Extract pixel info at a certain position in frames every second-ish in a video stream

detect.js

#!/usr/bin/env node
/* eslint-env node */
'use strict';

var fs = require('fs');
var path = require('path');
var Canvas = require('canvas');
var Image = Canvas.Image;

var canvas = new Canvas(720, 406);
var ctx = canvas.getContext('2d');

function extractPixel(file, x, y, fn) {
  fs.readFile(file, function(err, buffer){
    if (err) {
      throw err;
    }
    var img = new Image();
    img.src = buffer;
    ctx.drawImage(img, 0, 0);
    var px = ctx.getImageData(x, y, 1, 1);
    fn(px.data[0], px.data[1], px.data[2], px.data[3]);
  });
}

var file = path.resolve(__dirname, './foo.jpeg');
fs.watchFile(file, {interval: 20}, function () {
  extractPixel(file, 1, 1, console.log.bind(console, '%s rgba(%s, %s, %s, %s)', new Date()));
});

stream.sh

#!/bin/bash

ffmpeg -i rtmp://fms.12E5.edgecastcdn.net/0012E5/mp4:videos/8Juv1MVa-485.mp4  -r 1 -f image2 -updatefirst 1 -y foo.jpeg