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cal@eskimo.com
cal@eskimo.com
New Participant
July 16, 2020
Question

Baffled by not getting compositing with Alpha Channel Material

  • July 16, 2020
  • 2 replies
  • 430 views

I am stumped by how Premiere and After Effect workflow handles Alpha channels.

In the Bad old days of 1" and Digital Video Tape, we used to have graphic artist create two passes of video tape with matching timecode. Pass One, was the color "hero" video, and Pass two, had the Alpha Channel for compositing. Matching timecode made everything duck simple to edit and composite with live video switchers. We would synch roll the Alpha Channel and the "Hero" pass video to do our effects compositing.

 

This even worked on Non-Linear Henrys and Hals and Harriettes. 

This is still being done in Live Broadcast productions with Chyron/Vidifonts/TypeDeko character generators, with color/rgb signal and alpha channel video feeds. 

 

Both products-- Premiere and AFX,  DO NOT Behave in this manner no matter what i try. I have use the VideoEffect/Keying/TrackMatteKey function after viewing several tutorial videos and NOTHING close to what i want to do--- which is a simple plate video and hero animation ride over the plate video cleanly --- can this be achieved????

 

Any Advice on how to approach this workflow?

 

Calvin

 

    This topic has been closed for replies.

    2 replies

    R Neil Haugen
    R Neil Haugen
    Brainiac
    July 16, 2020

    What work are you doing with this, btw? More info is almost always more better ...

     

    Neil

    Everyone's mileage always varies ...
    M
    Meg The Dog
    Inspiring
    July 16, 2020

    How are you applying the track matte?

    The order on the timeline should be

    Background: V1

    Fill: V2

    Matte: V3

    Track Matte effect applied to Fill clip on V2, getting the matte source from V3 Luma:

    MtD

    cal@eskimo.com
    cal@eskimo.comAuthor
    New Participant
    July 16, 2020

    Hi MtD.... That is EXACTLY how i arranged my Video TIMELINE Layers. THE plate or Background is the lowest level.  AND I have tried that--- and in MANY combination --- i get the drop down menue and options. NOTHING works as i expect it to do. As mentioned, I am doing a test footage that involves a Plate video, and having a 3-d animation slide infront of the plate video, and you should see the plate video going on while the animation plays in the foreground. What happens is, the moment the Alpha Channel Rendered video that runs insynch with the hero animation hits into frame, it completely blocks the Plate video. There is not clip/keying adjustments to make sure the ALPHA (white over black) video is providing the cookie cut for the Hero video to play over the plate video. With the older video switchers, you had a key clip or threshold level that you can play with. 

     

    BTW... the Alphas Channel Video was created in After Effect/Adobe Media Encoder, from a 3-d rendering outputing in TGA\A mode. In Photoshop you can see there is an Alpha Channel that MATCHES the Hero Image.  The Hero video, was made in AFX. Both were created in AFX and AME. 

     

    I have tried to use the Ultra Key feature... Again...not working at all. 

    Calvin

    cal@eskimo.com
    cal@eskimo.comAuthor
    New Participant
    July 16, 2020

    Opsss... Sorry i have feel like an idiot... BUT actually reading Mtd's response DID exactly what i wanted!!!

    Counter to what i expected... WHY Matte Luma? Why doesn't the Matte ALPHA work? BUT hey... I got what i wanted!!!  Here is the Photographic Proof...(but some more photoshoping to blur somethings like file names)  THANKS MtD!!!

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