Stream video back in correct format.

streamDecodedVideo.js

import ffmpeg form 'fluent-ffmpeg';

const filePath = '/Users/yoann/Desktop/video.avi';
const route = (req, res) => {
    res.writeHead(200, getHeaders({'Content-Type': 'video/mp4'}));
    ffmpeg(filePath)
        .format('mp4')
        .addOptions([
            '-movflags frag_keyframe+faststart'
        ])
        .pipe(res, {end: true});
};