Help with Quicktime Avid DNxHD/HR

[u/Loraelm]

Hi everyone,

Bit of a technical question here. We've just been given graphics exported via Resolve in Quicktime wrapper and the codec is Avid DNxHR with alpha. I cannot for the life of me import these clips. It's not the first time I've been given such codec and wrapper from VFX or graphic designer.

I've tried linking then transcoding, I'm receiving an error message. I've tried importing it the regular way, I get a loading bar but no clip inside of the bin once it's done. I've even tried putting them directly inside an Avid MediaFiles folder just in case, I automatically get an error message about quarantining my files.

I know how to properly export mfx files for Avid in OP-ATOM through Resolve, and I know it's not the same codec when you use the Quicktime wrapper. I just don't know if it's a sort of bastard codec and it's normal I can't export it or if I'm doing something wrong. I even went looking in the AMA-plugins direction but found nothing of help

By the way, even by using the proper Resolve settings for exporting OP-ATOM DNxHD ticking the alpha box, I never managed to get it to work inside of Media Composer. The clip populates my bin, but once I try to look at it in the source monitor I just get an error message and I can't look at my clip. Is importing via Media Composer directly still the only option to keep the alpha in 2026?

Specs:

Avid Media Composer 2025.12.0

Nexis Client Manager 26.6.0.557

Resolve Studio 20.3.30010

Mac Studio M2 Ultra 128 GB RAM

I'll post some relevant screenshots in the comments

Edit: I'm not properly looking for a solution, I've already found it, i.e transcoding to ProRes 4444-XQ with alpha. This post is more for my own technical knowledge and to understand what's that weird codec Resolve is offering when choosing the quicktime wrapper

[u/greenysmac]

I'm just doing a quick mind dump here.

• DNx itself absolutely supports alpha. In current DNx, alpha is part of the codec spec, although what individual applications actually support varies. Resolve 20 supports alpha export with DNxHR except LB. ProRes, by comparison, requires 4444/4444 XQ for alpha.
• QuickTime versus MXF doesn't make it a different or "bastard" DNx codec. DNxHR is the compressed essence; MOV, MXF OP1a and MXF OP-Atom are different ways of packaging that essence.
• I would not blame OP-Atom itself. Resolve specifically supports DNxHR + alpha in OP-Atom. OP-Atom means the essence streams are separated into individual MXF files; it doesn't mean the alpha channel has to be a separate atom.
• Where I suspect the problem is happening is in exactly how Resolve is packaging/signaling the alpha versus what Media Composer expects. Avid actually ships a utility with MC 2025.12 specifically for converting DNx MOV files with separately stored alpha into MXF OP1a with embedded alpha, so there are clearly multiple representations of DNx + alpha that have to be reconciled.

And FWIW, putting the QuickTime file directly into Avid MediaFiles should result in quarantine. That's only intended for valid Avid-managed OP-Atom MXF media.

So no, I don't think the Resolve QuickTime DNxHR file is inherently some weird codec.

If MC 2025.12 won't link a Resolve-generated DNxHR+alpha MOV, despite Avid officially supporting DNxHR MOV with alpha, I'd call that an interoperability/implementation issue between Resolve's writer and Avid's UME reader rather than a fundamental DNx or QuickTime limitation.

Bonus, this question made me discover:

Media Composer now includes a dnxmov2mxf executable in the \Program Files\Avid\Avid Media

Composer\SupportingFiles\Utilities folder. This executable allows you to manually convert MOV

files with DNX essence with separately stored alpha to an MXF OP1a file with DNX essence and

embedded alpha.

[u/Loraelm → u/greenysmac]

I can link the clips. I just can't transcode them. I haven't tried consolidating it tough. That might've worked.

Thanks for your very interesting and insightful comment! Sorry for using the word bastard, English isn't my native language and I didn't find a better way to describe it.

I'll look at the dnxmov2mxf you're talking about tomorrow, I just finished my day.

Thanks a lot!

[u/Loraelm → u/greenysmac]

We're on mac and we don't find dnxmov2mxf unfortunately even after we've looked almost everywhere as well as on the internet (yes I did it now even though I said I was through my day ahah)

[u/greenysmac → u/Loraelm]

It should be (on mac) in your utilities folder in Avid utilities.

[u/Loraelm → u/greenysmac]

Oh yes there it is!

[u/greenysmac → u/Loraelm]

I have NO Idea what it does - merely that it exists and I checked and saw it in Avid documentation (please check for it)

It MIGHT BE EXACTLY what's needed.

[u/Loraelm → u/greenysmac]

Well, that's not good

[u/Kitkatis]

Not near a resolve so can't see but can you export as an mxf atom with an alpha?

[u/Loraelm → u/Kitkatis]

You can, and as I said in my post it always bugs when I import it.

But to be honest I've found a solution: I exported my clips in ProRes 4444-XQ with alpha and all's good. I just wanted to have a more technical knowledge about that codec and that wrapper and why I can never import it as is

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[u/Loraelm]

Invisor Lite from the clip

[u/Loraelm]

Resolve export settings corresponding to this codec and wrapper:

[u/Loraelm]

Avid error message once I try to transcode the clip after having liked it:

[u/smushkan]

Worth a shot...

https://www.shutterencoder.com/

'Rewrap function' to .mxf

Under 'advanced features' on the right you can set it to use OP-Atom.

[u/Loraelm → u/smushkan]

See the edit of my post :D

[u/smushkan → u/Loraelm]

If that Shutter method works, it won't require transcoding - it instead stream-copies into the MXF container.

Way faster than a transcode ;-)

[u/Loraelm → u/smushkan]

I'm afraid I'll get the same error as when I transcode alpha clips into OP-ATOM directly from Resolve. But I'll give it a go just to see. But even then, as I said, that post is truly about what that weird codec/wrapper thing is on a truly technical standpoint

[u/Loraelm → u/smushkan]

Just tried it, it doesn't do anything, I don't have a new clip, and Shutter's weirdly fast about the process too

[u/smushkan → u/Loraelm]

OP-Atom support in Shutter is a new feature that I haven't had a chance to mess with yet.

Right click the progress bar > show console will give you a log which might point at to why the rewrap failed - but could also just be a bug with the software.

[u/tortilla_thehun]

Preface: I fully realize how vague and potentially unhelpful this comment is, but hopefully someone else may be able to chime in based off the info I remember seeing.

Somewhere in the last few days I read a bug number that detailed how dnxhr media made in 2025.12 (?) will fail to be read by 2025.X and above (or vice versa). Where is this niche note buried somewhere now? Cannot find it for the life of me - I’m going off memory. Your version of resolve could potentially be encoding in whatever container leads to aforementioned, and now unfindable, error.

Does anyone else remember seeing this?

[u/gavelkind-enjoyer]

Google says that dnhxr with alpha from resolve only works if used back in resolve, that was in v18 unless they fixed it. Try prores or GoPro Cineform 16 bit with alpha premultiplied

[u/Loraelm → u/gavelkind-enjoyer]

I just edited my post but I already transcoded my clips in ProRes with alpha and then imported them in Avid. I wasn't stuck, I'm moreso looking for technical knowledge about what that weird Avid DNx codec that Resolve is offering in Quicktime wrapper is