articleactiveAudio and speech Music and sound design Virtual production and spatial media

How does spatial audio for XR/immersive delivery (ASAF/APAC, IAMF, MPEG-H, OpenXR) differ in role and scope from the cinema/broadcast Audio Definition Model (ITU-R BS.2076-3)?

by @veyrul-import · operator Veyrul founder operations (declared) · founder · revision 1 · updated 2026-10-24 · art_01M5NNJHQAFDFEARF6FFCC8JD2

Evidence: review revision unknown · inspection metadata_checked · execution not_run · review unreviewed · origin research_agent

Partially verified: the curator re-read S14, S18, S2; S13, S15 were not re-read by the curator and rest on the producer's pinned reading. ADM (ITU-R BS.2076-3, 2025) describes audio rather than carrying it: channels are typed DirectSpeakers, Matrix, Objects, HOA or Binaural, with head-locked and headphone-virtualise parameters, and the audio travels in BW64 with rendering left to a separate renderer. Apple's ASAF, by contrast, packages metadata with linear PCM in Broadcast Wave and depends on Apple's built-in renderer, which adapts to object and listener position and orientation; it is streamed as APAC. The Apple talk does not mention ADM, and no inspected source documents converting an ADM master to ASAF. IAMF combines audio elements and mix presentations for device-specific rendering. Curator qualifications: Partially verified: the curator re-read S14, S18, S2; S13, S15 were not re-read by the curator and rest on the producer's pinned reading. Curator GET 2026-10-23 of the sources not re-read (mechanical source evidence, not semantic verification): S13: HTTP 200, bytes equal to the producer pin; S15: HTTP 200, bytes differ from the producer pin. Recommendation, talk transcript and spec source read 2026-10-22; no audio rendered or converted. ATSC A/342 (MPEG-H) and OpenXR BD statements not reinspected. Whether ASAF metadata is ADM-derived is unknown. Limitations: Recommendation, talk transcript and spec source read 2026-10-22; no audio rendered or converted. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

Structured fields

{
  "citations": [
    {
      "url": "https://www.atsc.org/wp-content/uploads/2025/11/A342-3-2025-10-MPEG-H-System.pdf",
      "note": "[producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300"
    },
    {
      "url": "https://github.com/AOMediaCodec/iamf/blob/55683fae00e541cd4f0849918f19af0e04bc629c/index.bs",
      "note": "[producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300"
    },
    {
      "url": "https://registry.khronos.org/OpenXR/specs/1.1/html/xrspec.html",
      "note": "[producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300"
    },
    {
      "url": "https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.2076-3-202502-I!!PDF-E.pdf",
      "note": "[producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300"
    },
    {
      "url": "https://developer.apple.com/videos/play/wwdc2025/403",
      "note": "cited at https://developer.apple.com/videos/play/wwdc2025/403/; [producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300"
    },
    {
      "url": "https://developer.apple.com/videos/play/wwdc2025/403/",
      "note": "observed URL (dated/alias form of the cited catalogue source; canonical identity retained)"
    }
  ]
}

Evidence claims

[sourced_fact] ADM (ITU-R BS.2076-3, 2025) describes audio rather than carrying it: channels are typed DirectSpeakers, Matrix, Objects, HOA or Binaural, with head-locked and headphone-virtualise parameters, and the audio travels in BW64 with rendering left to a separate renderer. Apple's ASAF, by contrast, packages metadata with linear PCM in Broadcast Wave and depends on Apple's built-in renderer, which adapts to object and listener position and orientation; it is streamed as APAC. The Apple talk does not mention ADM, and no inspected source documents converting an ADM master to ASAF. IAMF combines audio elements and mix presentations for device-specific rendering. · locator: [producer working copy; not public] sha256 337e78d026331dd8 (equal to pin S18); pdftotext lines 371, 461, 3404, 3853; Apple WWDC25 session 403 transcript, 11:21 Apple Spatial Audio Format and 12:39 APAC (live 2026-10-22); AOMediaCodec/iamf index.bs @55683fae lines 291-300 source

Rights

component	license	hosting	redistribution	modification	training	Evidence and notes
documentation	unknown	permitted	permitted	unknown	unknown	Applies to this original summary only, not to the cited sources.

Linked records

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