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Activity Forums Adobe After Effects Expressions Using after effects Typewriter Preset animation to be triggered by audio of typewriter

  • Using after effects Typewriter Preset animation to be triggered by audio of typewriter

    Posted by Glenn Wright on February 19, 2013 at 7:42 pm

    I am new to expressions but I want to use After Effects typewriter text animation preset but have the Range Selector linearly move to the audio (typewriter sound effect) keyframes. I own Sound Keys but still haven’t found a way to use the keyframes since they don’t go up in percentages or decimals.

    Any help with an expresion would be much appreciated.

    Thanks

    Davis Lindsay replied 13 years, 2 months ago 3 Members · 3 Replies
  • 3 Replies
  • Dan Ebberts

    February 19, 2013 at 8:29 pm

    Your keystroke sounds are all in one audio file, is that correct? If so, I think it’s going to be tricky to detect them. You might be able to do it with a script that analyzes the audio keyframe data a drops markers where the peaks are, but it would likely just give you an approximation. If it worked well enough, an expression could be crafted to drive the character reveal based on the number of previous markers. It would take some time to get it all set up though.

    Dan

  • Glenn Wright

    February 19, 2013 at 9:37 pm

    Hey Dan,

    Yes I have converted the audio file into keyframes with Sound Keys and set them to both linear and none(integrate). Hoping that would create a linear number I could pick whip to so the Range Selector would count up to 100 but the numbers for Sound Keys jump to 100 with in 10 keyframes which is much to quick.

    I am really wanting a way to convert those Sound Keys keyframes into a numeric number that counts 1 integer at each keyframe but so far no luck.

    Thanks
    Glenn

  • Davis Lindsay

    February 20, 2013 at 3:26 am

    Hey Glenn,

    This solution works with peak of range and instant falloff.

    You’ll have to convert each expression to key frames after each step.
    This is found under animation > key frame assistant > convert expression

    1 : Simple part, if the audio is below 100 it becomes a zero.

    2 : You may need to relink your sound keys in this part.

    3 : Almost done, relink the slider variable.

    remember to convert expression to key frames after each step.

    hopefully this helps
    regards,

    //1
    //add this to your sound keys output property.

    Math.floor(value/100)

    //2
    //Create an expression slider on the same layer of your sound key effect
    //Add this to the slider

    sound = effect("Sound Keys")("Output 2");
    n = sound.nearestKey(time).index;
    a = 0;
    if ( n>1){
    a = 1;
    }
    current = sound;
    past = sound.key(n-a).value;
    if (current == 1){
    current - past;
    } else {
    0;
    }

    //3
    //Add this to your range selectorâ

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