how can i use multer to upload a video and force the format to be mp4

I have implemented imaged upload using multer and I am receiving the images back to my front end app built with angular. Now I want to do the same with video, upload the video such that I accept all video formats but store on mp4 or other acceptable formats. I have searched everywhere but cant not seem to find out if multer can process video. Here is my implementation so far.

const router = require('express-promise-router')();
const VideosController = require('./video.controller');
const { validateParam, validateBody, schemas } = require('../_middleware/routehelpers');
const db = require('../_helpers/db');
const Video = require('./video.model');
const passport = require('passport');
const passportConfig = require('../passport');
const passportLogin = passport.authenticate('local', {session: false});
const passportJwt = passport.authenticate('jwt', { session: false });

const multer = require('multer');
const videoFilter = require('./videoFilter');

// Save file to server storage

 var storage = multer.diskStorage({
        destination: (req, file, cb) => {
          cb(null, './public/videos');
        },
        filename: (req, file, cb) => {
    
           
          
          var filetype = '';
          if (file.mimetype === 'video/gif') {
            filetype = 'gif';
          }
          if (file.mimetype === 'video/mp4') {
            filetype = 'mp4';
          }
          if (file.mimetype === 'video/ogg') {
            filetype = 'ogg';
          }
          if (file.mimetype === 'video/wmv') {
            filetype = 'wmv';
          }
          if (file.mimetype === 'video/x-flv') {
            //filetype = mime.getExtension('video/flv');
            filetype = 'flv';
          }
          if (file.mimetype === 'video/avi') {
            filetype = 'avi';
          }
          if (file.mimetype === 'video/webm') {
            filetype = 'webm';
          }
          if (file.mimetype === 'video/mkv') {
            filetype = 'mkv';
          }
          if (file.mimetype === 'video/avchd') {
            filetype = 'avchd';
          }
          if (file.mimetype === 'video/mov') {
            filetype = 'mov';
          }
          cb(null, 'video-' + Date.now() + '.' + filetype);
        }
      
      });
      
      var upload = multer({ storage: storage, fileFilter: videoFilter.videoFilter });
    

// my routes

router.route('/')
.post(passportJwt,upload.single('file'),VideosController.addNewVideo);

//my controller

 addNewVideo: async (req, res, next) => {       
        // check file for Validation Error
     if (req.fileValidationError) {
         return res.send(req.fileValidationError);
     }
     else if (!req.file) {
         return res.status(500).send({ message: 'Upload fail'});
     } else {
         // if no Validation Error
        // hbjs.spawn({ input: 'something.avi', output: 'something.m4v' })
       // console.log('req.file.filename',req.file.mimetype )
         req.body.videoUrl = 'http://localhost:3000/videos/' + req.file.filename;
 
         //get the body
         const newVideo = req.body;
         //get the user
         const userId = req.user._id;
         //assign new video to the user
         newVideo.userId = userId;
         // create the new video
         const video = await new Video(newVideo);
         // save the new Video
         await video.save();
         //get the user from db
         const user = await db.User.findById(userId);
         // save the new video to user collections
         await user.user_videos.push(video);
         await user.save();
 
         //respond to client
 
         res.status(200).json(video);
        
     }
 },

////// I tested with .flv, the file is saved on the public/videos but I wish to convert all files to popular format only