DXV Alpha channel not rendering - Help!

[Empyfree]

I’m trying to render some DXV’s from Apple motion using Compressor.

I’ve got the DXV codec installed, in fact I’ve just ditched everything, trashed the library presets, and reinstalled everything.

I've created two "Compressor" destination settings. One has DXV3 High Quality "With Alpha" and one is DXV2 with "preserve Alpha" chosen

When I add a file into compressor and choose either DXV output setting everything looks ok. Digging into the codec setting shows that the option to preseve the alpha has been turned off. I can turn it back on here and it retains this setting.

No matter what I choose, the alpha is ignored when I process the files and drop the resulting files into Arena. Arena shows the files as having No Alpha.

Rendering the same Apple Motion project as an Quicktime Animation works correctly, the alpha channels are preserved.

My next project has footage over triple HD width, and I really need to be using DXV's to keep things smooth!


Anybody got any ideas? I'm stumped!

[Joris]

Yes, this is a known issue with Compressor 4.2.0 and above.

The problem is that after you apply a preset, the codec settings revert back to the first option, which is DXV3 Normal Quality, Without Alpha. You can see this yourself when you check settings of the file (so not the preset) in the video tab.

After you set the codec settings back to the correct setting, it renders okay.

This is very annoying, and affects all versions of Compressor above 4.2.0. If you can still get your hands on Compressor 4.1.3, it will work as expected.

I've filed both a consumer and developer bug report with Apple. If you want to help make them aware of this problem, you can file a report here: http://www.apple.com/feedback/compressor.html

[Empyfree]

Cheers Joris (and thank you for the email!)

I've tried changing the codec settings back once applied to the video, still no luck

I've just tried using Adobe Media Encoder and got the same results. Must be something in my setup. Probably the software gremlins telling me it's time for a re-format and start again!

[Oaktown]

In Adobe Media Encoder, make sure you're using the max rendering depth (32-bit) in the video settings when you render DXV with alpha or the alpha channel won't be preserved during the encoding process.

[Empyfree]

In Adobe Media Encoder, make sure you're using the max rendering depth (32-bit) in the video settings when you render DXV with alpha or the alpha channel won't be preserved during the encoding process.

Cheers Oaktown. I've abandoned my mac at work for the night but will give this a shot tomorrow. I'm going to fire up my home mac after supper and see if I can duplicate the issues.

Out of interest, how hard is it to write or duplicate a codec? Would it be within the realms of possibility to have four codecs, with no options, rather than one codec with four options...?

[Oaktown]

I did some testing and I can't seem to get DXV3 with Alpha to work either with Compressor 4.3 whether I try to render a file or a sequence from Motion 5.3!

On the other hand I have no problems when I use QuickTime 7 Pro version 7.6.6 so if you have that, you might want to give it a try but unfortunately I don't think Apple is selling registrations for QT7 Pro anymore

[Oaktown]

I was able to get my hands of Compressor 4.1.3 and I confirm that it works fine with DXV3 and alpha.

[Empyfree]

I still haven't had any luck with Compressor, but thank you for the tip regarding Adobe Media Encoder and the 32bit render depth. I'm now sharing from motion as QuickTime Animations and then dropping them through Adobe. Murder on disc space!

[mrpaulmahon]

I have found the exact same problem with trying to render out an alpha channel from Motion5 with Compressor 4.3. Has anyone found a work around for why this is the case yet? I just purchased Compressor as well, and can't seem to find a way to go back to an older version.

[Oaktown]

I don't believe there is a workaround to render alpha with Compressor 4.3 yet!

You may have to get your hands on Compressor 4.1.3 in order to streamline your workflow if you want to to go that route.