
The MIME type is currently required to select a SubtitleDecoder implementation in the TextRenderer. Future changes might remove this requirement, so we pre-emptively mark the field as @Nullable. The change in SingleSampleMediaSource ensures the track still maps to the TextRenderer, otherwise it shows up as unmapped. Passing null MIME type to MediaItem.Subtitle constructor now results in this from EventLogger: TextRenderer [ Group:0, adaptive_supported=N/A [ [ ] Track:0, id=null, mimeType=text/x-unknown, language=en, supported=NO_UNSUPPORTED_TYPE ] ] PiperOrigin-RevId: 398010809
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.