Importing and Exporting Alpha Channel

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Level 1

18 points

Importing and Exporting Alpha Channel

Hi,

I have a Flash video (FLV) with an alpha channel (I don't have access to the original QT video). I used Adobe Media Encoder to convert it to Quicktime to import into FCP X to make a quick edit and export back out. How do I ensure that the video imports into FCP X with the alpha channel and exports back out with the alpha channel? I set Adobe Media Encoder to encode the alpha channel, but how can I tell if it imports into FCP with the alpha and exports back out with the alpha? Is there a way to check that in FCP? After I exported it out of FCP, converted it back to FLV and imported it into Flash, it no longer had the alpha channel. Not sure where I lost it along the way. When I exported out of FCP, I chose Apple ProRes 4444.

What things do I need to make sure I do in each of these converts, imports and exports and how can I tell if the alpha channel is there in FCP X?

Thanks,

Brian

Posted on Mar 27, 2012 2:09 PM

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Answer 1

Best reply

dredcomm

Level 2

360 points

Mar 27, 2012 2:29 PM in response to Sullyville

The top right corner of the Viewer in FCPX has a dropdown menu where you can select what Channel to view. You can choose the Alpha Channel there. ProRes 4444 and Animation are both codecs you can use within the .mov format to retain an alpha channel.

~D

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Answer 2

Sullyville Author

Level 1

18 points

Mar 27, 2012 2:34 PM in response to dredcomm

Thanks. That helps a lot (when I searched the help files for alpha channel, it didn't show that). I just chose alpha from the drop down and it is plain white. DOes that mean no alpha channel came into FCP with the video? Is there a certain way to import that will make sure the alpha channel imports? I don't know for sure that it has the alpha still when I converted in Adobe Media Encoder (even though I checked for it to encode the alpha channel).

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Answer 3

dredcomm

Level 2

360 points

Mar 27, 2012 2:40 PM in response to Sullyville

If it's all white then there is no alpha. You probably lost it in the encoding process.

Try encoding to an Animation or ProRes4444 QuickTime movie with an alpha.

~D

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Answer 4

Sullyville Author

Level 1

18 points

Mar 27, 2012 2:54 PM in response to dredcomm

I just tried to convert the FLV (that i know has an alpha channel) to Quicktime ProRes 4444 and then to Quicktime Animation codec and imported into FCP and the alpha channel wasn't there. I know this isn't an Adobe forum, but do you know if Adobe Media Encoder can convert an FLV to those and keep the alpha channel? If not, any idea how I should be doing this? I don't have the original video, just the FLV that I've been using inside of a Flash swf.

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Answer 5

Mar 27, 2012 3:22 PM in response to Sullyville

You can just use QuickTime Player 7 to convert from .flv with alpha to Animation-Millions+ or ProRes4444.

QuickTime Player 7 should be on your system install disks.

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Answer 6

Sullyville Author

Level 1

18 points

Mar 27, 2012 3:44 PM in response to stuckfootage

Thanks for all the help. I tried to open the FLV file in my QuickTime 7 Player Pro and it said I was missing components to open it and only opened the audio. Any ideas?

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Answer 7

Mar 27, 2012 3:51 PM in response to Sullyville

When you install Adobe CS, it should install the Flash components here:

/Library/QuickTime/FLV.component

If you don't have that component, you can install Perian:

http://perian.org/#download

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Answer 8

Sullyville Author

Level 1

18 points

Mar 27, 2012 4:45 PM in response to stuckfootage

Thanks. Tried those. Still not bringing the alpha channel into FCP (probably not exporting it from QT7). I get no options on export to choose Animation or ProRes 4444.

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Answer 9

Sullyville Author

Level 1

18 points

Mar 27, 2012 4:57 PM in response to Sullyville

Actually, I do get those options and ProRes 4444 - which gave an error and then tried Animation and it exported. But after I imported into FCP, just got a big white box when I looked at alpha channel in FCP.

