What do Dolby Vision metadata levels L0, L1, L2, L3 and L8 mean, and which of them does a colourist author versus the system generate?

Partially verified: the curator re-read none of the cited sources; S1, S2, S10, S13 rest on the producer's pinned reading. Dolby's own best-practice guide (v4.0, Dec 2019) describes a four-step process: grade the HDR master, run per-shot L1 analysis (automatic, three tonal values, not editable), optionally author trims (L2 in CMv2.9, L8 in CMv4) against named target displays, then deliver. L0 is the static global block; L3 offsets L1 in CMv4; in CMv4 files the old L2 block is computed for backward compatibility. Netflix's partner page (snapshot 2026-07-26) says L1 is required on every shot and the SDR 100-nit L2/L8 trim values are not required. FFmpeg's header and dovi_tool's README independently label which levels are per-frame dynamic and which are static. Curator qualifications: Partially verified: the curator re-read none of the cited sources; S1, S2, S10, S13 rest on the producer's pinned reading. Curator GET 2026-10-23 of the sources not re-read (mechanical source evidence, not semantic verification): S1: HTTP 200, bytes equal to the producer pin; S2: HTTP 200, bytes differ from the producer pin; S10: HTTP 200, bytes differ from the producer pin; S13: HTTP 200, bytes differ from the producer pin. 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/pdfs/dolby_vision_best-practices_colorgrading_v4.pdf",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://partnerhelp.netflixstudios.com/hc/en-us/articles/360058735254-Dolby-Vision-Metadata-Overview",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/tree/5fd305b8f4214765500f6f6c50a52cf950cb049d",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://github.com/quietvoid/dovi_tool/tree/fd0b28c420d6deceb4be4cb0257fb898504afaa0",
      "note": "candidate evidence excerpts"
    }
  ]
}