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Video with Alpha Channel won't work...

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James Villeneuve
Video with Alpha Channel won't work...
on Apr 9, 2014 at 7:25:21 pm

Hi there. I feel like mashing my face on the keyboard.

I cannot seem to get video with alpha channel to work on my timeline. Here's what I know and tried.
Video Types - ProRes 4444 with alpha/DNxHD with alpha/Quicktime Animation with alpha.
Clip settings in Info Menu - Straight/Premultiply
I am NOT using proxy media or optimized media. I'm working straight from the original files.

Potential issues - my FX dude is exporting from AfterEffects on a PC not a mac… problem? My FX dude may not be using proper settings. I've seen the other post on export settings. Tried them. They don't seem to make a difference. I can import Targa's with alpha and they work fine. But then I tried exporting targa sequence from Compressor 4 with ProRes with Alpha Channel preset and it won't work on my timeline.

What. The. Eff. Is there a bug or setting that I'm not aware of?

My system is a dual quad core 2.4 ghz tower with 20 gigs of Ram and I'm running 10.09 on Mountain Lion.

Any suggestions or magical solutions would be appreciated. Thanks a bunch.

James, Toronto


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Jeremy Garchow
Re: Video with Alpha Channel won't work...
on Apr 9, 2014 at 7:44:05 pm

Check the "alpha" channel in the viewer. Is it all white?

If so, there's no alpha in the file.

Do you have any other video software on your computer? Ae, Motion, etc?


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James Villeneuve
Re: Video with Alpha Channel won't work...
on Apr 12, 2014 at 1:35:57 am

thanks so much for the response. i've been working crazy days and haven't been able to get back to this until just now.

I checked and, in fact the alpha wasn't translating - I looked at the alpha channel in the drag down menu and the frame is entirely white rather than a white 'cut out' alpha channel. So something about the output isn't agreeing with FCPX. Because my FX guy tested it on his side and said the alpha channel was displaying properly in other programs.

Just to compare, I did it with an imported image with alpha file and viewing the alpha channel clearly showed the alpha channel. So it's just with video… dammit.

I'm thinking this might be a bug or something …

James.


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Jeremy Garchow
Re: Video with Alpha Channel won't work...
on Apr 12, 2014 at 1:53:12 am

I have had no problems with alphas and fcpx.

I would guess it's from the creation of the original movie. I'm not sure how you can render ProRes 4x4 with alpha out of Ae on a PC, but I've never had to do it, so there's that.

Leaving an inadvertent layer on during the render may cause the problem, or they are not choosing to render RGB + Alpha in the output module with millions or trillions+.

Is it possible to post one full resolution second of it?

There's also an option to render alpha only put of Ae, which you can then composite with the original layer in fcpx with stencil or silhouette luma.


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Nick Toth
Re: Video with Alpha Channel won't work...
on Apr 9, 2014 at 7:51:29 pm

Do you have "optimize media" turned on in import prefs? If so, turn it off and re-import.

anickt


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James Villeneuve
Re: Video with Alpha Channel won't work...
on Apr 12, 2014 at 1:37:46 am

thanks very much for the reply. I am aware that optimize media would create prores 422 and destroy alpha so I had that turned off. My guess is there is a gremlin living in my machine. It's the only thing that makes sense at this point.

I'd love for this to just work as it would simplify my life.


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Chris Northcross
Re: Video with Alpha Channel won't work...
on Apr 9, 2014 at 7:59:38 pm

Ran into this problem with PNG image sequences from Blender. Apparently, there's a bug in compressor that wrecks the alpha channel in an image sequence if you export out to ProRes4444.

If you have access to Motion, (or Quicktime 7 or After Effects) use that to import your image sequences and export them as your ProRes clips. Not nearly as efficient if you've got a bunch of image sequences as there isn't a batch export available in Motion that I'm aware of, but at least you get to keep your alpha channel.

"Whether you think you can or can't, you're right."


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James Villeneuve
Re: Video with Alpha Channel won't work...
on Apr 12, 2014 at 1:41:10 am

hiya. Thanks for the tip. The prores 4444 videos with alpha channel were originally exported with After Effects on a PC. I do have Motion (though I barely know how to use it). When I have time to try it, that'll be my next move. Is it a bug you have experience often or something you have heard from other users?


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James Villeneuve
Re: Video with Alpha Channel won't work...
on Apr 12, 2014 at 1:48:38 am

I did manage to get my FX guy to output video with alpha channel that finally worked in FCPX. But it was Uncompressed 32-bit ARGB and is obscenely huge. 83 MBs for less than a second of video for testing. If he had output all my materials that way it would have been something like an entire terabyte for less than 6 mins of stuff. It would probably make my aging machine explode.

Anyhow, it looks Motion is my next try. I'm going to import an image sequence with alpha and export as ProRes 4444 and see if that works.

Computers are awesome until they suck.


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James Villeneuve
Re: Video with Alpha Channel won't work...
on Apr 16, 2014 at 12:30:53 am

So, to conclude my story, I finally was able to try exporting an image seq from motion into a prores 4444 codec and bring it into FCPX. It worked like a charm. So, that means that the issue has something to do with my FX guy's outputs. I was worried that I had a bug/bad computer setup that was making all my efforts futile. My FX guy is now doing his own research into the problem to figure out what he's doing wrong.

Many thanks to you all for taking the time to offer suggestions. It was all very helpful as I was able to learn more about FCPX while figuring out my problem.

James.


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