
DownloadHelper is in the ExoPlayer module, so there's no reason why it can't use ExoPlayer specific track selections. That said, we want our UI components to operate on generic TrackSelectionParameters, and we want such UI components to be useful for selecting tracks for download. To keep this interop, it's necessary to have DownloadHelper accept generic TrackSelectionParameters, or to require application code to convert them. The first approach seems preferable! PiperOrigin-RevId: 432158846
ExoPlayer library
The ExoPlayer library is split into multiple modules. See ExoPlayer's top level README for more information about the available library modules and how to use them.