New properties proposed for live event content

The issue names no repository files or tests. Start by reviewing the BroadcastEvent and SportsEvent definitions and the proposed property types; resolve the open Text-versus-Enumeration choice for programActuality. Done means the proposal has an agreed design and the six vocabulary properties are added with their stated domains and ranges.

The current schema.org vocabulary, while excellent for VOD content, has several gaps that prevent it from being a comprehensive standard for ingesting modern, OTT and broadcast schedules from major content providers.
The core problem we found is that live broadcasts involve multiple layers of timing (e.g., the broadcast window vs. the actual event), complex regional rights and embargoes, and a variety of audio tracks (e.g., home/away commentary) that the current schema does not adequately support.
This proposal introduces a set of new properties, primarily for the BroadcastEvent and SportsEvent types, to address these gaps.

New properties to add to schema.org:

• eventSchedule on type BroadcastEvent Expected type is Schedule
  Distinguishes the precise start and end of the core event (e.g., kick-off to final whistle) from the wider startDate/endDate of the broadcast window (which includes pre/post-show content).
• programActuality on type BroadcastEvent Expected type is either Text or Enumeration (still under discussion)
  A flag to indicate the airing status of the program. Values include Live, Premiere, New, Repeat, and Delayed.
• broadcastImage on type BroadcastEvent Expected type is ImageObject
  Provides a set of images specific to an individual broadcast, allowing for tune-in creative or overlays. This is distinct from the image property of the underlying program.
• audioTrack on type BroadcastEvent Expected type is AudioObject
  A structured object to provide detailed information about an available audio stream, including language, codec, a descriptive name (e.g., "Home Commentary"), and a stream PID.
• regionalAudioPreferences on type BroadcastEvent Expected type is AudioConfiguration
  Defines a different default audio track or an ordered list of fallback preferences for specific geographic regions.
• gameId on type SportsEvent Expected type is Text
  A league-specific, official identifier for a sports game (e.g., an NFL-provided Game ID).