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PPro v2 chroma keys - help?

Aug 5, 2012 7:33 PM

I'm working on a movie clip, I'm following lesson 13-4 from the PPro classroom in a book, and I want to use the chroma key to key out the sky in the sequence and superimpose an alien sky onto this clip. I've got a still image of an alien sky.


Here's what I did so far: I moved the video clip from Video 1 up to video 3 and the still image to video 1. Currently I'm trying the drag the Chroma Key from the Effects panel onto one of the video tracks as indicated in the lesson, but I keep getting a symbol that is a circle with a slash through it as I try to drag the chroma key onto one of the video tracks.


I'm a bit confused as to where exactly do I place this chroma key in order to key out the sky at this point - in the video 1, video 2 or video 3 tracks and do I place it before the clip starts or after the clip ends?


How can I drag the chroma key onto the appropriate track without getting this "no" symbol?


Also, I'm a bit confused by the instructions from this lesson - first it says to drag the the photos onto the video 1 and the video 2 tracks (but currently I'm working with only 1 photo at this point) and then it says to place the photos after the clip you worked on earlier - what exactly does this mean?



Thanks in advance.

  • Currently Being Moderated
    Aug 6, 2012 9:55 AM   in reply to angelalien548

    I only use cs3 and dont have that lesson you are following. but typically you drag the effects on top of the video you want that effect to work on. So you dont drop it before or after the clip but right on top of the clip... the no symbol should disappear when over the clip.


    good luck !

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    Aug 6, 2012 2:44 PM   in reply to angelalien548

    Dont drag the effect onto the track, but drag it onto the clip you want to key.

    Track one is for your alien sky

    Track two is for the video that has been keyed.

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    Aug 9, 2012 4:25 AM   in reply to angelalien548

    Did you animate the Garbage Matte over time?

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    Aug 9, 2012 1:00 PM   in reply to Ann Bens

    what youre trying to do is why people shoot stuff with green screen and blue screen etc ( chroma key ) ...where the background becomes transparent and you can drop in whatever you want in its place. Since you didnt do that with the bus, and have a 'sky' the chroma key filter is not seeing one "field " of color to make it basically eliminate it.


    sooo, if you try to use the chroma key to block out that background you'll also get other tonal ranges and colors elminated in your image you want un-affected ( the bus moving etc and not just the " sky " ).


    Sooo, unfortunately thats your first problem and is hard if not impossible to do.


    secondly, using a matte ( as ann pointed out ) you would need to animate it frame by frame to keep up with the bus you want to preserve. In other words,  you'd need to draw a section of the image you want to eliminate ( or save same thing but just opposite ) ..and animate it to follow the "action".


    It's really tedious and hard to do cause you have to deal with so many frames of " change " if you matte it out...and animate the matte.


    The program will do a lot of tricky stuff to tween the frames as best it can, but in the long run you really should shoot stuff without having to spend all that time ( frame by frame ) rotoscoping the thing....blocking out what you want to keep and what you want to get rid of.


    However, people do tend to give you a lot of leeway in their minds about what is " believable " when it comes to a bus going to another planet... so if you animate the matte like Ann suggested, it might work out OK !  How cool it THAT ? !


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  • Currently Being Moderated
    Aug 19, 2012 12:29 PM   in reply to angelalien548


    sounds like fun, doing the 3d stuff etc..lots to learn.


    I only have cs3 so dont know about version 2 and what you can or can't do. A lot of people here will probably remember that version though, and help you more.


    Also, I have maya and only use that ( and don't use it that much at all because like you I am learning how to use it and it is complicated for my snail - like brain ).


    However, in terms of general work flows maybe I can mention a few things that will help.. and just remember I'm talking about maya and cs3.


    I also have windows xp and mousey computer, so I can really only work with SD movies. HD makes my computer gasp for breath.


    So I set up my projects in maya with the idea that in the end I will export it for SD to go into cs3 with that...

    Consequently I have several options on the exports from maya...

    a) numbered still images

    b) avi movie



    I have found that the numbered still images are nice to work with in cs3.


    So I set up the project in cs3 for export to SD, which means even though I'm using numbered stills from maya ( with alpha channel ) I set up my project as SD NTSC 720x480 and choose par to suit my 4:3 or 16:9 aspect ratio ( usually I use 16:9 with par of 1.2 ).

    Then I also choose a video renderer in new project that matches what I'm going to export more or less ( usually lagarith avi ).


    In CS3 the alpha channel comes in with the numbered stills and that is where I drop in whatever background images or stuff I want to add ( like what you were saying about using chroma key to make a new sky ... the alpha channel is transparent, so you just add that sky without chroma key necessary ).


    wav files are nice to work with in CS3 and I've never had any problems with them.


    hope some of this helps and good luck and have fun !


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  • Currently Being Moderated
    Aug 19, 2012 3:23 PM   in reply to angelalien548

    premiere pro cs3 editing program


    I dont have your version

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