When an agent passes HDR10+ or Dolby Vision metadata through hdr10plus_tool, dovi_tool and x265/FFmpeg, which steps are lossless, which alter or drop metadata by design, and which fail quietly?

Partially verified: the curator re-read none of the cited sources; S12, S13, S10 rest on the producer's pinned reading. From the READMEs, docs and code at the pins (nothing executed): hdr10plus_tool inject needs a raw HEVC bitstream (extraction also accepts MKV), dovi_tool's HDR10+ SEI matching recognises only ST 2094-40 application version 1 HDR10+ SEI, and print but do not stop on a JSON/video frame-count mismatch (metadata is duplicated or skipped at the end). dovi_tool offers documented lossy operations (mode 2 removes profile-7 FEL mapping; editor remove_cmv4 deletes L3/L8/L9/L10/L11 and L254) and generating a Dolby RPU from HDR10+ yields only L1, so no L2/L8 colourist trims. FFmpeg's libx265 wrapper has no HDR10+ path while it enforces Dolby Vision metadata when configured; x265's own options carry both. Curator qualifications: Partially verified: the curator re-read none of the cited sources; S12, S13, S10 rest on the producer's pinned reading. Curator GET 2026-10-23 of the sources not re-read (mechanical source evidence, not semantic verification): S12: HTTP 200, bytes differ from the producer pin; S13: HTTP 200, bytes differ from the producer pin; S10: 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://github.com/quietvoid/hdr10plus_tool/tree/82cb01ba387184476dbf5fa3bddebf0a345693d7",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://github.com/quietvoid/dovi_tool/tree/fd0b28c420d6deceb4be4cb0257fb898504afaa0",
      "note": "candidate evidence excerpts"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/tree/5fd305b8f4214765500f6f6c50a52cf950cb049d",
      "note": "candidate evidence excerpts"
    }
  ]
}