- Expand instructions.md with step-by-step manual encryption/decryption example using modular addition. - Add padgen.py script to generate random one-time pads from /dev/urandom, formatted in groups. - Add cleanup of temporary audio file in numbers_station.sh. - Minor title update in site/index.html for clarity.
125 lines
4.9 KiB
Bash
Executable File
125 lines
4.9 KiB
Bash
Executable File
#!/bin/bash
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# NERDLETTER NUMBERS STATION MP4 GENERATOR
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# Lincolnshire Poacher style with letter-by-letter cipher readout
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#
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# Audio structure:
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# Base layer (full duration): low-volume shortwave static
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# On top, in sequence:
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# 1. Lincolnshire Poacher theme
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# 2. Voice: announcement + letters (0.5s between letters, 1.0s between groups)
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set -euo pipefail
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SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
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ASSETS_DIR="${SCRIPT_DIR}/../assets"
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MESSAGE="$1" # e.g. "HLXIB JACJP ERXHN EFM"
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PAGE="$2" # e.g. 001
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EPISODE="${3:-01}"
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OUTFILE="nerdletter_secret_${EPISODE}_page${PAGE}.mp4"
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TMPDIR=$(mktemp -d)
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trap 'rm -rf "$TMPDIR"' EXIT
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SAMPLE_RATE=22050
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echo "=== NERDLETTER SECRET TRANSMISSION #${EPISODE} ==="
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echo "Page ${PAGE} — Generating MP4..."
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# --- 1. Generate voice announcement ---
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INTRO_TEXT="NERDLETTER SECRET MESSAGE ${EPISODE}. USE DAY BOOK PAGE ${PAGE}."
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echo "$INTRO_TEXT" | \
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espeak-ng -ven+f3 -s88 -k50 -a 200 -w "${TMPDIR}/intro.wav" --punct="" 2>/dev/null
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# --- 2. Generate letter-by-letter audio with proper gaps ---
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# Build an ffmpeg concat list: each letter as a wav, with silence between
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CONCAT_LIST="${TMPDIR}/concat.txt"
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> "$CONCAT_LIST"
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PART=0
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# Pre-generate silence files
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ffmpeg -f lavfi -i "anullsrc=r=${SAMPLE_RATE}:cl=mono" \
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-t 0.45 -c:a pcm_s16le "${TMPDIR}/gap_letter.wav" -y 2>/dev/null
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ffmpeg -f lavfi -i "anullsrc=r=${SAMPLE_RATE}:cl=mono" \
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-t 0.9 -c:a pcm_s16le "${TMPDIR}/gap_group.wav" -y 2>/dev/null
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for group in $MESSAGE; do
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echo " Group: $group"
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for ((i=0; i<${#group}; i++)); do
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letter="${group:$i:1}"
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PART_FILE="${TMPDIR}/letter_${PART}.wav"
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echo "$letter" | espeak-ng -ven+f3 -s81 -k65 -a 210 -w "$PART_FILE" 2>/dev/null
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echo "file '${PART_FILE}'" >> "$CONCAT_LIST"
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PART=$((PART + 1))
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# 0.5s gap after each letter (except last letter of last group)
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if [ $i -lt $((${#group} - 1)) ]; then
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echo "file '${TMPDIR}/gap_letter.wav'" >> "$CONCAT_LIST"
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fi
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done
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# 1.0s gap after each group
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echo "file '${TMPDIR}/gap_group.wav'" >> "$CONCAT_LIST"
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done
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# Concatenate all letter parts into one track
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ffmpeg -f concat -safe 0 -i "$CONCAT_LIST" \
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-c:a pcm_s16le "${TMPDIR}/letters.wav" -y 2>/dev/null
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# --- 3. Generate closing announcement ---
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OUTRO_TEXT="END TRANSMISSION. TUNE TO OLD COMPUTER NERD DOT COM FOR FURTHER INSTRUCTIONS."
