goes-r-emwin-codec

Pure-Python extractor and synthetic encoder for GOES-R EMWIN files — the modern weather data downlink carried inside the HRIT (High Rate Information Transmission) signal on GOES-16 and GOES-18 at 1694.1 MHz. Packaged as a Claude Skill.

This is the file-layer companion to goes-emwin-codec (which handles the legacy GOES-N/O/P 1692.7 MHz BPSK audio format). GOES-R EMWIN doesn't ride on a tractable audio waveform — it's wrapped inside HRIT/CCSDS packets transmitted at ~927 kbps OQPSK, so the realistic input here is file-level: HRIT files coming out of a tool like goestools, or a raw EMWIN packet stream extracted from the HRIT VCID.

What it does

• Decode HRIT files or raw EMWIN packet streams → original NWS files

(text bulletins, GIF/JPG imagery, anything they were carrying)

• Auto-detects which format it's given
• Reassembles multi-part files, including parts split across multiple

input files

• Validates per-packet CRC and end-to-end file CRC
• Encode any file into a synthetic HRIT or raw container for testing

and round-trip verification (not bit-exact to operational HRIT files)

Install (standalone)

No third-party dependencies.

python3 scripts/hrit_emwin_encode.py somefile.png signal.lrit
python3 scripts/hrit_emwin_decode.py signal.lrit --out-dir ./extracted

Install (as a Claude Skill)

Drop the goes-r-emwin.skill zip into your Claude Skills directory or use the "Save skill" install button when Claude offers it. Then ask:

Extract the EMWIN files from these HRIT files. Package this PNG as a synthetic HRIT EMWIN container.

Round-trip self-test

python3 scripts/test_roundtrip.py

Verifies byte-exact recovery for HRIT and raw containers across empty, small, medium, large, compressed, and uncompressed payloads — plus a multi-input reassembly case where one file is split across two input streams.

License

MIT.