# How does an open head-tracked binaural rendering specification (AOMedia IAMF) express head-locked versus world-locked rendering and reverberant filter profiles, and does it cite or encode the externalization, room-acoustics or latency evidence?

- id: art_01M5MVAFP3NWJQ9PDGYW2424NY
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T10, T13, T19 · tags: none
- updated: 2026-10-23T17:00:48.189Z
- url: https://veyrul.com/articles/art_01M5MVAFP3NWJQ9PDGYW2424NY

The AOMedia IAMF specification at commit 55683fae00e541cd4f0849918f19af0e04bc629c lets an element be rendered head-locked or world-locked when head tracking is enabled, and signals a binaural filter profile of AMBIENT, DIRECT or REVERBERANT. In the text searched (whole index.bs, whitespace-collapsed), the words externalization, HRTF, BRIR and latency do not occur and the profiles carry no stated acoustic parameters, so the specification names the switches that the psychoacoustic evidence is about without citing it or giving values. The mapping to the evidence (world-locked rendering ~ source fixed in the world; REVERBERANT profile ~ reverberant versus anechoic) is a synthesis.

The AOMedia IAMF specification at commit 55683fae00e541cd4f0849918f19af0e04bc629c lets an element be rendered head-locked or world-locked when head tracking is enabled, and signals a binaural filter profile of AMBIENT, DIRECT or REVERBERANT. In the text searched (whole index.bs, whitespace-collapsed), the words externalization, HRTF, BRIR and latency do not occur and the profiles carry no stated acoustic parameters, so the specification names the switches that the psychoacoustic evidence is about without citing it or giving values. The mapping to the evidence (world-locked rendering ~ source fixed in the world; REVERBERANT profile ~ reverberant versus anechoic) is a synthesis.

Curator qualifications: IAMF signals head-locked vs world-locked rendering and a binaural filter profile (AMBIENT/DIRECT/REVERBERANT) but specifies no externalization behaviour; curator readback b0dba1bf.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://github.com/AOMediaCodec/iamf/blob/55683fae00e541cd4f0849918f19af0e04bc629c/index.bs",
      "note": "AOMedia IAMF index.bs at 55683fae L1458-L1498"
    },
    {
      "url": "https://www.ebi.ac.uk/europepmc/webservices/rest/PMC7488874/fullTextXML",
      "note": "AOMedia IAMF index.bs at 55683fae L1458-L1498"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] The AOMedia IAMF specification at commit 55683fae00e541cd4f0849918f19af0e04bc629c lets an element be rendered head-locked or world-locked when head tracking is enabled, and signals a binaural filter profile of AMBIENT, DIRECT or REVERBERANT. In the text searched (whole index.bs, whitespace-collapsed), the words externalization, HRTF, BRIR and latency do not occur and the profiles carry no stated acoustic parameters, so the specification names the switches that the psychoacoustic evidence is about without citing it or giving values. The mapping to the evidence (world-locked rendering ~ source fixed in the world; REVERBERANT profile ~ reverberant versus anechoic) is a synthesis. · locator: AOMedia IAMF index.bs at 55683fae L1458-L1498 · source: https://github.com/AOMediaCodec/iamf/blob/55683fae00e541cd4f0849918f19af0e04bc629c/index.bs

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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