DNXHR 444 don't export Alpha ( ok for tiff and exr )

Hi in Resolve 15b6 I can't export with a movie file format+alpha channel

The DNxHR 444 export a full white Alpha while exporting the same clip on an exr sequence export the alpha correctly

I tried in .mov and in .mxf files, on windows

Do you have an alpha output defined and connected?
Do you export Individual Clips?

Do you have an alpha output defined and connected?
Do you export Individual Clips?

Hello,
Yes the Alpha Output is connected And I'm exporting Individual Clips.

- This is working with tiff and exr
- This is not working with DNX 444 or 422 (the only possible movie candidate format)

This was with beta 6 but I don't see any updtae with the beta 7

Works for me with DNxHR 444 12 bit. I doubt 422 can contain alpha.

Ok, so it must be a windows related bug, we are on windows here.

Re-tested it just now and I can confirm it doesn't works on windows for Quicktime DNxHR 444 12bits while just switching to exr and I get a proper alpha channel.

PS: You're right for the 422 but I've checked it because Alpha Support for DNx422 is listed on the Resolve 15 New features so...

I'll confirm this on Windows.

I tried DNxHR 444 and Cineform RGB in a Quicktime container and could not get an alpha export for either (individual clips, export alpha option checked). A simple export of TIFF, other image sequence, and I get the alpha export.

I use the MXF container. Worth a try?

But a bug nevertheless, it works in MOV too here.

No issues with alpha exports using DNxHR444 10 bit and 12 bit on Mac OSX. Using Resolve 15b7.

Hello,
Any update on this ?
For the record the issue still there on 15.1 an is windows specific, there is no way to export a movie file with a valid alpha channel

And yet Fusion 9 can export DNxHR 444 12-bit with Alpha and Resolve 15 can read it in correctly. The only problem is that Avid can't read them. A bit off topic but related. I'm not sure why we can't get DNxHR 444 w/ alpha out of Resolve.

Maybe it's related to FFmpeg ? the only viable solution to write movie on windows and linux.
I'm sure somehow Blackmagic use that lib

the DNX FFmpeg implementation doesn't support alpha in so do Resolve ... ? BUT in FF the ProresCodec Do support Alpha but isn't available in Resolve...

Just bumping this once more for R16. Still doesn't work on Windows: DNxHR, 444 12b, export alpha w/alpha out hooked up in the nodes.

Does work with EXR, etc.

How has this been a bug for so long?

[Shrinivas Ramani]

Jed, Noel,

As with the previous tries, we can't see this issue on Windows or MacOS.

We could use a link to your logs and project export. I'm assuming you have your nodes connected to pass through alpha, and when selecting the codec, you have your Export alpha checkbox set in the Deliver job.

Please feel free to DM me the links if you feel that your project has sensitive information.

Regards
Shrinivas

Please feel free to DM me the links if you feel that your project has sensitive information.

Just sent a DM with more detailed steps to replicate & files -- thanks for checking in on this.

Resolve 17.4.3 (on windows 10) and this bug seems to still be present. Are you kidding me? Anyone tried exporting ProRes & alpha with voukouder plugin?

Update for Resolve 18.0.2
DNxHR + Alpha still not usable for intermediates
A timeline exported from DR with DNxHR in various subformats (those capable of delivering Alpha) cannot be used in Adobe Products. They show just black in colour and alpha.
When viewed with DJViewer I see the colour channels but alpha still shows black.
When reimported into DR colour and alpha behave just as expected. So DR has no prob with its own files.

The same settings exported from AfterEffects behave as expected in all mentioned applications.

My FHD test project in AE/DR consisted just of a text over transparent background. 50 Frames

It seems that export with CineForm + A works just fine in all applications. So at this time CineForm is the way to go for me. It´s also recommended by adobe as codec for intermediates https://helpx.adobe.com/de/premiere-pro/how-to/gopro-cineform-codec.html#:~:text=Der%20GoPro%20CineForm%20Intermediate%2DCodec,Qualit%C3%A4tsverlust%20in%20verschiedene%20Formate%20codieren.

Exporting with Alpha Channel attached stopped working for me all the sudden.

If I uncheck the Alpha box on the Delivery Page Render Settings it will Export.

I used every format and codec that will allow Alpha Channel (mov-h265, mp4-h265,etc)

The latest change I made to my computer was upgrade to osx Ventura from Monterey just this week.

No matter the Input clip or just a PNG image on the timeline when the Alpha box is checked,
I Get the ERROR: "Cannot find the appropriate codec for encoding the video frame."

Any suggestions would be much appreciated. Thank you

I reinstalled Resolve with no luck.
Resolve 8.1.2 Build 6
Macbook Air M1

Go back to Monterey. I did.

Uncheck Constant birate for DNxHR and try again. I think that may solve it.

Sent from my Mi 9T using Tapatalk

Go back to Monterey. I did.

Works Perfect now. Thank you

I too have had a lot of issues with Premiere Pro not interpreting Resolve's variation of different codecs with alpha channel support. I'm working in Windows 10 and I've tried every flavor of DNxHR and HD that support Alpha Channel rendering in addition to MXF formats. Premiere doesn't like any of these files if the alpha mode was set to premultiplied and Data Levels being set to Video instead of Full in the Delivery page.

My current workaround for now is exporting as GoPro Cineform 16 bit with alpha premultiplied whenever I need to render transparency. Premiere accepts it with no fuss.

I think I'm going to try testing Tiff and EXR next to see how it performs with VFX workflows next when delivering to NLEs outside of Resolve.

Update:

If you are having the render not finding the codec when exporting Alpha with H.265 using Quicktime or MP4 in OSX Ventura change the Encoding profile from Main10 to Main. I thought this would be fixed after a year of updates but it was not.

Quicktime / Apple ProRes / Apple Prores 4444 doesn't seem to have this issue and just works but the file sizes are huge.

My current workaround for now is exporting as GoPro Cineform 16 bit with alpha premultiplied whenever I need to render transparency. Premiere accepts it with no fuss.

Thank you so much for your help! You truly saved the day. I was attempting to send an Alpha file to a fellow editor who uses Premiere, but they encountered errors (specifically, 'Error Retrieving Frame'). They requested an AVI file, and while I initially tried using AVI with Grass Valley for the Alpha channel, the results were less than satisfactory. Your suggestion of using GoPro Cineform turned out to be the ideal solution. My colleague had no issues with it. Once again, thank you!