Ad insertion

ExoPlayer can be used for both client-side and server-side ad insertion.

Client-side ad insertion

In client-side ad insertion, the player switches between loading media from different URLs as it transitions between playing content and ads. Information about ads is loaded separately from the media, such as from an XML VAST or VMAP ad tag. This can include ad cue positions relative to the start of the content, the actual ad media URIs and metadata such as whether a given ad is skippable.

When using ExoPlayer’s AdsMediaSource for client-side ad insertion, the player has information about the ads to be played. This has several benefits:

  • The player can expose metadata and functionality relating to ads via its API.
  • ExoPlayer UI components can show markers for ad positions automatically, and change their behavior depending on whether ad is playing.
  • Internally, the player can keep a consistent buffer across transitions between ads and content.

In this setup, the player takes care of switching between ads and content, which means that apps don’t need to take care of controlling multiple separate background/foreground players for ads and content.

When preparing content videos and ad tags for use with client-side ad insertion, ads should ideally be positioned at synchronization samples (keyframes) in the content video so that the player can resume content playback seamlessly.

Declarative ad support

An ad tag URI can be specified when building a MediaItem:

MediaItem mediaItem =
    new MediaItem.Builder().setUri(videoUri).setAdTagUri(adTagUri).build();

To enable player support for media items that specify ad tags, it’s necessary to build and inject a DefaultMediaSourceFactory configured with an AdsLoaderProvider and an AdViewProvider when creating the player:

MediaSourceFactory mediaSourceFactory =
    new DefaultMediaSourceFactory(context)
SimpleExoPlayer player = new SimpleExoPlayer.Builder(context)

Internally, DefaultMediaSourceFactory will wrap the content media source in an AdsMediaSource. The AdsMediaSource will obtain an AdsLoader from the AdsLoaderProvider and use it to insert ads as defined by the media item’s ad tag.

ExoPlayer’s StyledPlayerView and PlayerView UI components both implement AdViewProvider. The IMA extension provides an easy to use AdsLoader, as described below.

Playlists with ads

When playing a playlist with multiple media items, the default behavior is to request the ad tag and store ad playback state once for each media ID and ad tag URI combination. This means that users will see ads for every media item with ads that has a distinct media ID, even if the ad tag URIs match. If a media item is repeated, the user will see the corresponding ads only once (the ad playback state stores whether ads have been played, so they are skipped after their first occurrence).

It’s possible to customize this behavior by passing an opaque ads identifier with which ad playback state for a given media item is linked, based on object equality. Here is an example where ad playback state is linked to the ad tag URI only, rather than the combination of the media ID and ad tag URI, by passing the ad tag URI as the ads identifier. The effect is that ads will load only once and the user will not see ads on the second item when playing the playlist from start to finish.

// Build the media items, passing the same ads identifier for both items,
// which means they share ad playback state so ads play only once.
MediaItem firstItem =
    new MediaItem.Builder()
        .setAdTagUri(adTagUri, /* adsId= */ adTagUri)
MediaItem secondItem =
    new MediaItem.Builder()
        .setAdTagUri(adTagUri, /* adsId= */ adTagUri)

IMA extension

The ExoPlayer IMA extension provides ImaAdsLoader, making it easy to integrate client-side ad insertion into your app. It wraps the functionality of the client-side IMA SDK to support insertion of VAST/VMAP ads. For instructions on how to use the extension, including how to handle backgrounding and resuming playback, please see the README.

The demo application uses the IMA extension, and includes several sample VAST/VMAP ad tags in the sample list.

UI considerations

StyledPlayerView and PlayerView hide controls during playback of ads by default, but apps can toggle this behavior by calling setControllerHideDuringAds, which is defined on both views. The IMA SDK will show additional views on top of the player while an ad is playing (e.g., a ‘more info’ link and a skip button, if applicable).

Since advertisers expect a consistent experience across apps, the IMA SDK does not allow customization of the views that it shows while an ad is playing. It is therefore not possible to remove or reposition the skip button, change the fonts, or make other customizations to the visual appearance of these views.

The IMA SDK may report whether ads are obscured by application provided views rendered on top of the player. Apps that need to overlay views that are essential for controlling playback must register them with the IMA SDK so that they can be omitted from viewability calculations. When using StyledPlayerView or PlayerView as the AdViewProvider, they will automatically register their control overlays. Apps that use a custom player UI must register overlay views by returning them from AdViewProvider.getAdOverlayInfos.

For more information about overlay views, see Open Measurement in the IMA SDK.

Companion ads

Some ad tags contain additional companion ads that can be shown in ‘slots’ in an app UI. These slots can be passed via ImaAdsLoader.Builder.setCompanionAdSlots(slots). For more information see Adding Companion Ads.

Standalone ads

The IMA SDK is designed for inserting ads into media content, not for playing standalone ads by themselves. Hence playback of standalone ads is not supported by the IMA extension. We recommend using the Google Mobile Ads SDK instead for this use case.

Using a third-party ads SDK

If you need to load ads via a third-party ads SDK, it’s worth checking whether it already provides an ExoPlayer integration. If not, implementing a custom AdsLoader that wraps the third-party ads SDK is the recommended approach, since it provides the benefits of AdsMediaSource described above. ImaAdsLoader acts as an example implementation.

Alternatively, you can use ExoPlayer’s playlist support to build a sequence of ads and content clips:

// A pre-roll ad.
MediaItem preRollAd = MediaItem.fromUri(preRollAdUri);
// The start of the content.
MediaItem contentStart =
    new MediaItem.Builder()
// A mid-roll ad.
MediaItem midRollAd = MediaItem.fromUri(midRollAdUri);
// The rest of the content
MediaItem contentEnd =
    new MediaItem.Builder()

// Build the playlist.

Server-side ad insertion

In server-side ad insertion (also called dynamic ad insertion, or DAI), the media stream contains both ads and content. A DASH manifest may point to both content and ad segments, possibly in separate periods. For HLS, see the Apple documentation on incorporating ads into a playlist.

When using server-side ad insertion the client may need to report tracking events to an ad SDK or ad server. For example, the media stream may include timed events that need to be reported by the client (see supported formats for information on what timed metadata formats are supported by ExoPlayer). Apps can listen for timed metadata events from the player, e.g., via SimpleExoPlayer.addMetadataOutput.

The IMA extension currently only handles client-side ad insertion. It does not provide any integration with the DAI part of the IMA SDK.