Hash Lists

Hash files for later verification. Hash lists are generated for successful transfers when verification is enabled and FilmCan can write the list file.

Limitations

Hash lists are stored locally on the destination drive.
If the destination is unavailable, the hash list cannot be re‑verified.

Style: ASC MHL vs Simple

Options › Basic › Hash list style picks the manifest format:

Style	What it writes	For
ASC MHL (default)	Visible `ascmhl/` folder: a per-generation manifest + `ascmhl_chain.xml` (C4 chain of custody)	Delivery-grade, Netflix-conformant
Simple (hidden)	One hidden `.filmcan/hashlists/<roll>.mhl` per roll, no chain	Users who just want verification, clean destination

Resume-skip and verification behave the same either way. The Netflix Ingest preset always forces ASC MHL (the picker is locked).

Format (ASC MHL)

FilmCan writes a spec-faithful ASC MHL v2.0 manifest per roll (xxHash128 / xxh3-128 file hashes), plus an ascmhl_chain.xml index recording each generation by its C4 hash, a chain of custody accepted by the reference ASC MHL tooling.

<hashlist version="2.0" xmlns="urn:ASC:MHL:v2.0">
  <hashes>
    <hash>
      <path size="…">A001C001.mov</path>
      <xxh128 action="original" hashdate="…">…</xxh128>
    </hash>
  </hashes>
</hashlist>

When Generated

The xxHash128 of each file is computed during the copy and written to the manifest as the file finalizes, unless Verification is set to Off. Each backup run adds a new sealed generation to the roll's chain.

Location

ASC MHL, at each roll's ascmhl/ folder (the roll = the source-root folder at the destination):

<destination>/<roll-folder>/ascmhl/0001_<roll>_<date>Z.mhl
<destination>/<roll-folder>/ascmhl/ascmhl_chain.xml

Simple, one hidden file per roll:

<destination>/.filmcan/hashlists/<roll>.mhl

(Backups made before 1.3 used the .filmcan/hashlists/ location for all styles; resume still reads those once.)

Verify Later

Open Transfer History (click the clock icon)
Right-click a transfer
Choose Check data

FilmCan compares files against the saved hashes.

If a transfer is cancelled or fails, or the hash list cannot be written, the list may not be saved.