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Getting Started — Video Replay

The video replay tool plays back a flight by syncing your cockpit video against the matching SD-card log, then overlaying the same M5 indicator your panel showed. Everything runs in the browser; no files are uploaded.

What you need

Three files per flight:

  • Log CSV — the log_NNN.csv written to your SD card.
  • Flight video — a single MP4 / MOV / WebM, or the GoPro chapters (GOPR####.MP4, GP010314.MP4, GP02####.MP4, …) for one recording session.
  • Config CFG — the OnSpeed onspeed2.cfg (XML) that was running on the box at the time of the flight. The flap detents and per-flap setpoints come from here.

Keep one folder per flight on whatever cloud drive you use (Google Drive, Dropbox, OneDrive — all expose normal file system handles to the browser). Put the log, every GoPro chapter, and a copy of the OnSpeed config from your box at the time of the flight all in the same folder. Keep your master config in a separate airframe/ folder; copy it into each flight folder when you archive a flight.

RV-4 Data/
├── airframe/
│   └── onspeed2.cfg          # current/live config — what the box runs
├── 2026-05-11/
│   ├── log_007.csv
│   ├── GOPR0314.MP4
│   ├── GP010314.MP4
│   ├── GP020314.MP4
│   ├── GP030314.MP4
│   └── onspeed2.cfg          # snapshot at flight time
├── 2026-05-25/
│   ├── log_008.csv
│   ├── GOPR0315.MP4
│   └── onspeed2.cfg
└── ...

Conventions the tool relies on (loosely — nothing is enforced):

  • One folder per flight, named by date. Self-evident chronological order in any file browser.
  • A copy of the OnSpeed config inside each flight folder. This is the snapshot. When you re-load a flight months later, walking into the flight folder surfaces the config-as-flown, not whatever the master config has drifted to. Skip this step and the journal still works, but old flights will render under whatever config you pick at re-load time.
  • Master/current config in airframe/. When you update setpoints, this is what you edit on disk and re-upload to the box. After each flight, copy airframe/onspeed2.cfg into the new flight folder.
  • GoPro chapters live alongside the log. The folder-pick flow auto-detects every GOPR#### + GP0N#### sibling.

Loading files

The toolbar has three buttons: Open video…, Open log…, and Open config…. On Chrome / Edge desktop these use the File System Access API — pick a single file, or pick the flight folder and the tool will gather every GoPro chapter automatically. On other browsers the buttons fall back to a plain file-picker (no folder pick, no multi-chapter auto-detect).

When you re-pick the same log later, the takeoff anchor and any clips you saved come back automatically — they're keyed off a hash of the log's first 10 KB, so two flights with different content but the same filename don't collide.

On Chrome / Edge desktop the page also remembers the file handles themselves. Reload within the same browser session and the video, log, and config re-open without a click — a "Resuming…" pill appears in the toolbar while the files load. If the browser has expired the read grant (typical after a browser restart, or after enough time has passed), a Resume banner appears and one click re-grants permission for all three files. Firefox and Safari fall back to the file-picker each session.

Sync

Pick a video and a log; the tool auto-detects takeoff in the log and annotates the timeline. Click Mark video anchor while the video is at the rotation moment, and the two clocks lock. From then on:

  • The flight profile (IAS stripchart at the bottom) is clickable. Click anywhere on it to seek the video to that log moment.
  • Shift-click to manually move the takeoff anchor (useful when the auto-detector picked the wrong climbout, e.g. on a pattern flight with multiple liftoffs).

If sync drifts mid-flight — say a video edit chopped a few seconds out — click Pause indexer for re-sync at a recognizable moment, scrub the video to the matching frame, and click Attach here. The log clock re-anchors against the video at that point.

Ball smoothing slider

Under the mode buttons there's a "Ball smoothing" slider, range 0 to 3 seconds. It only affects the slip ball — the lateral-G EMA time constant for the rendered indicator, NOT the firmware's actual behavior in flight.

  • 0 s — firmware-faithful, lively at 208 Hz.
  • 0.25 s — VN-300 territory.
  • 0.75 s — Dynon SkyView territory.

Dial it up until the ball looks like what you remember seeing on your EFIS in flight. The other channels (AOA, pitch, IAS) are unchanged.

Data marks vs clips

Two granularities of annotation on the same timeline:

  • Data mark (point). The pilot's in-flight button press. The firmware writes a counter into the log's DataMark column; the tool detects each transition and surfaces it as a row in the Data marks panel. You can name a mark, write notes against it, jump the video to it, or kick off a 30 s / 60 s clip starting at it. Marks can't be created in the browser — the firmware owns the DataMark column.
  • Clip (range). A [startLogMs, endLogMs] span you create in the browser. Annotate it, name it, export it as MP4. Clips are independent of marks; a clip that happens to contain marks shows them inline at read time.

Both are stored browser-side, keyed by the log's content hash. Re-load the same log months later, your names and notes come back.

Keyboard shortcuts

The page listens for these keys regardless of which element has focus (typing in an <input> / <textarea> / [contenteditable] passes through normally, so notes and labels are unaffected):

Key Action
Space Play / pause
← or , Step back one frame
→ or . Step forward one frame
Shift + ← / → Step ten frames

Frame size is read from the active video. When the rate can't be detected the tool assumes 30 fps. Stepping while playing pauses first — single frames don't survive an active play loop.