HLS

ExoPlayer supports HLS with multiple container formats. The contained audio and video sample formats must also be supported (see the sample formats section for details). We strongly encourage HLS content producers to generate high quality HLS streams, as described here.

Creating a MediaSource

To play an HLS stream, create an HlsMediaSource and prepare the player with it as usual.

// Create a data source factory.
DataSource.Factory dataSourceFactory =
    new DefaultHttpDataSourceFactory(Util.getUserAgent(context, "app-name"));
// Create a HLS media source pointing to a playlist uri.
HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(uri);
// Create a player instance.
SimpleExoPlayer player = new SimpleExoPlayer.Builder(context).build();
// Prepare the player with the media source.
player.prepare(hlsMediaSource);

The URI passed to HlsMediaSource.Factory.createMediaSource() may point to either a media playlist or a master playlist. If the URI points to a master playlist that declares multiple #EXT-X-STREAM-INF tags then ExoPlayer will automatically adapt between variants, taking into account both available bandwidth and device capabilities.

Accessing the manifest

You can retrieve the current manifest by calling Player.getCurrentManifest. For HLS you should cast the returned object to HlsManifest. The onTimelineChanged callback of Player.EventListener is also called whenever the manifest is loaded. This will happen once for a on-demand content, and possibly many times for live content. The code snippet below shows how an app can do something whenever the manifest is loaded.

player.addListener(
    new Player.EventListener() {
      @Override
      public void onTimelineChanged(
          Timeline timeline, @Player.TimelineChangeReason int reason) {
        Object manifest = player.getCurrentManifest();
        if (manifest != null) {
          HlsManifest hlsManifest = (HlsManifest) manifest;
          // Do something with the manifest.
        }
      }
    });

Customizing HLS playback

ExoPlayer provides multiple ways for you to tailor playback experience to your app’s needs. The following sections briefly document some of the customization options available when building a HlsMediaSource. See the Customization page for more general customization options.

Enabling faster start-up times

You can improve HLS start up times noticeably by enabling chunkless preparation. When you enable chunkless preparation and #EXT-X-STREAM-INF tags contain the CODECS attribute, ExoPlayer will avoid downloading media segments as part of preparation. The following snippet shows how to enable chunkless preparation:

HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(dataSourceFactory)
        .setAllowChunklessPreparation(true)
        .createMediaSource(hlsUri);

You can find more details in our Medium post about chunkless preparation.

Customizing server interactions

Some apps may want to intercept HTTP requests and responses. You may want to inject custom request headers, read the server’s response headers, modify the requests’ URIs, etc. For example, your app may authenticate itself by injecting a token as a header when requesting the media segments.

The following example demonstrates how to implement these behaviors by injecting custom HttpDataSources into an HlsMediaSource:

HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(
            dataType -> {
              HttpDataSource dataSource =
                  new DefaultHttpDataSource(userAgent);
              if (dataType == C.DATA_TYPE_MEDIA) {
                // The data source will be used for fetching media segments. We
                // set a custom authentication request header.
                dataSource.setRequestProperty("Header", "Value");
              }
              return dataSource;
            })
        .createMediaSource(hlsUri);

In the code snippet above, the injected HttpDataSource includes the header "Header: Value" in every HTTP request triggered by hlsMediaSource. This behavior is fixed for every interaction of hlsMediaSource with an HTTP source.

For a more granular approach, you can inject just-in-time behavior using a ResolvingDataSource. The following code snippet shows how to inject request headers just before interacting with an HTTP source:

HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(
        new ResolvingDataSource.Factory(
            new DefaultHttpDataSourceFactory(userAgent),
            // Provide just-in-time request headers.
            (DataSpec dataSpec) ->
                dataSpec.withRequestHeaders(getCustomHeaders(dataSpec.uri))))
        .createMediaSource(customSchemeUri);

You may also use a ResolvingDataSource to perform just-in-time modifications of the URI, as shown in the following snippet:

HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(
        new ResolvingDataSource.Factory(
            new DefaultHttpDataSourceFactory(userAgent),
            // Provide just-in-time URI resolution logic.
            (DataSpec dataSpec) -> dataSpec.withUri(resolveUri(dataSpec.uri))))
        .createMediaSource(customSchemeUri);

Customizing error handling

Implementing a custom LoadErrorHandlingPolicy allows apps to customize the way ExoPlayer reacts to load errors. For example, an app may want fail fast instead of retrying many times, or may want to customize the back-off logic that controls how long the player waits between each retry. The following snippet shows how to implement custom back-off logic when creating a HlsMediaSource:

HlsMediaSource hlsMediaSource =
    new HlsMediaSource.Factory(dataSourceFactory)
        .setLoadErrorHandlingPolicy(
            new DefaultLoadErrorHandlingPolicy() {
              @Override
              public long getRetryDelayMsFor(...) {
                // Implement custom back-off logic here.
              }
            })
        .createMediaSource(hlsUri);

You will find more information in our Medium post about error handling.

Creating high quality HLS content

In order to get the most out of ExoPlayer, there are certain guidelines you can follow to improve your HLS content. Read our Medium post about HLS playback in ExoPlayer for a full explanation. The main points are:

• Use precise segment durations.
• Use a continues media stream; avoid changes in the media structure across segments.
• Use the #EXT-X-INDEPENDENT-SEGMENTS tag.
• Prefer demuxed streams, as opposed to files that include both video and audio.
• Include all information you can in the Master Playlist.

The following guidelines apply specifically for live streams:

• Use the #EXT-X-PROGRAM-DATE-TIME tag.
• Use the #EXT-X-DISCONTINUITY-SEQUENCE tag.
• Provide a long live window. One minute or more is great.

BehindLiveWindowException

In case a live stream with limited availability is played, the player may fall behind this live window if the player is paused or buffering for a long enough period of time. In this case a BehindLiveWindowException is thrown, which can be caught to resume the player at the live edge. The PlayerActivity of the demo app exemplifies this approach.

@Override
public void onPlayerError(ExoPlaybackException e) {
  if (isBehindLiveWindow(e)) {
    // Re-initialize player at the live edge.
  } else {
    // Handle other errors
  }
}

private static boolean isBehindLiveWindow(ExoPlaybackException e) {
  if (e.type != ExoPlaybackException.TYPE_SOURCE) {
    return false;
  }
  Throwable cause = e.getSourceException();
  while (cause != null) {
    if (cause instanceof BehindLiveWindowException) {
      return true;
    }
    cause = cause.getCause();
  }
  return false;
}