FRAMING AND INTEGRITY
Every payload is framed with a header and a CRC, so the receiver knows where a message starts and whether what arrived is what was sent.
06 · OPEN SOURCE
Data over sound.
Encodes a file into a modulated audio waveform, sends it over a channel — a WAV file, a simulated noisy link, or a real speaker-to-microphone path — and decodes a bit-exact copy back out the other side.
# every stage is reversible, and the file that comes back is bit-exact file ─▶ frame (header + CRC) ─▶ Reed–Solomon FEC ─▶ BFSK modulator ─▶ ┐ channel recovered file ◀─ CRC verify ◀─ RS decode ◀─ Goertzel demod + sync ◀─ ┘
The channel can be a WAV file, a simulated link with added noise, or an actual speaker and microphone in the same room.
Every payload is framed with a header and a CRC, so the receiver knows where a message starts and whether what arrived is what was sent.
Forward error correction repairs damage in transit rather than asking for a retransmit — which matters when the channel is a room with a microphone in it.
Binary frequency-shift keying on the way out, Goertzel tone detection and synchronisation on the way back in.
It is a modem, not a network. There is no routing, no addressing and no protocol stack above the frame.
Audio is a slow, noisy channel. This carries small payloads reliably; it is not a way to move your files around.
It is unsigned, so Windows will warn about an unknown publisher. Verify the hash below if that matters to you.
# PowerShell — check the archive against the published hash Get-FileHash .\emcast-1.0.0-win-x64.zip -Algorithm SHA256 # expected: cefac2d7da26d8a0fbfa4d3571265201baf3ca025fd39a30f317782d24d25003
SHA256SUMS.txt covering both platform archives ships with every release.