The `DefaultPreloadManager.Builder` is able to build the `DefaultPreloadManager` and `ExoPlayer` instances with the consistently shared configurations. Apps can:
* Simply setup the `DefaultPreloadManager` and `ExoPlayer` with all default configurations via `build()` and `buildExoPlayer()`;
* Or customize the shared configurations by the setters on `DefaultPreloadManager.Builder` and setup via `build()` and `buildExoPlayer()`;
* Or customize the player-only configurations for `ExoPlayer` via `buildExoPlayer(ExoPlayer.Builder)`.
PiperOrigin-RevId: 684852808
`PreloadMediaSource` allows to have a `startPositionUs` passed when `preload` is called, then in `PreloadControl.onContinueLoadingRequested`, it can be more intuitive to see the buffered duration rather than the absolute buffered position as the preload progress. Similar in `DefaultPreloadManager`, we haven't allowed the apps to set a custom start position for individual sources though, once we add this support, using the "duration from the start position" than the absolute position will be less error-prone, otherwise, it can run into a case that the position that the apps set is smaller than the start position.
PiperOrigin-RevId: 674251362
This annotation is only needed on public classes that are part of a
distributed library.
Switch to `@OptIn` for the one file where `@UnstableApi` was
suppressing lint errors.
PiperOrigin-RevId: 633858516
Add a new method `onUsedByPlayer(PreloadMediaSource)` for `PreloadMediaSource.PreloadControl`, which will be invoked when the player starts to use the `PreloadMediaSource`, or calling `PreloadMediaSource.preload` while the player is already using that source. `DefaultPreloadManager` will immediately preload the next source when receiving `onUsedByPlayer` event.
PiperOrigin-RevId: 616789121
Originally a `PlayerId` has to be passed and it should be the same id of the player who is going to play the sources, but it turns out to be unnecessary.
When preloading, we can set a `PlayerId.UNSET` inside of the `PreloadMediaSource`, as there is no ongoing playback. And when the source is handed over to player, player will set the player's `PlayerId`.
PiperOrigin-RevId: 597475119
The `PreloadMediaSource` has below two new public methods that suppose to be called by the app:
* `preload(long)` allows the apps to preload the source at the passed start position before playback. The preload efforts include preparing the source for a `Timeline`, creating and caching a `MediaPeriod`, preparing the period, selecting tracks on the period and continuing loading the data on the period.
* `releasePreloadMediaSource()` allows the apps to release the preloaded progress.
The `PreloadMediaPeriod` is designed to facilitate the `PreloadMediaSource` for the preloading work. It has a new package-private method `selectTracksForPreloading` which will cache the `SampleStream` that corresponds to the track selection made during the preloading, and when the `PreloadMediaPeriod.selectTracks` is called for playback, it will uses the preloaded streams if the new selection is equal to the selection made during the preloading.
Also add a shortform demo module to demo the usage of `PreloadMediaSource` with the short-form content use case.
PiperOrigin-RevId: 574439529
