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Overview

Light and Sound Show is a media-native signed action layer for short-form video. Instead of asking a creator to put a visible QR code on a reel, LSS embeds a compact signed payload into the media itself and lets a reader recover that payload from repeated visual and audio observations.

The production shape is intentionally small: create a signed action, encode it into media with the carrier package, scan carrier evidence back out, verify the recovered protocol envelope, and resolve the action only after verification.

The main path is:

protocol -> carrier encode -> media -> carrier scan -> protocol verify -> resolver

Creator or issuer UI @lss/protocolsign + fragment @lss/carrierencode carrier Tagged MP4 @lss/carrierscan evidence @lss/protocolparse + verify @lss/resolververified action @lss/webUI + policy

Builder map

The docs focus on the packages that sit along that path:

  • @lss/protocol owns canonical payloads, signatures, fragmentation, checksums, and reconstruction data structures.
  • @lss/carrier owns the current media carrier implementation: carrier artifacts, the 24 by 24 visual frame codec, blue-channel visual cell modulation, audio marker/text codecs, browser scan helpers, scan metrics, and Node MP4 carrier helpers.
  • @lss/resolver assumes a signed payload has already been verified, then maps known payload bodies into demo action results.
  • @lss/web wires the packages into creator, scanner, file import, policy, and UI flows.

Two smaller helper packages sit beside the main path:

  • @lss/embedder turns fragment strings into deterministic visual frame plans and ultrasonic tone plans for package-level experiments.
  • @lss/reader provides deterministic simulated read behavior over protocol candidate fragments, useful for reconstruction tests without a real camera, microphone, or MP4 scan.

What LSS protects

LSS protects authenticity, not secrecy. A decoded payload is readable by design. Today, @lss/protocol can verify Ed25519 signatures, reject corrupt fragments by checksum, and reconstruct complete or single-missing-fragment messages with XOR parity. Expiry and issuer policy are carried in the payload, but callers must enforce them before treating a resolver result as trusted.

Best fit

Use LSS when the interaction begins with a video and the action should travel with that video through sharing, replay, projection, or screen recording. Use QR for signage, NFC for tap cards, BLE for nearby radio presence, and watermarking or fingerprinting when identification is more important than carrying an action payload.