# What do ITU-R BT.2408 and BT.2390 say about HDR-to-SDR down-mapping, do they cover dynamic metadata, and where is the BT.2390 EETF now?

- id: art_01M5MTX6200QC821QRMW0RQEPF
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T12, T20 · tags: none
- updated: 2026-10-23T16:53:32.346Z
- url: https://veyrul.com/articles/art_01M5MTX6200QC821QRMW0RQEPF

BT.2408-8 section 5.2 says display-light down-mapping is usually preferred, that the monitoring down-mapper must match the one used to make the SDR transmission, and that a plain 0.5 linear scale does not preserve the look on a 100 cd/m2 display. Neither BT.2408-8 nor BT.2390-12 mentions dynamic metadata or trims (keyword counts of 0 for 'dynamic metadata' and '2094'); they are static, display-mapping guidance. The hermite-spline EETF that tools label 'BT.2390' appears in BT.2390 editions -5, -7 and -8 but in this extraction not in -9 to -12; BT.2408-8 Annex 5 carries it. This extends C2-B05-B-08 (BT.2100/2408/2446 reference-white and BT.2446 methods) without repeating it.

BT.2408-8 section 5.2 says display-light down-mapping is usually preferred, that the monitoring down-mapper must match the one used to make the SDR transmission, and that a plain 0.5 linear scale does not preserve the look on a 100 cd/m2 display. Neither BT.2408-8 nor BT.2390-12 mentions dynamic metadata or trims (keyword counts of 0 for 'dynamic metadata' and '2094'); they are static, display-mapping guidance. The hermite-spline EETF that tools label 'BT.2390' appears in BT.2390 editions -5, -7 and -8 but in this extraction not in -9 to -12; BT.2408-8 Annex 5 carries it. This extends C2-B05-B-08 (BT.2100/2408/2446 reference-white and BT.2446 methods) without repeating it.

Curator qualifications: Excerpted evidence located (one excerpt-less row); BT.2408-8 down-mapping guidance; no dynamic-metadata coverage stated.

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

```json
{
  "citations": [
    {
      "url": "https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2408-8-2024-PDF-E.pdf",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2390-8-2020-PDF-E.pdf",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2390-12-2025-PDF-E.pdf",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://github.com/haasn/libplacebo/tree/13d0b79827ea1671f991ca57700e5356af9731a5",
      "note": "candidate evidence excerpts"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] BT.2408-8 section 5.2 says display-light down-mapping is usually preferred, that the monitoring down-mapper must match the one used to make the SDR transmission, and that a plain 0.5 linear scale does not preserve the look on a 100 cd/m2 display. Neither BT.2408-8 nor BT.2390-12 mentions dynamic metadata or trims (keyword counts of 0 for 'dynamic metadata' and '2094'); they are static, display-mapping guidance. The hermite-spline EETF that tools label 'BT.2390' appears in BT.2390 editions -5, -7 and -8 but in this extraction not in -9 to -12; BT.2408-8 Annex 5 carries it. This extends C2-B05-B-08 (BT.2100/2408/2446 reference-white and BT.2446 methods) without repeating it. · locator: candidate evidence excerpts · source: https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2408-8-2024-PDF-E.pdf

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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