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How do I edit a clip with an ALPHA channel into a segment / timeline?

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Dean Fragola
How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 24, 2013 at 11:51:47 pm

Hi,
I just bought a stock-clip with an Alpha channel, but I'm not sure how to edit it into my timeline?
Do I just edit it directly into V1? ... and then do I need to put a key effect on it?
Do I edit it into V2 over another clip?
Do I need to open sub-tracks and then try and put it on like V.1 or V.2?
Do I need to put an effect on it and then adjust parameters?
I'm pretty baffled at this point as so far it just sorta looks like a negative clip with a moving outline.
I appreciate anyone who can help me.
Thanks.


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John Pale
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 25, 2013 at 2:41:04 am

Sounds like the alpha is inverted.

You have a few choices. Here is the easiest.....

delete the clip you imported including the media.


Let's try this again....

In the import dialog, change the alpha setting to the opposite of what it is set to now. If its set to "Do Not Invert", then set it to Invert. If its set to Invert, set it to "Do Not Invert"

If you reimport and now see the graphic as more than just an outline...you are done. Just put the clip on a higher track and the Alpha should be transparent. You do not need to add an effect to it. It should have a Matte Key icon on it already. If it doesn't, you have the import dialog set to "ignore alpha"

If it still looks incorrect, you may have a graphic with a Premultiplied alpha...which does not work correctly in Avid. You need to go back to the program it was created with and re do it with a Straight alpha.


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Dean Fragola
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 25, 2013 at 10:36:37 pm

Hi John,

Thank you very much for helping me ... as I'm new to this ALPHA channel stuff, so I really appreciate your patience ... and your advice.

And I'm happy to say that your initial idea/suggestion worked great (In the import dialog, change the alpha setting to the opposite of what it is set to now. If its set to "Do Not Invert", then set it to Invert. If its set to Invert, set it to "Do Not Invert") ...

As I now have the media imported and looking good as a MATTE KEY piece of media ... and when I edit it onto a segment in the Timeline it look good (and I can adjust the foreground level with no problem once I open the effect editor) ....

However ... the only problem is, AVID won't let me adjust the "scaling" in the parameters? .... am I doing something wrong? ... or is a matte key just not able to be scaled? ...

If I try and move the scale parameters in the effects editor, the image disappears and I just have a black screen. And I'm not able to nest in and adjust the scaling either ... and if I try and drop an image resize effect onto the MATTE, Avid just tells me that "effect cannot be applied".

Thanks again for all your help.


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John Pale
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 26, 2013 at 1:44:25 am

Promote the effect to 3D in the lower right corner of the Effect Editor. Then all the scaling controls appear, as well as a host of others.


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Dean Fragola
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 26, 2013 at 11:26:45 pm

Hi John,
Thank you so much ..... as your advice has been dead-on perfect both times. As you were exactly right in that I just needed to hit the 3D button in the lower right hand corner of the effects editor -- as that now gives me all kinds of parameter options including scaling with the ALPHA channel footage.
Thanks again as you're a life savor .... as prior to you giving me advice, I was literally about to completely give up on trying to use the ALPHA clip content ... as I couldn't import it properly nor alter it's parameters.
Thanks again.
Dean


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John Pale
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 27, 2013 at 12:10:39 am

No problem. Glad to help.

Unfortunately, this aspect of Avid is completely non-intuitive, especially if you are coming from other NLE's. Unless you do a tutorial, take a class or read the manual its unlikely that you will guess how it works.

Much of the effects model is unchanged from the 1990's, though they have tacked on many new capabilities. If they were designing the UI from the ground up, it would most certainly not work like this.


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Dean Fragola
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 27, 2013 at 4:11:59 pm

Hey John,

Thanks again, as I really do appreciate it. And I'm thankful for any tutorials I can find on Youtube ... plus forums like this one where people such as yourself can help me out (otherwise I'd be lost).

And just one other quick question regarding having a clip in the source monitor in AVID ... I've tried to open up "motion effect" so I could then slow it down, but AVID won't let me ....... so I'm assuming that you can't do motion effects on a piece of source content that has an ALPHA channel?

Thanks.

Dean


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Juris Eksts
Re: How do I edit a clip with an ALPHA channel into a segment / timeline?
on Aug 28, 2013 at 1:22:11 pm

Quite correct Dean, you can't put a motion effect on your clip because the Alpha is locked.
The way round is slightly long-winded but -

Step into the clip, copy the picture part to the clipboard, open a new timeline, paste the picture to the timeline. Do the same with the Alpha channel.
So you've got a timeline with the picture content and the alpha content (Black and White) on the timeline.
Do a video mixdown of both.
You can then do motion effect as desired, on both.
Next put the picture part on V2, the Alpha part lined up above, on V3.
Put a Matte key effect onto the B+W alpha clip, (you may have to swap the sources).
And Bob's your Uncle!


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