Technology transparency

Audio helps SINK find the moment, not identify what you are watching.

SINK rooms already know the selected title. Acoustic fingerprint sync answers a narrower question: where is the viewer in that known timeline? In production phone sync, that comparison happens on the viewer's device.

Viewer sync, step by step

Listen briefly

When a viewer starts phone sync, the production app analyzes a short microphone window on the device.

Compare locally

A covered title's derived reference is downloaded and cached. The viewer's query is compared with it on the phone.

Align the room

A sufficiently supported time offset updates the room clock. Weak or ambiguous evidence should produce no match.

For ordinary production phone sync, raw microphone audio and the phone's derived query fingerprint are not uploaded to SINK. Normal network request metadata can still be processed by SINK's hosting and security providers.

Building public coverage

A signed-in browser-extension user may separately opt in to contribute coverage. The extension processes the active tab's audio locally and uploads derived landmark data with its media position and variant metadata. It does not upload raw tab audio.

Contribution is distinct from phone microphone sync and can be disabled. Public phone sync is offered only after the resolved version has server-verified timeline coverage, at least three independent contributors, and a downloadable catalog. Until then, the app keeps the viewer on Manual.

Authorized private screenings

A screening organizer with the required rights may upload an exact program mix to create a version-specific private fingerprint. The source is used for authorized processing and is not streamed by SINK to attendees.

Private screening artifacts remain isolated from public catalog coverage. Current retention details are published in the privacy policy and may differ when a processing job fails or is cancelled.

What fingerprint sync cannot promise

• Alternate cuts, dubs, leaders, and materially different mixes can require separate coverage.
• Loud rooms, quiet passages, speaker quality, and device differences can prevent a match.
• Off-speed playback and sparse catalog coverage can reduce reliability.
• A fingerprint is derived data, not a guarantee of anonymity or mathematical irreversibility.

See the exact data flow Try the synthetic demo

Implementation summary reviewed August 11, 2026. Claims describe the current production-intended flows and are updated when those flows change.