Re: Video to ASCII effect

You've probably set your character size too small if you only see the bounding boxes ;-)

I've commented Dan's expression for you. Hope it helps you to understand it :-)

One other thing, you can make your own set of characters ranging from light to dark. I wasn't really fond of the "@" as the darkest character so I've altered the desity string to suit my taste.

Here's the commented expression;

density = " .'`,^:" + '";~-_+<>i!lI?/|()1{}[]rcvunxzjftLCJUYXZO0Qoahkbdpqwm*WMB8&%$#@';

/* "density" is just a string ordered with characters from light to dark (" " is white and "@" is black).You can access each character from this string as an array. "density[1]" would be "." since array entries start counting by zero (desity[0] = " ") */

target = thisComp.layer(index -1);

/* the target variable will hold the reference to the layer above the texts layer where you've added this expression */

cols = 80; //number of characters/columns that make up the width of the grid
rows = 60; //number of characters/rows that make up the height of the grid

w = thisComp.width/cols;
// dividing the width by the number of columns gives you the width of each "cell" in the grid

h = thisComp.height/rows;
// dividing the height by the number of columns gives you the height of each "cell" in the grid

s = "" // this declares an empty variable to hold the string that makes up your ascii art

// Next comes a nested loop that makes it all happen...

for (var i = 0; i < rows; i++){ // adding the rows

/* the value of "i" is zero, repeat this action while "i" is smaller than the number of rows, increment "i" with one after each execution of the embedded script */

//the real nested loop

for(var j = 0; j < cols; j++){ // adding the columns to the row

/* the value of "j" is zero, repeat this action while "j" is smaller than the number of columns, increment "j" with one after each execution of the script */

center = [w/2 + j*w, h/2 + i*h];

// divide the width/height of the cell in half and add j times the width/height to that value results in the centre-point of each cell

sample = target.sampleImage(center,[(w-1)/2,(h-1)/2]);

// uses the "center" variable for the position and sets the size of the point to be sampled based on the size of your grid-cells. sample will hold an array of three numbers between 0 and 1 (1=white and 0=black)

s += density[Math.round(linear(sample[0],0,1,0,density.length - 1))];

// the variable "s" is incremented with a character from the "desity" string. The expression between the straight brackets uses the first value of the sampled color in the sample variable to produce an integer/rounded number which is used to select the character to add to the string "s"
}
s += "r"; // After a row is completed this adds a new line to the text until all rows are built.
}
s // in the end the completed string is echoed by this simple notation and this is what shows up on the text layer.