DRS232_LDPC(1)

📦 version 1.0.1, in ubuntu jammy

🌸 DRS232_LDPC(1) — bestie edition 🌸

aka the drs232_ldpc page from the User commands manual — pull up a chair, we're decoding Horus SSTV with the codec2 library and it's honestly iconic 💅

✨ NAME ✨

drs232_ldpc — Horus SSTV reception using the codec2 library. that's it, that's the whole vibe 🛰️💖

🎀 SYNOPSIS 🎀

drs232_ldpc usage: InputOneBitPerChar OutputPacket [-v[v]]

no cap, that's the exact line. copy it, love it, run it 🫶

🦋 DESCRIPTION 🦋

okay so here's the tea ☕: this thing goes hunting for a unique word inside a whole series of soft decision symbols. the moment it finds that UW — found it, periodt — it deframes an RS232-encoded frame made of soft decision bits, runs LDPC decoding on it, and spits out a frame of packed bytes. slay.

and why do we care? because it's used for high bit rate Horus SSTV reception. main character energy fr fr 📡✨

now the frame format, because bestie you need to see this layout:

16 bytes 0x55 - 0xabcdef01 UW - 256 bytes of payload - 2 bytes CRC -
65 bytes LPDC Parity

and every single byte? it gets encoded as a 10 bit RS232 serial word, looking like this:

0 LSB .... MSB 1

that's the whole shape of it. no notes. 👑

💖 OPTIONS 💖

first up, the first argument — InputOneSymbolPerFloat. it's the file name of a file holding the Horus encoded bits. and if you pass - instead? the input comes from stdin. yes queen, pipe it in 🧚

  • InputOneSymbolPerFloat — the file name of a file with Horus encoded bits. give it - and the input is taken from stdin instead.

then the second argument — OutputPackets. it's the file name of a file that gets created, holding modem sample data. pass - here and the output goes to stdout 💫

  • OutputPackets — the file name of a file to be created with modem sample data. give it - and the output is sent to stdout.

and finally, the optional third argument — [-v] or [-vv] — which sets the verbosity of the output. one v for a little chatty, two vs for a lot chatty 🙈

  • -v, -vv — optional, sets the verbosity of the output.
lowkey heads up bestie: the synopsis calls these InputOneBitPerChar and OutputPacket, while the options section says InputOneSymbolPerFloat and OutputPackets. both are exactly as written on the page, so don't come for me, I'm just the messenger 💀

🌈 SEE ALSO 🌈

go read these next, they're the friend group:

and that's the page!! written by drs232_ldpc, dated 2020-12-04 — a whole little time capsule, we love her 🎀 thanks for reading, bestie, go decode something gorgeous 💜✨

📦 where this page comes from