Running a home theater

The home theater operators turn a machine that is connected to a television into a media player that a household controls with a remote. You declare each room’s screen, speakers, and remote as Kubernetes resources. The operators run the player, keep a catalog of the household’s films and series, and drive the receiver and the television in the room.

For example, a room has a machine connected by HDMI to a receiver and a television, a USB-CEC adapter plugged into a spare input of the receiver, and a Bluetooth remote. With the television in standby, one press of the remote’s power button wakes the television over CEC, switches the television and the receiver to the machine’s input, and turns the receiver on. The media browser shows the namespace’s catalog on the screen, and a press of a button starts a film. When the Catalog names a Jellyfin server, each person’s progress in each title stays the same in Jellyfin and on the television, in both directions.

The operators

media-operator declares a Player for each screen and its speakers, a Play for each title that plays, a Remote for each controller, and a Keymap that maps the buttons of a controller. It runs each Play as one pod with mpv, runs an idle screen while nothing plays, and runs the message bus that connects the remotes, the players, and your own programs. It also measures what each GPU can decode and encode, and publishes the result as devices of its own driver, media.liken.sh.

library-operator declares a Library for each directory of films or series, and scans each one into a Catalog, a SQLite database that Corrosion copies to every screen in the namespace. Its media browser takes the place of a Player’s idle screen and starts a Play on that Player. A MetadataProvider adds titles, plots, and art, which the operator writes as .nfo files and art files beside the media.

people-operator defines the Person resource: one person in the household, with a name and a picture. The media browser asks who is watching. library-operator records those people on each Play, and keeps the progress in each title for them.

equipment-operator controls the A/V equipment that a machine plays through. A Receiver turns an A/V receiver on, selects its input, and sets its volume over the network. A CECBus and a Television wake a TV and put it in standby over HDMI-CEC, through a USB-CEC adapter.

What they depend on

• A Player selects a monitor output from display-operator, an audio output from audio-operator, and a GPU render node from the operating system. A Remote selects a paired controller from bluetooth-operator. You write the device classes they name, as each device operator’s manual shows.
• The capabilities agent of media-operator claims every GPU render node, through the class media-render that it ships.
• equipment-operator claims each USB-CEC adapter that the operating system publishes, through the class cec-adapter that it ships. It reads each Display of display-operator, and a Television reports the Display objects whose picture reaches that TV. It does not connect to the message bus.
• library-operator connects to the message bus of media-operator, so install media-operator first. It reads Player and Person objects, and creates each Play.

Extension points

• The idle screen. A Player’s spec.idle.controller hands the screen to another program while nothing plays. The media browser of library-operator uses this contract, and a program of your own can use it too, as Hand the idle screen to another controller shows.
• The message bus. The bus is MQTT. A program of your own, such as a phone app or a Home Assistant instance, connects as a plain MQTT client with no Kubernetes credentials. It can send commands to a Play, and ask a Player for a volume step or a mute. The bus reference lists each topic and who can write it.
• Play requests. library-operator answers play requests on the bus from any client, so a browser of another make gets the same service.
• The catalog. The catalog is SQLite, and the catalog guide shows how to query it.
• Webhooks. Each Library serves a webhook, so an import in Radarr, Sonarr, or Jellyfin rescans one folder at once.
• The files on the volume. The .nfo files and the art are in the forms that Kodi and Jellyfin read, so those programs can read the same library.
• Jellyfin. spec.jellyfin on a Catalog keeps playback progress the same between library-operator and a Jellyfin server.