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Answer 10

fox_m

Level 6

12,208 points

Mar 28, 2012 1:18 AM in response to Sullyville

If you converted to QT from the outset from AME, I don't believe the alpha channel exists in the MOV file. You don't say what format you exported to, but anything other than ProRes 4444 or Animation would have "flattened" the video. Alpha channels do not exist in most video codecs including H.264, they're unsupported. Your original Flash w/alpha channel has to be On2 VP6 format. If ProRes 4444 is an option for export in AME - use that! otherwise, QT7Pro with the Perian Component should be able to open up the On2 VP6 file directly. Use QT7Pro to transcode that video into ProRes 4444 (preferred) OR Animation (with the appropriate alpha settings) and try importing that into FCPX. To test for transparency, just drop one of the generators below the storyline under that clip. If there's transparency, you'll see portions of the generator show through.

Exporting from FCPX is the opposite: export at "Current Settings" (should always be ProRes 4444) and use AME to convert it back into .flv format. If AME ignores the alpha channel in PR4x4, use QT7Pro to convert to the Animation (w/alpha) format before using AME.

Without the original QT video, I would prepare myself for a loss of quality :/

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Answer 11

Mar 28, 2012 4:29 AM in response to Sullyville

The idea of using QuickTime 7 is a good one.

It is not enough to export in Animation or ProRes 4444 format. Make sure you have also chosen "Millions of Colors+" (note the PLUS sign: this is what indicates that you are exporting an alpha channel). Just "Millions of Colors" does NOT export the alpha channel.

Message was edited by: Luis Sequeira1 to add screenshot

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Answer 12

Sullyville Author

Level 1

18 points

Mar 28, 2012 5:27 AM in response to Sullyville

Thanks for all the thorough help. To clarify, here are the steps I'm trying now:

QT 7 Pro: import an FLV that has an alpha channel (I assume this because when I bring this FLV into my flash movie, the background is transparent - my subject walks on screen and you can see the graphics of the flash FLA behind him as was intended).

Export out of QT7 Pro as Apple ProRes 4444 with Millions of Colors+ (get an error trying this: Failed qtKitErrorCatchAll (-8061))

Export out as Animation with Millions of Colors+ (see screen shot - exports fine)

Import file into FCP X

In FCP X, drag the clip into timeline and it says Video propoerties not recognized and defaults to Format: other, resolution 640x480 and rate: 23.98p (but I've tried other formats it allows too with the same results). With All selected in the Channel drop down, I see a white box in the first frame of the movie, then the movie plays with a black background. When I choose Alpha in the Channel drop down, I only see white in the display screen. With all selected in Channel drop down, I put a generator behind the video, it doesn't show through. There is a black background around the subject of my video, which all indicates to me that no alpha channel is being recognized.

I export out of FCP as QT ProRes 4444 (it gives no options for millions of colors+ or other).

Use Adobe Media Encoder to convert to FLV (see screen shot included), settings: FLV, Encode Alpha Channel checked, etc.

Import into Flash FLA, subject is on a black background instead of transparent background.

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Answer 13

Mar 28, 2012 9:38 AM in response to Sullyville

Let's divide this problem into two halves. First of all, are you actually creating a movie with an alpha channel? Instead of testing with FCX, open the movie in Photoshop. You should see the background as a checkerboard pattern.

If not, then you're not creating the movie correctly, and that has nothing to do with FCX.

If you do see the checkerboard pattern, then you are creating the movie correctly and the problem is in FCX.

Once you do that test, we can proceed.

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Answer 14

Sullyville Author

Level 1

18 points

Mar 28, 2012 10:18 AM in response to stuckfootage

I know I have a movie with an alpha channel, but it's in FLV format. I brought it into QT7 Pro and exported it out using Animation with Millions of Colors+. Then brought that into FCP. I just opened it in Photoshop as you suggested, and all I see is white - no foreground or background. That, along with the other stuff I've tried, makes it seem as though QT7 is not exporting with an alpha channel correctly.

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Answer 15

Sullyville Author

Level 1

18 points

Mar 28, 2012 11:03 AM in response to Sullyville

In case this is helpful, I have posted the FLV file that has the alpha channel that I want to convert and bring into FCP.

http://www.sullyville.com/intro.flv

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