Customizing the UI

Configuring the layout

Once the UI is created, you can pass in configuration options that change the look and functioning of the UI bar. For example, if you wanted to not have a seek bar, you could add the following line to the init() function from the UI basic usage tutorial, after creating the UI overlay:

const video = document.getElementById('video');
const ui = video['ui'];
const config = {
  addSeekBar: false

Controls will fire a shaka.ui.Controls#event:UIUpdatedEvent event once the config takes effect. See the docs for shaka.extern.UIConfiguration for more information.

Customizing the number and order of controls

For example, let's say that all you care about for your app is rewinding and fast-forwarding. You could add the following line to init(), right before creating the UI overlay. This will configure UI to ONLY provide these two buttons:

const config = {
  'controlPanelElements': ['rewind', 'fast_forward']

This call will result in the controls panel having only two elements: rewind button and fast forward button, in that order. If the reversed order is desired, the call should be:

const config = {
 'controlPanelElements': ['fast_forward', 'rewind']

The following elements can be added to the UI bar using this configuration value:

  • time_and_duration: adds an element tracking and displaying current progress of the presentation and the full presentation duration in the "0:10 / 1:00" form where "0:10" (ten seconds) is the number of seconds passed from the start of the presentation and "1:00" (one minute) is the presentation duration.
  • play_pause: adds a button that plays/pauses the video on click.
  • mute: adds a button that mutes/unmutes the video on click.
  • volume: adds a volume slider.
  • fullscreen: adds a button that toggles full screen mode on click.
  • overflow_menu: adds a button that opens an overflow menu with additional settings buttons. It's content is also configurable.
  • rewind: adds a button that rewinds the presentation on click; that is, it starts playing the presentation backwards.
  • fast_forward: adds a button that fast forwards the presentation on click; that is, it starts playing the presentation at an increased speed
  • spacer: adds a chunk of empty space between the adjacent elements.

Similarly, the 'overflowMenuButtons' configuration option can be used to control the contents of the overflow menu. The following buttons can be added to the overflow menu:

  • captions: adds a button that controls the current text track selection (including turning it off). The button is visible only if the content has at least one text track.
  • cast: adds a button that opens a Chromecast dialog. The button is visible only if there is at least one Chromecast device on the same network available for casting.
  • quality: adds a button that controls enabling/disabling of abr and video resolution selection.
  • language: adds a button that controls audio language selection.
  • picture_in_picture: adds a button that enables/disables picture-in-picture mode on browsers that support it. Button is invisible on other browsers.


// Add only the cast button to the overflow menu, nothing else
const config = {
  'overflowMenuButtons' : ['cast']

An important note: the 'overflow_menu' button needs to be part of the 'controlPanelElements' layout for the overflow menu to be available to the user.

The presence of the seek bar and the big play button in the center of the video element can be customized with addSeekBar and addBigPlayButton booleans in the config.

UI layout can be reconfigured at any point after it's been created. Please note that custom layouts might need CSS adjustments to look good.

Changing seek bar progress colors

The seek bar consists of three segments: past (already played part of the presentation), future-buffered and future-unbuffered. To customize the colors, add your values to the config object under seekBarColors:

const config = {
 'seekBarColors': {
   base: 'rgba(255, 255, 255, 0.3)',
   buffered: 'rgba(255, 255, 255, 0.54)',
   played: 'rgb(255, 255, 255)',

If you're using our ad API, you can also specify the color for the ad break markers on the timeline:

const config = {
 'seekBarColors': {
   adBreaks: 'rgb(255, 204, 0)',

Creating custom elements and adding them to the UI

It's possible to add custom application-specific buttons to the UI. Each element has to have it's own class that implements the shaka.extern.IUIElement interface and register with shaka.ui.Controls. All our elements use shaka.ui.Element as a base class. Take a look to see if it's right for your custom buttons.

Let's say, we want to create a button that allows user to skip the currently playing video and go to the next one.

// skipButton.js

// Use shaka.ui.Element as a base class
myapp.SkipButton = class extends shaka.ui.Element {
  constructor(parent, controls) {
    super(parent, controls);

    // The actual button that will be displayed
    this.button_ = document.createElement('button');
    this.button_.textContent = 'Skip current video';

    // Listen for clicks on the button to start the next playback
    this.eventManager.listen(this.button_, 'click', () => {
      const nextManifest = /* Your logic to pick the next video to be played */

      // shaka.ui.Element gives us access to the player object as member of the class

// Factory that will create a button at run time.
myapp.SkipButton.Factory = class {
  create(rootElement, controls) {
    return new myapp.SkipButton(rootElement, controls);

// Register our factory with the controls, so controls can create button instances.
  /* This name will serve as a reference to the button in the UI configuration object */ 'skip',
  new myapp.SkipButton.Factory());

We have our button. Let's see how we can add it to the layout. Similar to specifying the order of shaka-provided controls, we'll need to add a line to the init() function in myapp.js

// This will add three buttons to the controls panel (in that order): shaka-provided
// rewind and fast forward button and out custom skip button, referenced by the name
// we used when registering the factory with the controls.
uiConfig['controlPanelElements'] = ['rewind', 'fast_forward', 'skip'];

Shaka Theme Gallery

Check out the set of [pre-packaged Shaka UI themes][], created by [@lucksy][]! PR contributions to [the gallery repo][] are welcome. [@lucksy]: [pre-packaged Shaka UI themes]: [the gallery repo]:

Continue the Tutorials

Next, check out Creating accessible buttons to make your custom buttons accessible to screen readers.