Brightcove Player Sample: Chapter Markers in Progress Bar

In this topic, you will learn how to add markers in the progress bar to display defined chapters.

Player example

After starting playback of the video you will see blue markers in the progress bar that indicate the locations of the defined chapters in the video. You can use the chapters icon to jump to chapters and confirm locations.

See the Pen Chapter Markers in Progress Bar by Brightcove Learning Services (@rcrooks1969) on CodePen.

Source code

View the complete solution on GitHub.

Using the CodePen

Here are some tips to effectively use the above CodePen:

  • Toggle the actual display of the player by clicking the Result button.
  • Click the HTML/CSS/JS buttons to display ONE of the code types.
  • Later in this document the logic, flow and styling used in the application will be discussed in the Player/HTML configuration, Application flow and Application styling sections. The best way to follow along with the information in those sections is to:
    1. Click the EDIT ON CODEPEN button in the CodePen and have the code available in one browser/browser tab.
    2. In CodePen, adjust what code you want displayed. You can change the width of different code sections within CodePen.
    3. View the Player/HTML configuration, Application flow and/or Application styling sections in another browser/browser tab. You will now be able to follow the code explanations and at the same time view the code.

Development sequence

Here is the recommended development sequence:

  1. Use the In-Page embed player implementation to test the functionality of your player, plugin and CSS (if CSS is needed)
  2. Put the plugin's JavaScript and CSS into separate files for local testing
  3. Deploy the plugin code and CSS to your server once you have worked out any errors
  4. Use Studio to add the plugin and CSS to your player
  5. Replace the In-Page embed player implementation if you determine that the iframe implementation is a better fit (detailed in next section)

For details about these steps, review the Step-by-Step: Plugin Development guide.

iframe or In-Page embed

When developing enhancements for the Brightcove Player you will need to decide if the code is a best fit for the iframe or In-Page embed implementation. The best practice recommendation is to build a plugin for use with an iframe implementation. The advantages of using the iframe player are:

  • No collisions with existing JavaScript and/or CSS
  • Automatically responsive
  • The iframe eases use in social media apps (or whenever the video will need to "travel" into other apps)

Although integrating the In-Page embed player can be more complex, there are times when you will plan your code around that implementation. To generalize, this approach is best when the containing page needs to communicate to the player. Specifically, here are some examples:

  • Code in the containing page needs to listen for and act on player events
  • The player uses styles from the containing page
  • The iframe will cause app logic to fail, like a redirect from the containing page

Even if your final implementation does not use the iframe code, you can still use the In-Page embed code with a plugin for your JavaScript and a separate file for your CSS. This encapsulates your logic so that you can easily use it in multiple players.

API/Plugin resources used

API Properties

Player/HTML configuration

This section details any special configuration needed during player creation. In addition, other HTML elements that must be added to the page, beyond the in-page embed player implementation code, are described.

Player configuration

No special configuration is required for the Brightcove Player you create for this sample.

Other HTML

No other HTML elements are added to the page.

Application flow

The basic logic behind this application is:

  • Extract the cue points array from the video information.
  • Build an array that contains the start times of all chapters associated with a video.
  • Call a function that makes the marks on the progress bar. You will pass the array of chapter start times along with the video duration.

Retrieve data structure that contains chapter cue points

Find the code which is labeled:

// ### Use the array filter function to retrieve data structure that contains chapter cue points ###

You need to extract the data from the video information that holds the cue points (acting as chapters). You need to use the JavaScript array function filter. Since we do not have an array with which we are interacting, simply use an empty array. Hence the code [].filter. For more information see Array.prototype.filter().

Extract chapter startTimes and store in array

Find the code which is labeled:

// ### Loop over chapter cue points and get start time of each ###

This is fairly straight forward code to loop over the array of cue points and place each cue point's startTime into an array.

Place marks on the progress bar

Find the code which is labeled:

// ### Call function to create marks in progressbar ###

You call the method to place the marks on the progress bar. You pass the chapter's start times array and the video duration. In the function you first get a reference to the progress bar element using JavaScript's document.getElementsByClassName() method. Next you loop over the array of cue points, and for each cue point dynamically create a div, calculate a percentage of where it should be place on the progress bar, then use JavaScript's appendChild() method to place the mark on the progress bar.

Application styling

CSS is used to control the look of the chapter markers:

.vjs-marker {
  position: absolute;
  opacity: 1;
  height: 100%;
  background-color: blue;
  width: 4px;

Plugin code

Normally when converting the JavaScript into a Brightcove Player plugin nominal changes are needed. One required change is to replace the standard use of the ready() method with the code that defines a plugin.

Here is the very commonly used start to JavaScript code that will work with the player:

videojs.getPlayer('myPlayerID').ready(function() {
  var myPlayer = this;

You will change the first line to use the standard syntax to start a Brightcove Player plugin:

videojs.registerPlugin('pluginName', function(options) {
  var myPlayer = this;

As mentioned earlier, you can see the plugin's JavaScript code in this document's corresponding GitHub repo: chapter-markers.js.

Using the plugin with a player

Once you have the plugin's CSS and JavaScript files stored in an Internet accessible location, you can use the plugin with a player. In Studio's PLAYERS module you can choose a player, then in the PLUGINS section add the URLs to the CSS and JavaScript files, and also add the Name and Options, if options are needed.