How would I make a 40 millisecond long clip in after effects?

Discussion in 'Digital Video' started by Nckcard, Nov 2, 2008.

  1. Nckcard macrumors regular

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    Jul 11, 2008
    #1
    I'm trying to make a video for a science project with images in it so short only the subconscious mind can notice them (A.K.A. 40 milliseconds), does anyone know how i could make a picture flash for about that long in adobe after effects, or maybe even iMovie HD?
     
  2. bigbossbmb macrumors 68000

    bigbossbmb

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    #2
    i doubt you can do it in iMovie.

    with video, you're limited to standard framerates... for things shown on typical broadcast TV, that is 30fps. 720p is 60fps which is the highest rate for any broadcast standard. So if you make a 720p comp in AE, a one-frame flash would be as fast as you can get (1/60 of a second).
     
  3. Nckcard thread starter macrumors regular

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    #3
    But couldn't you time stretch it from there to 1% of 1/60th of a frame?
     
  4. bigbossbmb macrumors 68000

    bigbossbmb

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    #4
    you can, but you're output will still be 60fps. ultimately the still will still be there for 1/60 and all the time-stretch would do is probably make it more faint.
     
  5. Nckcard thread starter macrumors regular

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    #5
    Well is there any way you know of in any kind of program you can think of that I can do this in? I really need to get it done, please help in any way you can.
     
  6. Pikemann Urge macrumors 6502

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    #6
    Here's what I think you might do. Get yourself a strobe device. I think they are the same thing as flashguns but they have variable timing etc. Channel that through a slide projector and, boom, problem possibly solved. Of course I don't know how many ms the flash bursts are but it's possible that the machine's specification list will tell you.

    Sorry I couldn't be of more help.
     
  7. Nckcard thread starter macrumors regular

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    #7
    Are there any other options? i need to have these 40ms frames hidden in a video.
     
  8. Pikemann Urge macrumors 6502

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    #8
    Hang on a minute here. What's 1 ms? Is it 0.001 sec? What's 40 ms? That's 0.040 sec, right? If that is correct, here are some interesting figures:

    25fps: 1/25 = 0.040 sec

    29.97fps: 1/29.97 = 0.333 sec

    50i: 1/50 = 0.020 sec

    59.94i: 1/59.94 = 0.016 sec

    So it seems that one PAL frame or two PAL fields are what you want. (?!?!)

    EDIT: If I am right you could do this in iMovie.
     
  9. Nckcard thread starter macrumors regular

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    Jul 11, 2008
    #9
    Ok, that sounds right. How would i do that in iMovie..?
     
  10. Pikemann Urge macrumors 6502

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    #10
    Right, here's what you do. Get the clip you want to edit. Make sure it's 25fps ('cos 40 ms is what you want, obviously). Split the clip where you want to insert the single frame. Take the end of the first half or the beginning of the second half of the original clip and remove one frame. Insert a still photo (make sure it's the same dimensions or at least the same aspect ratio).

    Drag that photo into the timeline (make sure you select clip view, not time view). Right click on that photo, select Show Info..., then change duration to 0:00:01.

    I hope you can follow that.
     
  11. arjen92 macrumors 65816

    arjen92

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    #11
    Just that you know: 0a:0b:0c:0d
    for the letters you can fill in numbers like: 1:15:30:12

    the a stand for hours, the b for minutes, the c for seconds and the d for frames, so the d is not for milliseconds or whatever but frames, so it depents on the format you use what d will be.

    in the example it's 1 hour 15 minutes 30 seconds and 12 frames (which is almost halve of a second)
     
  12. Cromulent macrumors 603

    Cromulent

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    #12
    Why? Are you trying to do subliminal messaging in your videos?

    Edit : Ignore, read the original post properly again :).
     

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