What is Dolby Atmos 'binaural render mode' metadata (Off/Near/Mid/Far) and how does it relate to distance and room feel on headphones?

Problem: control how each bed channel or object sounds on headphones (perceived distance/room). Conditions: Dolby Atmos masters with Dolby AC-4 immersive stereo; documented in the Dolby Atmos Renderer Guide v3.0 (2018, older software). Method: the Renderer supports binaural render mode metadata, a binaural renderer distance model, designed for content encoded as Dolby AC-4 immersive stereo. Per input (bed channel or object) you choose Off (no binaural virtualization), Near, Mid or Far. The metadata is written globally for the whole master, applies to headphone output during monitoring, recording and playback, and is not included with speaker processing. With multiple beds there is only one setting per bed channel (all left channels share a setting). Backwards-compatibility mode deletes bed settings and writes object-only metadata; full edit mode allows per-bed-channel settings but is not backwards compatible for non-AC-4 encodes. Use (inference): choose Near for dialogue-like, close sources, Far for ambience and overheads when the room feel should be larger, and listen on headphones; the guide does not state acoustic parameters for each mode. Room acoustics for AM04-type needs (inference): this is a per-source distance cue, not a room simulation. Failure modes: assuming metadata affects speaker playback; relying on v3.0 behaviour for newer renderers. Limitations: 2018 guide; later versions may differ; no reverb or HRTF details in the text read. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Software version 3.0 (2018); what each mode does acoustically is not defined in the passages read; my placement advice is inference. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://professional.dolby.com/siteassets/content-creation/dolby-atmos/dolby_atmos_renderer_guide.pdf",
      "note": "16 Working with binaural; 22.4.3 Binaural Renderer Mode; 16.1; 16.1"
    }
  ]
}