How can I play mp4 movie on my ubuntu OS?

I recently downloaded a movie in MP4 format. It is not playing in VLC player. The player shows the message:

You are missing codec pack to play this movie.

I searched for the codec pack but I didn't find any. What should I do to play these type of files on my ubuntu 14.04 LTS?

I have downloaded many packages such as ubuntu-restricted-extras, popcorntime & ffmpeg but none of them works.

This command in a terminal should do:

sudo apt install ubuntu-restricted-extras

(As already explained by David Foerster, but this should be an answer, not a comment.)

Install gstreamer by typing this in terminal:

sudo apt-get install gstreamer1.0-libav

I got success. Hopefully you will. Basically the H.264 plugin is not installed.

VideoLAN VLC is a free video player for Windows and Ubuntu that supports many formats, including MP3s, DVDs, and MP4s.

I'd give that a try and see if it helps you.

Otherwise, you will have to install codecs, as the other answers describe.