Brightcove Player Sample: Variable Speed Playback

Product(s)
Video Cloud
Brightcove Player
Role(s)
Player Developer
Task(s)
Create & Configure Players
Topic(s)
Playback

In this topic, you will learn how to add a playback rate button to the Brightcove Player control bar, which will allow users to change the video playback speed.

Player example

Start video playback and select the playback rate button in the control bar (default is 1x). Choose a different rate to see how video playback speed changes.

See the Pen eGpMBy by Brightcove Learning Services (@bcls1969) on CodePen.

View the source code.

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 Quick Start: 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 Classes API Methods
ControlBar controlBar.removeChild()
PlaybackRateMenuButton controlBar.addChild()
  controlBar.playbackRateMenuButton.updateLabel()
  controlBar.playbackRateMenuButton.updateVisibility()
  controlBar.playbackRateMenuButton.createMenu()

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

Optional: When you publish your video in Video Cloud Studio's Media module, set the Sizing property to Responsive.

Responsive player setting

Other HTML

Remember to add the id attribute to the video-js tag in the player embed code.

  <video-js id="myPlayerID"
  ...

Application flow

The basic logic behind this application is:

  • Define the playback rates that you want to appear in the playback rate menu.
  • Turn off the default source order for the player.
  • If the playback rate button/menu is already defined in the control bar, then modify it with your defined playback rates.
  • Otherwise, add the playback rate button/menu with your defined playback rates to the control bar.

Define playback rates

Find the code which is labeled:

  // +++ Define the playback rate options +++

Define the playback rates which will be added to the playback rate menu.

Turn off the default source order

Find the code which is labeled:

  // +++ Turn off the default source order +++

Setting sourceOrder to false means that old browsers that support HLS in Flash but not HTML5/MSE will use MP4.

Update the playback rate menu

Find the code which is labeled:

  // +++ Update the existing playback rate menu +++

If the playback rate button/menu exists in the control bar, then update it with your defined playback rates.

Add the playback rate menu

Find the code which is labeled:

  // +++ Add the playback rate menu +++

If it doesn't already exist, add the playback rate button and menu to the control bar.

Support IE browsers

Find the code which is labeled:

  // +++ Support for IE browsers +++

This section of code keeps the selected rate value from resetting to 1x when you pause and play in IE. To test, follow these steps:

  1. Comment out this section of code, and run the sample in an IE 11 browser.
  2. Change the playback rate.
  3. Pause video playback and then restart it.
  4. You will see that the playback rate has been reset to a value of 1x.
  5. Uncomment this section of code and redo the steps above. Now, you should see that the playback rate remains the value that you selected.

Application styling

No additional CSS is needed for this example.

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: variable-speed-playback.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.

After you have added the JavaScript file, add your plugin Name. It should be similar to this:

variableSpeedPlayback

For the plugin options, enter the playback rates that you would like to be displayed in the playback rate menu. It should look similar to this:

{"playbackRates":
  [0.5,1,2]
}