Export Alpha Fails

When exporting (Format QuickTime, Codec H.265, Export Alpha) I get the following error message while rendering:

CleanShot 2024-01-12 at 02.58.58@2x.png (541.8 KiB) Viewed 689 times

The rendering works when I deselect "Export Alpha".

CleanShot 2024-01-12 at 03.03.16@2x.png (464.49 KiB) Viewed 689 times

Is there a workaround - or is it just a bug?

See screen recording:

Details:
VERSION 18.6.4 BUILD 6
Mac mini, 2020
Chip Apple M1
Memory 16 GB
macOS Sonoma 14.2.1

Hey
Is it the same if you select ProRes 4444 as the output codec ?

It works with ProRes 4444.

According to Apple, only ProRes 4444, or HEVC, supports alpha channels. Thus one would expect checking the "export alpha" while using HEVC should work.

Ok

So I cannot write anything more because 1/ I've always used PR4444 when alpha is needed (export and import ways) and 2/ I only export masters from Resolve which leads to 3/ if I need an H265 (or anything else than ProRes actually since it's the codec of what I export from Resolve)), I wouldn't give the mission to Resolve but to another shutter encoder-like tool like Handbrake or whatever, and thus cannot comment on Resolve's behavior in a situation I never experience...

But we can tell that "a classic" workflow can be used without issue, better than a real dead end I'd say...

This page from Larry Jordan may help: https://larryjordan.com/articles/includ ... evc-video/

This page from Larry Jordan may help: https://larryjordan.com/articles/includ ... evc-video/

Thanks Peter, that is helpful.

This page from Larry Jordan may help: https://larryjordan.com/articles/includ ... evc-video/

Hey, still me...
It indeed looks interesting, specifically the Services way actually.
Now, honestly, I don't want to be the joy flap guy, but I wouldn't take the risk to use that format in a project where I'm not sure the alpha channel of the file would be ok when imported anywhere (meaning in any piece of app). This just in the context where you're further in a project and it happens that you have to treat it again for any reason... It looks like you cannot rely on it as you can with ProRes 4444

But interesting anyway... Thx

I am experiencing a very similar issue when using Davinci Resolve 18.6 on an Apple MacBook Pro M1 Max (macOS Sonama v14.4.1).

I am using Resolve to export green screen signers footage as HEVC 'Export Alpha' (.mp4), in order to produce a video file of the signer with a transparent background - used later for dual stream (switchable) rendering on our decoder. This has, and still continues to work as expected when rendered and output using a Mac Pro (Intel-based Trashcan), but always fails on the M1 MacBook with the same error noted earlier in the thread;

ERROR: Render 1 Job failed as the current clip could not be processed. Cannot find appropriate codec for encoding the video frame.

Screenshot 2024-04-30 at 15.29.32.jpg (815.07 KiB) Viewed 31 times

If I render the file as a standard HEVC (mp4), not selecting the 'Export Alpha', it runs fine and encodes using HEVC - albeit without the transparent background required.

The Mac Pro is running an older version of the 18.0 Resolve so tried rolling back the MAcBook to the next nearest copy I could get hold of (v18.1.4. build 9). However, even after installing and rebooting, I still get the same error on the M1 MacBook.

I'm beginning to think this is an M-chip architecture/Resolve issue as HEVC is obviously present on the machine, its just for some reason it always fails when trying to encode the 'Export Alpha' only. This means I am now restricted to only being able to produce renders on the older (slower) Mac Pro and cannot run sample transcodes when on the move.

Any thoughts or suggestions?

(Note: Further details of exact software/macOS versions for the Mac Pro can be added later as I'm currently away from my home desk).

Thanks in advance...