The expression randomly displays the footage frames. Applies to Time Remapping.

fr = 5; // Frame rate, if set to 0 (zero), then one frozen frame will be displayed;
numFrames = 15; // The number of frames from the sequence to be used
seedRandom(index,true);
seg = Math.floor(time*fr);
f = Math.floor(random(numFrames));
for (i = 0; i < seg; i++)
f = (f + Math.floor(random(1,numFrames)))%numFrames;
framesToTime(f);