Fix DASH/SS/HLS module readme files

PiperOrigin-RevId: 329751934

library/dash/README.md

 # ExoPlayer DASH library module #
 # ExoPlayer DASH library module #
 
 
-Provides support for Dynamic Adaptive Streaming over HTTP (DASH) content. To
-play DASH content, instantiate a `DashMediaSource` and pass it to
-`ExoPlayer.prepare`.
+Provides support for Dynamic Adaptive Streaming over HTTP (DASH) content.
+
+Adding a dependency to this module is all that's required to enable playback of
+DASH `MediaItem`s added to an `ExoPlayer` or `SimpleExoPlayer` in their default
+configurations. Internally, `DefaultMediaSourceFactory` will automatically
+detect the presence of the module and convert DASH `MediaItem`s into
+`DashMediaSource` instances for playback.
+
+Similarly, a `DownloadManager` in its default configuration will use
+`DefaultDownloaderFactory`, which will automatically detect the presence of
+the module and build `DashDownloader` instances to download DASH content.
+
+For advanced playback use cases, applications can build `DashMediaSource`
+instances and pass them directly to the player. For advanced download use cases,
+`DashDownloader` can be used directly.
 
 
 ## Links ##
 ## Links ##
 
 

library/hls/README.md

 # ExoPlayer HLS library module #
 # ExoPlayer HLS library module #
 
 
-Provides support for HTTP Live Streaming (HLS) content. To play HLS content,
-instantiate a `HlsMediaSource` and pass it to `ExoPlayer.prepare`.
+Provides support for HTTP Live Streaming (HLS) content.
+
+Adding a dependency to this module is all that's required to enable playback of
+HLS `MediaItem`s added to an `ExoPlayer` or `SimpleExoPlayer` in their default
+configurations. Internally, `DefaultMediaSourceFactory` will automatically
+detect the presence of the module and convert HLS `MediaItem`s into
+`HlsMediaSource` instances for playback.
+
+Similarly, a `DownloadManager` in its default configuration will use
+`DefaultDownloaderFactory`, which will automatically detect the presence of
+the module and build `HlsDownloader` instances to download HLS content.
+
+For advanced playback use cases, applications can build `HlsMediaSource`
+instances and pass them directly to the player. For advanced download use cases,
+`HlsDownloader` can be used directly.
 
 
 ## Links ##
 ## Links ##
 
 

library/smoothstreaming/README.md

 # ExoPlayer SmoothStreaming library module #
 # ExoPlayer SmoothStreaming library module #
 
 
-Provides support for Smooth Streaming content. To play Smooth Streaming content,
-instantiate a `SsMediaSource` and pass it to `ExoPlayer.prepare`.
+Provides support for SmoothStreaming content.
+
+Adding a dependency to this module is all that's required to enable playback of
+SmoothStreaming `MediaItem`s added to an `ExoPlayer` or `SimpleExoPlayer` in
+their default configurations. Internally, `DefaultMediaSourceFactory` will
+automatically detect the presence of the module and convert SmoothStreaming
+`MediaItem`s into `SsMediaSource` instances for playback.
+
+Similarly, a `DownloadManager` in its default configuration will use
+`DefaultDownloaderFactory`, which will automatically detect the presence of
+the module and build `SsDownloader` instances to download SmoothStreaming
+content.
+
+For advanced playback use cases, applications can build `SsMediaSource`
+instances and pass them directly to the player. For advanced download use cases,
+`SsDownloader` can be used directly.
 
 
 ## Links ##
 ## Links ##