var fs = require('fs');//引用文件系统模块
var ffmpeg = require('fluent-ffmpeg');

let dir = "/Users/john/Desktop/video3";
let newDir = "/Users/john/Desktop/videoNew";

var files = fs.readdirSync(dir);
console.info(files.length)

files.forEach(function (item, index) {
    ffmpeg(dir+"/"+item)
        .format("mp4")
        .videoCodec('libx264')
        .size('100%')
        .on('end', function() {
            console.log('【'+item+'】','file has been converted succesfully');
        })
        .on('error', function(err) {
            console.log('【'+item+'】','an error happened: ' + err.message);
        })
        .save(newDir+"/"+item);
})