Query the player for video metadata.

video-metadata.js

/* Before player load, very basic video metadata is serialized as JSON to a data attribute:

<video
  data-account="2549849259001"
  data-player="d9f2b281-6199-4f8b-821d-ecea1504071f"
  data-embed="default"
  data-video-id="7"
  class="video-js" controls></video>

 You can access any metadata specified this way by querying the DOM:
 */

var account = player.el().getAttribute('data-account');

/* Shortly after a video is loaded into the player, additional metadata will be 
   downloaded. To access this data once it's available, you should listen to 
   `loadedmediainfo`. After that event, metadata for the current video is 
   available on the player itself:
*/
player.on('loadedmediainfo', function() {
  console.log('The video title is: ' + player.mediainfo.title);
});
 
/*
 Information about advertisement configuration can be obtained through the video.js ads 
 plugin (https://github.com/videojs/videojs-contrib-ads). Among many other things, you 
 can find out when ads start and end:
*/

player.on('adstart', function() { console.log('Started an ad pod'); });
player.on('adend', function() { console.log('Finished an ad pod'); });

// If the video changes, the metadata will be updated as well:
player.on('loadedmediainfo', function() {
  sendToAnalytics('new video with metadata:', player.options());
});

// If you'd like to find out at any given moment whether an ad is playing, check the 
// className:
(/ vjs-ad-playing /).test(' ' + player.el().className + ' ');