# Which language-code system applies where: DCNC title-string codes versus CPL metadata tags, and what extra rules does ISDCF Doc 7 add?

- id: art_01M5MRGHXHY1AHB99P7CPN03FG
- 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 · tags: none
- updated: 2026-10-23T16:11:41.356Z
- url: https://veyrul.com/articles/art_01M5MRGHXHY1AHB99P7CPN03FG

Two layers carry language in a DCP: DCNC codes in the title (case carries subtitle-rendering meaning) and BCP 47 tags in CPL metadata, which ISDCF Doc 7 says must be treated case-insensitively; tools converting between them must not copy case semantics across, must keep region subtags (es vs es-419) and should use RFC 4647 matching for playback selection.

Two layers carry language in a DCP: DCNC codes in the title (case carries subtitle-rendering meaning) and BCP 47 tags in CPL metadata, which ISDCF Doc 7 says must be treated case-insensitively; tools converting between them must not copy case semantics across, must keep region subtags (es vs es-419) and should use RFC 4647 matching for playback selection.

Curator qualifications: Registry pages and Doc 7 read 2026-10-22; no DCP built or validated. Doc 7 version/footer date and deferral to the registry from producer reading.

Limitations: Registry pages and Doc 7 read 2026-10-22; no DCP built or validated.

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

```json
{
  "citations": [
    {
      "url": "https://www.isdcf.com/registry/languages/",
      "note": "isdcf.com/registry/languages (live) overview; ISDCF Doc 7 PDF (live) case sensitivity, region subtags, playback"
    },
    {
      "url": "https://files.isdcf.com/papers/ISDCF-Doc7-DigitalCinemaLanguageCodes.pdf",
      "note": "isdcf.com/registry/languages (live) overview; ISDCF Doc 7 PDF (live) case sensitivity, region subtags, playback"
    },
    {
      "url": "https://www.isdcf.com/resources/documents/",
      "note": "isdcf.com/registry/languages (live) overview; ISDCF Doc 7 PDF (live) case sensitivity, region subtags, playback"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Two layers carry language in a DCP: DCNC codes in the title (case carries subtitle-rendering meaning) and BCP 47 tags in CPL metadata, which ISDCF Doc 7 says must be treated case-insensitively; tools converting between them must not copy case semantics across, must keep region subtags (es vs es-419) and should use RFC 4647 matching for playback selection. · locator: isdcf.com/registry/languages (live) overview; ISDCF Doc 7 PDF (live) case sensitivity, region subtags, playback · source: https://www.isdcf.com/registry/languages/

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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