46 lines
2.4 KiB
Markdown
46 lines
2.4 KiB
Markdown
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# CLAUDE.md
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This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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## Project Overview
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Nerdletter Cypher is a collection of bash scripts that generate "numbers station" style MP4 videos for the Nerdletter newsletter. Each video displays a ciphertext message with retro green-on-black terminal aesthetics and a synthesized voice reading the message aloud, mimicking cold-war shortwave numbers stations (specifically the Lincolnshire Poacher style).
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Subscribers use a "Day Book" (a one-time pad or codebook) to decode the ciphertext messages.
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## Script Variants
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All scripts live in `scripts/` and share a common interface:
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```bash
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./script.sh "CIPHERTEXT GROUPS" PAGE_NUMBER [EPISODE_NUMBER]
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# Example: ./script.sh "HLXIB JACJP ERXHN EFM" 001 01
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```
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- **nerdletter_numbers_station.sh** — Original basic version (espeak-ng + ffmpeg, single pass)
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- **nerdletter_numbers_station_linux.sh** — Linux variant with letter-by-letter pronunciation
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- **nerdletter_numbers_station_mac.sh** / **_mac_old.sh** — macOS variants (uses `Courier New` font for Homebrew ffmpeg compatibility)
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- **nerdletter_numbers_station_poacher.sh** through **poacher10.sh** — Iterative refinements adding: Lincolnshire Poacher intro music, shortwave static mixing, letter-by-letter speech with inter-group pauses, longer durations, and audio layering
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The `poacher` series represents progressive iterations. The highest-numbered poacher script (`poacher10.sh`) is the most refined version with letter-by-letter speech, pauses between cipher groups, and full audio mixing (poacher intro + static + voice).
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## Dependencies
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- **espeak-ng** — text-to-speech synthesis (voice: `en+f3`, female)
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- **ffmpeg** — video generation, audio mixing, and final MP4 encoding
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- **wget** — (poacher scripts only) for downloading the Lincolnshire Poacher intro audio from archive.org
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## Assets
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- `assets/poacher_intro.wav` — Lincolnshire Poacher music intro clip
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- `assets/static.wav` — Shortwave radio static noise
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- `output/` — Generated MP4 files land here (though some scripts output to the current working directory)
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## Key Parameters Across Scripts
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espeak-ng flags control the voice character:
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- `-s` speech rate (lower = slower/more dramatic, ranges from 74-120 across variants)
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- `-k` capitals emphasis
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- `-a` amplitude/volume
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- `-ven+f3` English female voice variant 3
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