Surface guide
QR codes on tv and broadcast
A QR code on television is scanned from a sofa 2–4 m from the screen, so it needs to occupy 12–20% of the screen height and stay on air for at least 15 seconds. Broadcast compression is the second constraint: fine module detail does not survive it.
| Typical scan distance | 2–4 m |
|---|---|
| Minimum code width | 12–20% of screen height |
| Error correction | M |
Compression eats fine detail
Broadcast and streaming pipelines quantise high-frequency detail — exactly what a QR pattern is. A dense code that looks perfect in the edit softens into mush after encoding.
Defences: keep the payload very short so the version stays low, and preview the code through the actual delivery encode rather than from the master.
Screen size varies enormously
The same broadcast is watched on a 32-inch bedroom set and a 75-inch living-room screen. Size for the smaller one: at least 12% of screen height, and 20% is safer.
Hold time
Fifteen seconds minimum. The viewer has to notice it, find a phone, unlock it and frame the screen. A code flashed for three seconds in a title sequence is decoration.
Motion and safe areas
The code must be static. Any movement, even a slow drift, blurs it for a handheld camera. Keep it inside the title-safe area, and away from any lower-third that might overlay it.
Set-top glare
Glossy screens reflect the room. Placing the code away from the centre, where a viewer's own lamp reflection usually sits, measurably improves read rates.