Force Download MP4 Audio/Video Files using PHP or htaccess

For Membership Video Site, client is looking for Force Download feature for MP4 Audio/Video files. This feature is only for their registered users to download the video files directly to their PC. If you want to implement Force Download feature for MP4 Audio/Video files than it is possible by 2 ways. Force Download MP4 Audio/Video Files using PHP for individual files or Force Download MP4 Audio/Video Files using htaccess for all files.