VFR Gatekeeper
Stop audio drift by quarantining variable-frame-rate clips at ingest
Audio slowly drifts out of sync or randomly desyncs in your timeline when footage is variable frame rate — common with iPhone footage, screen recordings, and some OBS workflows. This recipe catches VFR clips at ingest, transcodes them to constant frame rate, and quarantines the originals so drift never reaches your edit.
INGREDIENTS
PROMPT
Create a skill called "VFR Gatekeeper". Inputs: - ingest_path - quarantine_path - cfr_output_path - target_fps (optional; if not provided, keep nearest stable CFR) - transcode_preset (prores_lt | dnxhr_lb | h264_cfr) Behavior: 1) Watch ingest_path for new media files. 2) For each new file, run ffprobe and determine if the file is likely VFR. 3) If VFR: transcode to CFR into cfr_output_path and write a sidecar JSON mapping (original_path, cfr_path, detected_rates). 4) Move the original to quarantine_path (never delete). 5) Send me a notification summary with paths and next steps for importing into my editor.
How It Works
This skill watches your ingest folder for new media, runs ffprobe to detect variable
frame rate, and automatically transcodes VFR clips to a stable CFR mezzanine. Originals
are moved to a quarantine folder (never deleted), and you get a notification with what
was processed and where to find the clean files.
What You Get
- Automatic VFR detection on every new clip via ffprobe analysis
- CFR transcode to your choice of ProRes 422 LT, DNxHR LB, or H.264 CFR
- Sidecar JSON mapping each original to its CFR replacement
- Originals safely quarantined — never deleted
- Notification summary with paths and next steps for importing into your NLE
Setup Steps
- Set your ingest, quarantine, and CFR output paths
- Choose your transcode preset (ProRes LT, DNxHR LB, or H.264 CFR)
- Optionally set a target FPS (or let it match the nearest stable CFR)
- Run as a watch folder, manual command, or nightly scan
Tips
- Long-form footage (5+ minutes) is where VFR drift hurts most — prioritize those
- Screen recordings and phone footage are the most common VFR culprits
- The sidecar JSON makes it easy to trace any derivative back to its original
- Pair with Proxy Factory for a complete ingest pipeline