Send data through the air with sound.

Swift · macOS 13+ and iOS 17+

Add the Swift package

dependencies: [
    .package(
        url: "https://github.com/dweekly/cyrinx.git",
        from: "2.0.0"
    )
],
targets: [
    .target(
        name: "YourApp",
        dependencies: [
            .product(name: "Cyrinx", package: "cyrinx")
        ]
    )
]

Encode and decode a frame

import Cyrinx
import Foundation

let config = BulkPHY.Configuration
    .makePixel7aNearFieldFlagshipProfile(
        amplitude: 0.18
    )
let modem = BulkPHY(configuration: config)
let bytes = modem.geometry()!.payloadBytes
let payload = Data(repeating: 0xA5, count: bytes)

let pcm = modem.encode(payload)! // mono Float, 48 kHz
// Play pcm; record sample-aligned mic channels.
if let result = modem.decode(
        primaryCapture,
        automaticallyCombining: secondaryCapture
    ), result.isComplete {
    let verifiedPayload = result.payload
    // Consume verifiedPayload.
} else {
    // Reject or retry the incomplete frame.
}

The Pixel preset reproduces a measured bench profile; it is not a safe universal default. Validate amplitude, route, and reliability on your own devices. encode accepts exactly one frame of payload.

Portable C

Use the same codec without Swift

The canonical implementation is C. In SwiftPM, add .product(name: "CCyrinx", package: "cyrinx") to a C target and include <cyrinx/cyrinx_bulk.h>. Then fill a cyrinx_bulk_config, compute its geometry, modulate one frame, play and capture audio, then demodulate one or two aligned microphone channels.

1. cyrinx_bulk_compute_geometry
2. cyrinx_bulk_modulate
3. Your 48 kHz playback and capture
4. cyrinx_bulk_demodulate2_auto_v1

Accept the returned payload only when blocks_ok == blocks_total, or use a _with_block_validity entry point to handle blocks individually. Outside SwiftPM, compile cyrinx_bulk.c, cyrinx_fft.c, kiss_fft.c, and kiss_fftr.c with the public and KISS FFT include roots and kiss_fft_scalar=double. The repository does not yet provide CMake, pkg-config, an Android AAR, or JNI bindings.