-
Random jump cuts to audio
Hello
I am currently working with a time remapping script that makes jump cuts to a random location within a clip every .44 seconds
Is there a way to modify the expression pasted below to make it so the jump cuts occur corresponding to changes in an audio track or keyframes generated from an audio track? In other words, every time the audio level jumps above a certain threshold I would like to jump cut to a random location within the clip
Any tips would be infiny appreciated
Thanks so much!!
Anna
segDur = .44;// duration of each "segment" of random time
minVal = inPoint;
maxVal = outPoint - segDur;seed = Math.floor(time/segDur);
segStart = seed*segDur;
seedRandom(seed,true);
startVal = random(minVal,maxVal);
endVal = startVal + segDur;
linear(time,segStart,segStart + segDur, startVal, endVal); -
1 Reply
-
I wouldn’t recommend doing this purely through expressions. If you think the current expression is slow, you would not like the result, and likely it would be impossible to use the expression for footage longer than a minute or so. Expressions have no memory, so the expression would have to look through all previous frames for the audio levels and calculate the result newly for each frame. By the time you get to the one-minute mark, the expression would have to check all 1500 frames backwards, etc.
A better, but somewhat labor-intensive approach would be to insert markers manually wherever you want the scene to change, based on the audio waveform. Then you can use the number of markers as random seed.This expression borrowed from Dan’s MotionScript site gives the last marker number:
n = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n--;
}
}If you insert markers and add this line to the expression plus change the random seed line to
seed = n;
you should get a different section from the footage every time there is a marker.More information on triggering animations with markers at https://www.motionscript.com/design-guide/marker-sync.html
Kalleheikki Kannisto
Senior Graphic Designer
Reply to this Discussion! Login or Sign Up