Reading the lighting balance score
The Lighting Check measures the average luminance in the left and right halves of your frame every 250 ms using the ITU-R BT.601 luma formula (0.299R + 0.587G + 0.114B) on a downscaled 160×90 copy of your video frame. The balance percentage is the absolute difference between sides divided by the brighter side, expressed as a percentage.
A score below 15% is rated GOOD — both sides of your face receive approximately equal illumination, which appears natural and professional on video calls. Scores between 15–35% earn a WARN rating; at this level, shadowing on one side will be visually noticeable. Above 35% is BAD — expect heavy one-sided shadow that makes video calls look unprofessional.
TIP The most common cause of poor lighting balance is a window directly to one side. Either close the blind or position a secondary lamp on the dark side to act as fill light. A white sheet of paper as a cheap reflector can reduce the balance percentage by 10–20 points.
Understanding face framing and the distance verdicts
The Framing Guide uses MediaPipe's Face Landmarker model (468 3D facial landmarks, ~8 MB WASM bundle loaded from CDN) to locate your face in each video frame. The bounding box, eye midpoint, and face centre are computed from the landmark coordinates and rendered on a canvas overlay that sits on top of the live video.
The distance verdict is based on the width of your face relative to the frame width. A face narrower than 15% of frame width is flagged Too Far; wider than 55% is Too Close. The centre verdict triggers when your face centre deviates more than 25% of the frame width from the horizontal midpoint.
Headroom and the rule of thirds
Headroom is the gap between the top of your head and the top edge of the frame. The headroom guide overlay draws a dashed line at 15% from the top — this is the target upper boundary. With your eyes roughly on the upper third line and 10–20% headroom above your head, you hit the classic broadcast framing standard used in news and professional video calls.
Too much headroom (face positioned low in frame) gives the impression the camera is looking down at you and wastes the most expressive part of the frame. Too little headroom (head cropped at the top) looks unintentionally claustrophobic. The rule-of-thirds grid helps you align your eyes to the upper horizontal third — where viewer attention naturally lands first.
NOTE All face detection runs locally in your browser using a WASM binary and model weights loaded from Google's CDN on first use. Nothing is sent to CapyToolkit servers. The model weights are cached by your browser so subsequent visits load instantly.
Resolution and FPS readout
The Resolution & FPS panel reads live values from your camera's active stream via the MediaStream Track Settings API. The FPS figure is computed from a rolling 10-frame timestamp average rather than the nominal reported framerate — it reflects what the camera is actually delivering to the browser, which may differ from its rated maximum under low-light conditions or when the OS is under load.
Most webcams deliver 30 fps at their native resolution and drop to 15 fps in low light (automatic exposure compensation). The aspect ratio is derived directly from the pixel dimensions — 1920×1080 → 16:9, 1280×800 → 8:5. If you see an unusual ratio, the camera may be delivering a cropped or letterboxed stream rather than its full native sensor area.
Practical steps to improve your lighting balance score
A poor balance score almost always comes from a strong light source directly to one side of your face. A window to the left or right is the most common culprit. Closing that blind partially and positioning a desk lamp or ring light on the shadowed side brings light to the darker half and reduces the imbalance. You do not need studio equipment: a white foam board placed on the darker side reflects the window light back onto your face as fill and can drop a score from 40 percent down to under 20 percent with no additional powered lights at all.
Three-point lighting produces the most consistently professional result for video calls and recordings. Position a key light in front of you and slightly to one side, a fill light on the opposite side at roughly half the key intensity, and a back light behind you at shoulder height to separate your head from the background. Two desk lamps at 45-degree angles in front of you approximate this arrangement without a dedicated lighting kit. Watch the balance percentage update in real time as you adjust each light, and aim for a score below 15 percent before your next call or recording session.
