gistfile1.txt

// $ node rename.js
var fs = require('fs');
var path = '/Users/max/Downloads/test/';
fs.readdir(path, function(err, files) {
    files.forEach(function (val, index, array) {
        if(val.match(/mp4$/)) fs.renameSync(path + val, path + unescape(val));
    });
});