SyncDrift timing marks iconSyncDrift: Timecode CheckHelp

Start with paired readings.

  1. Read the reference clock and the other device at the same instant. Know their common frame rate.
  2. Choose New observation run, Import observations CSV or Try the timing study from the library.
  3. Trend shows observed offsets. Readings selects a point, its original values, note and Include in fit switch. Edit changes the note; imported values are read-only. Add a separate manual observation for a correction.
  4. Undo run change and Run actions → Redo run change restore recent changes and survive relaunch. A newly restored JSON run has its own identity and “restored” name.
  5. Files → Prepare run files writes actual files. Preview report opens the PDF. Each named share uses the system sheet. Files are under On My iPhone/iPad → SyncDrift → SyncDrift Exports.

CSV input

Exact header, UTF-8, quoted commas and multiline fields are supported. Maximum 1 MiB and 200 records. Reference readings must strictly advance. Label up to 80 characters, observation note up to 2,000, run note up to 4,000. Day values are 0, 1 or 2.

label,reference,device,reference_day,device_day,note
Start,01:00:00:00,01:00:00:02,0,0,Paired reading

Supported rates: 23.976, 24, 25, 29.97 NDF, 29.97 DF and 30. Use HH:MM:SS:FF; at 29.97 DF a semicolon is also accepted. Invalid frame fields or skipped drop-frame labels are rejected. A smaller clock label never automatically means tomorrow. Paired readings must be within five nominal minutes. Fictional six-reading example.

Interpret the result

Offset is device frame counter minus reference frame counter. Included observations produce a linear least-squares fit against real elapsed hours. Drift is frames per real hour; ppm expresses drift relative to the chosen rational frame rate. Residual is observed minus fitted offset. Excluded observations keep their values and residuals.

Projection is additional drift after the latest included observation, assuming the same trend continues. Horizon accepts 1–24 hours. Tolerance accepts 0.5–100 frames as a reference threshold; it does not certify the device. Two points fit exactly; zero residual does not establish future reliability. No measurement uncertainty is inferred.

Preserve and restore

Run.json includes original CSV bytes, checksums and recent history. Restore creates a separate copy and rejects malformed or checksum-altered data. Invalid imports leave existing saved runs intact. Original imported source rows cannot be deleted or overwritten. In Help and preserved data, raw older archives remain exportable; unreadable saved data is preserved before an explicitly chosen reset.

Derived CSV text is escaped against spreadsheet formula prefixes; original CSV and JSON stay literal. ZIP contains actual outputs and a SHA manifest. PDF reports wrap and paginate text; above 400 pages a PDF-limit explanation replaces the PDF and other complete files remain.

Contact

Email maga40@naver.com with the app version, rate and a minimal reproducible example. Share only files you have permission to share. Do not send sensitive production records unless necessary and authorized. No account, subscription or developer server is required to use the app.