Details on settings available in Media Player are below.
View Type: Choose between viewing files in a list or grid.
Show Fanart: Fanart can be shown as a backdrop for the pre-playback screen (available when using Grid View).
Show File Extensions: Show or hide your files' extensions (I.E. Yes = 'MyMovie.mkv' vs No = 'MyMovie')
Show Local Files: Enable local files to browse and play content that is stored locally on the Apple TV.
Watched Indicators: Choose whether or not to show watched status indicators.
Sort By: Sort files by name or date.
Metadata Fetching: Enable metadata fetching to have Media Player automatically download information and cover art for Movies and TV Shows.
File Management: When enabled, allows files to be deleted from the Apple TV (Note: Requires read/write access on the source device)
Media Shelf: Display Recently Watched or Recently Added movies/shows in the main menu.
Last.fm: Setup Last.fm audio track scrobbling.
trakt.tv: Setup trakt.tv video scrobbling and syncing.
Zoom Mode: Adjust the default zoom mode for videos.
Show Subtitles: When set to Yes, subtitles will be shown by default (if available). Subtitles can always be enabled/disabled on a per file basis through the Playback Menu (hold select while a video is playing).
Playlist Type: Options for video playlists
Dolby Digital (AC3) Audio: Enable AC3 sound from files that contain an AC3 audio track (requires an AC3 compatible receiver).
DTS Audio: Enable DTS sound from files that contain a DTS audio track (requires a DTS compatible receiver).
Volume Control: Allows for volume to be controlled using the UP/DOWN arrows while a video is playing in Media Player. If disabled, the UP/DOWN arrows will be used to toggle chapter controls.
Center Channel Boost: Allows for enhance dialogue audio track (works well when watching videos at low volume).
Track Info: Allows Media Player to automatically download and display artist bio and track info while music is being played.
Slideshow Timeout: Adjust the time before an artist slideshow automatically starts while music is being played.
Playlist Type: Options for music playlists
Clear Recently Watched: Remove the recently watched items from the 'Top Shelf' area of the Media menu.
Clear All Metadata: Remove all metadata that has been downloaded for your files.