How it works

Finding your place in the film

Boo Cue does not talk to your TV, your streaming service, or your remote. It listens.

When you pick a film, the app downloads an audio fingerprint of it — a compact summary of what that film sounds like, not the audio itself. Once you start, the phone listens through its microphone and matches what it hears against that fingerprint. A match tells it not just that the film is playing but where in it you are, to within a second or so.

From then on the app runs its own clock and re-checks against the room every few seconds. So it keeps up when you pause, when you rewind to catch a line of dialogue, and when someone talks over the film for a minute.

Warning you

Each film has a list of cataloged jump scares with timestamps. As one approaches, Boo Cue warns you — by default about ten seconds ahead, which you can change to anything from five seconds to a minute.

The warning can be a vibration, a line of text on a nearly-black screen, a sound, or any combination. Scares are marked low or high severity, and a high-severity one is underlined. The screen stays dark on purpose: the whole design assumes you are in a dim room, possibly with other people, and that a bright phone is its own kind of ruined scene.

The accessory

There is an optional small device that pairs over Bluetooth. It shows the same countdown as a light, so the phone can stay face down and out of the way.

Two things about it are worth knowing. It receives the film's entire timeline when tracking starts, not scare by scare — so if the phone's battery dies or the app closes, the device keeps counting down on its own. And the phone tells it to stop when the film ends, so it does not sit there glowing at a blank screen.

What it does not do

The audio is never recorded and never uploaded. Matching happens entirely on the phone, against a fingerprint already on the device. There is no recording to send anywhere, and the microphone is released as soon as the film ends or the app stops listening.

There are no accounts. Nothing to sign up for, nothing to log in to.

It does not know what you watch. The app fetches film details and fingerprints from our server, so the server can see that someone asked for a particular film. It is not tied to you, and nothing records a viewing history.

The privacy policy spells all of this out, including the one case where something you typed does leave the device.

The honest limitations

• It only knows films that have been cataloged. If a film has no fingerprint yet, Boo Cue cannot help with it. You can ask for one from the search screen.
• It needs to hear the film. Headphones, a very quiet mix, or a loud conversation over the top will all make matching harder.
• The scare list is made by people, so it reflects a judgment about what counts as a jump scare. A quiet, creeping film may have fewer entries than it felt like it had.
• It warns about jump scares, not about gore, dread, or anything else you might want warning about.