Display the video

<video id="into-video" class="video-js vjs-default-skin" autoplay controls preload="auto" width="640"
  poster="https://mycdn.cloudfront.net/myposter.png">
   <source src="https://mycdn.cloudfront.net/video.webm" type='video/webm' />
   <source src="https://mycdn.cloudfront.net/video.mp4" type='video/mp4' />
   <p class="vjs-no-js">To view this video please enable JavaScript, or consider upgrading your browser.</p>
</video>

Using VideoJs and ffmpef

# example video encoding for vidoe.js

# for the mp4 video you need aac installed, on Ubuntu:
sudo apt-get install libfaac0

# you seem to need two files for video js, a webm file and an mp4 file
# using ffmpeg these can be generated hence, assuming you start from a .mov file.

ffmpeg -i video.mov -codec:a aac -strict -2 -codec:v h264   -b:a 128k -b:v 1200k -flags +aic+mv4 video.mp4
ffmpeg -i video.mov -codec:a libvorbis      -codec:v libvpx -b:a 128k -b:v 1200k                video.webm