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echo "$OUTRO_TEXT" | \
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espeak-ng -ven+f3 -s88 -k50 -a 200 -w "${TMPDIR}/outro.wav" --punct="" 2>/dev/null
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# --- 4. Concatenate intro + letters + outro ---
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VOICE_LIST="${TMPDIR}/voice_concat.txt"
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echo "file '${TMPDIR}/intro.wav'" > "$VOICE_LIST"
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echo "file '${TMPDIR}/gap_group.wav'" >> "$VOICE_LIST"
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echo "file '${TMPDIR}/letters.wav'" >> "$VOICE_LIST"
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echo "file '${TMPDIR}/gap_group.wav'" >> "$VOICE_LIST"
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echo "file '${TMPDIR}/outro.wav'" >> "$VOICE_LIST"
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ffmpeg -f concat -safe 0 -i "$VOICE_LIST" \
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-ar ${SAMPLE_RATE} -ac 1 -c:a pcm_s16le "${TMPDIR}/voice.wav" -y 2>/dev/null
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# --- 5. Concatenate poacher theme + voice into foreground track ---
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FG_LIST="${TMPDIR}/fg_concat.txt"
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echo "file '${TMPDIR}/poacher_resampled.wav'" > "$FG_LIST"
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echo "file '${TMPDIR}/voice.wav'" >> "$FG_LIST"
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# Resample poacher intro to match
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ffmpeg -i "${ASSETS_DIR}/poacher_intro.wav" \
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-ar ${SAMPLE_RATE} -ac 1 -c:a pcm_s16le "${TMPDIR}/poacher_resampled.wav" -y 2>/dev/null
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ffmpeg -f concat -safe 0 -i "$FG_LIST" \
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-c:a pcm_s16le "${TMPDIR}/foreground.wav" -y 2>/dev/null
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# --- 6. Get foreground duration, generate static to match ---
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FG_DUR=$(ffprobe -v quiet -show_entries format=duration -of csv=p=0 "${TMPDIR}/foreground.wav")
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echo " Audio duration: ${FG_DUR}s"
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ffmpeg -f lavfi -i "anoisesrc=d=${FG_DUR}:c=0.22" \
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-af "highpass=f=2500,lowpass=f=9000,volume=0.18" \
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-ar ${SAMPLE_RATE} -ac 1 -t "${FG_DUR}" \
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-c:a pcm_s16le "${TMPDIR}/static.wav" -y 2>/dev/null
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# --- 7. Mix static underneath foreground ---
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ffmpeg -i "${TMPDIR}/foreground.wav" -i "${TMPDIR}/static.wav" \
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-filter_complex "[0:a][1:a]amix=inputs=2:duration=longest:normalize=0" \
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-c:a pcm_s16le "${TMPDIR}/final_audio.wav" -y 2>/dev/null
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# --- 8. Build video to match audio duration ---
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# Round up to nearest second for video duration
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VIDEO_DUR=$(echo "$FG_DUR" | awk '{printf "%d", $1 + 1}')
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ffmpeg -f lavfi -i "color=black:s=1280x720:d=${VIDEO_DUR}" \
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-i "${TMPDIR}/final_audio.wav" \
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-vf "drawtext=font='Courier':fontsize=50:fontcolor=green@0.95:text='NERDLETTER SECRET TRANSMISSION #${EPISODE}':x=(w-text_w)/2:y=80, \
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drawtext=font='Courier':fontsize=36:fontcolor=green@0.85:text='USE DAY BOOK PAGE ${PAGE}':x=(w-text_w)/2:y=170, \
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drawtext=font='Courier':fontsize=44:fontcolor=lime@0.95:text='${MESSAGE}':x=(w-text_w)/2:y=270:box=1:boxcolor=black@0.75:boxborderw=15, \
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drawtext=font='Courier':fontsize=30:fontcolor=green@0.75:text='DESTROY PAGE AFTER USE — SUBSCRIBERS ONLY':x=(w-text_w)/2:y=640" \
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-c:v libx264 -pix_fmt yuv420p -c:a aac -shortest "$OUTFILE" -y
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rm "${TMPDIR}/final_audio.wav"
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echo "Done: ${OUTFILE}"
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