PPCP — the PinPoint Capture Protocol. An open protocol for time-synchronised capture devices, its reference implementation, and its conformance suite.
A mobile phone has a 120–240 fps camera, a microphone, an IMU and a hardware encoder. PPCP is how that device — or any other — becomes a first-class capture source for a host that needs to know precisely when each frame was exposed, whether or not a host was present when it was captured.
| Specification | docs/specification/ — PPCP 1.0, APPROVED for implementation (22 August 2026) |
| Wire version | ppcp/1.0 |
| Licence | Specification: open. Library: MIT. |
| Companion spec | PPCP-RV — rendezvous, pairing and the security model. Approved, versioned independently. Implementing it is optional; implementing PPCP is not. |
docs/specification/README.md — what the specification settles, how it got here across four review rounds, and what remains open.
To build and run the conformance suite:
cmake --preset dev && cmake --build --preset dev -j3 && ctest --preset dev
The explicit job count is not decoration. On 22 August 2026 a build launched
with a bare -j alongside two others exhausted memory and took the machine
down; the plan's ground rule 7 now requires every build command to carry one.
Presets are dev (warnings as errors), san (ASan + UBSan), cov (gcov), rel (optimised, keeps debug info) and release (the shipping artefact). swift build builds the same sources as the SwiftPM C target CPPCP. What passes today is recorded in docs/conformance/claim-libppcp.md.
The specification is approved by both first-party implementation teams. It is not yet frozen: ppcp/1.0 becomes stable when the conformance suite passes on both implementations and the interoperability pairings are demonstrated.
| Path | Contents |
|---|---|
docs/specification/ |
The single authority on PPCP. Core model, message catalogue, wire encoding, conformance |
docs/implementation/ |
The implementation plan — work packages across libppcp, PinPointStudio and PinPointCapture, and the session tracker |
docs/conformance/ |
The conformance matrix — every CT-*, RT-* and interoperability row against all three implementations |
include/ppcp/ |
The port surface. ppcp.h is the umbrella. Built: the CBOR codec and framing, the timebase and canonical-instant machinery, the CORE §5 vocabulary, the forty-five-message catalogue, the peer engine, Captures and bulk transfer, the bundle container and its replay onto a live link, clock synchronisation and liveness, Detect/Mint/Arbitrate, and Markup. planned.h is now empty of declarations — every symbol the applications code against has a definition — and stays in the tree for the next package that needs to publish a name ahead of its body |
src/ |
The reference implementation. C11, no dependencies, sans-I/O — no socket, thread, timer, clock or file, asserted at build time by tests/purity.cmake |
tests/ |
The conformance suite. Tests are named after the CT-/RT- row they satisfy |
tools/ |
ppcp-sim and ppcp-conform — the synthetic peer and the conformance driver. Not yet written |