is not carried out.

Additionally, the release note mentions this:
Added support for encoding EXR clips with alpha channels
However, I can't seem to find any option to do that, neither in the Deliver page or from the VFX Connect clip.

This is tested with 15b5 on my Linux machine.
System specs:
Resolve Studio version: 15.0.0.086
Fusion Studio version: 9.0.2
OS: CentOS 7
CPU: Intel i7-4790k 4GHz Quad-Core
RAM: 32GB
GPU: NVIDIA GeForce 1080 Ti 11GB

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