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#!/usr/bin/env -S nix shell nixpkgs#parallel nixpkgs#ffmpeg nixpkgs#imagemagick --command bash
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# Define temporary directory variables globally so trap can access them
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# Function to clean up and exit
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echo -e "\nInterrupted. Cleaning up temporary files..."
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# Only remove if directories were actually created
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[ -n "$FRAMES_IN" ] && [ -d "$FRAMES_IN" ] && rm -rf "$FRAMES_IN"
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[ -n "$FRAMES_OUT" ] && [ -d "$FRAMES_OUT" ] && rm -rf "$FRAMES_OUT"
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# Set up trap for Ctrl+C (SIGINT)
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trap cleanup_and_exit INT
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# Check if input and output parameters are provided
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if [ $# -lt 2 ]; then
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echo "Usage: $0 input_video output_video [num_threads]"
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# Default to number of CPU cores if threads not specified
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NUM_THREADS=${3:-$(nproc)}
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# Determine and create temporary directories, preferring RAM disk
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if [ -d "/dev/shm" ] && [ -w "/dev/shm" ]; then
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TEMP_BASE="/dev/shm"
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echo "Using RAM disk (/dev/shm) for temporary files."
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elif [ -d "/tmp" ] && [ -w "/tmp" ] && mount | grep -q 'on /tmp type tmpfs'; then
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echo "Using RAM disk (/tmp) for temporary files."
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echo "RAM disk not available or not writable, using current directory for temporary files."
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# Create unique temporary directory names using process ID
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# Add a random suffix for extra safety in case PID wraps or script runs concurrently
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RAND_SUFFIX=$(head /dev/urandom | tr -dc A-Za-z0-9 | head -c 8)
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FRAMES_IN="${TEMP_BASE}/inkify_frames_in_${$}_${RAND_SUFFIX}"
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FRAMES_OUT="${TEMP_BASE}/inkify_frames_out_${$}_${RAND_SUFFIX}"
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# Check if magick command exists
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if ! command -v magick &>/dev/null; then
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echo "Error: ImageMagick (magick command) not found. Please install it."
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# Attempt cleanup before exiting
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[ -d "$FRAMES_IN" ] && rm -rf "$FRAMES_IN"
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[ -d "$FRAMES_OUT" ] && rm -rf "$FRAMES_OUT"
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# Check if eink-2color.png exists
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if [ ! -f "eink-2color.png" ]; then
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echo "Error: Colormap file 'eink-2color.png' not found in the current directory."
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# Attempt cleanup before exiting
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[ -d "$FRAMES_IN" ] && rm -rf "$FRAMES_IN"
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[ -d "$FRAMES_OUT" ] && rm -rf "$FRAMES_OUT"
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# Create temporary directories only after checks pass
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mkdir -p "$FRAMES_IN"
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if [ $? -ne 0 ]; then echo "Error: Could not create temporary directory $FRAMES_IN"; exit 1; fi
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mkdir -p "$FRAMES_OUT"
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if [ $? -ne 0 ]; then echo "Error: Could not create temporary directory $FRAMES_OUT"; rm -rf "$FRAMES_IN"; exit 1; fi
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# Extract frames from video and detect framerate
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FRAMERATE=$(ffprobe -v error -select_streams v -of default=noprint_wrappers=1:nokey=1 -show_entries stream=r_frame_rate "$INPUT_VIDEO" 2>/dev/null | bc -l | awk '{printf "%.2f", $0}')
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if [ -z "$FRAMERATE" ] || [ "$FRAMERATE" = "0.00" ]; then
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echo "Error: Could not detect framerate for $INPUT_VIDEO."
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cleanup_and_exit # Use cleanup function
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echo "Detected framerate: $FRAMERATE fps"
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# Extract frames from video (use -threads for faster extraction)
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echo "Extracting frames to $FRAMES_IN..."
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if ! ffmpeg -threads "$NUM_THREADS" -i "$INPUT_VIDEO" "$FRAMES_IN/frame_%04d.png" >/dev/null 2>&1; then
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echo "Error: ffmpeg failed to extract frames from $INPUT_VIDEO."
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cleanup_and_exit # Use cleanup function
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# Check if frames were extracted
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if ! ls "$FRAMES_IN"/frame_*.png > /dev/null 2>&1; then
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echo "Error: No frames were extracted to $FRAMES_IN. Check input video and permissions."
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# Process frames in parallel using GNU Parallel
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if command -v parallel &>/dev/null; then
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echo "Processing frames in parallel with $NUM_THREADS threads..."
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# Need to export FRAMES_OUT for parallel to see it in subshells
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# Use parallel's built-in path manipulation {/} for basename
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if ! find "$FRAMES_IN" -name "frame_*.png" | parallel --progress -j "$NUM_THREADS" \
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"magick {} -dither FloydSteinberg -define dither:diffusion-amount=100% -remap eink-2color.png \"$FRAMES_OUT/{/}\""; then
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echo "Error: Parallel processing with magick failed."
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echo "GNU Parallel not found. Processing frames sequentially..."
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# Process each frame with the dithering effect
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for frame in "$FRAMES_IN"/frame_*.png; do
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# Check if the file exists before processing
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if [ -f "$frame" ]; then
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# Construct output path correctly using basename
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output_frame="$FRAMES_OUT/$(basename "$frame")"
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if ! magick "$frame" -dither FloydSteinberg -define dither:diffusion-amount=100% -remap eink-2color.png "$output_frame"; then
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echo "Error: magick failed to process $frame."
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# Decide if you want to stop on first error or continue
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cleanup_and_exit # Stop on first error
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# continue # Or uncomment to continue processing other frames
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# echo "Processed: $frame" # Can be too verbose
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processed_count=$((processed_count + 1))
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echo "Processed $processed_count frames sequentially."
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if [ $processed_count -eq 0 ]; then
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echo "Error: No frames found to process sequentially in $FRAMES_IN"
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# Check if output frames exist before attempting recombination
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if ! ls "$FRAMES_OUT"/frame_*.png > /dev/null 2>&1; then
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echo "Error: No processed frames found in $FRAMES_OUT. Image processing likely failed."
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# Recombine frames into video with detected framerate (use -threads for faster encoding)
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echo "Recombining frames from $FRAMES_OUT..."
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# Allow ffmpeg to prompt for overwrite by removing output redirection
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if ! ffmpeg -framerate "$FRAMERATE" -threads "$NUM_THREADS" -i "$FRAMES_OUT/frame_%04d.png" -c:v libx264 -preset faster -pix_fmt yuv420p "$OUTPUT_VIDEO"; then
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echo "Error: ffmpeg failed to recombine frames into $OUTPUT_VIDEO (or user cancelled overwrite)."
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cleanup_and_exit # Use cleanup function
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# Use the cleanup function for consistency
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cleanup_and_exit() {
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echo -e "\nCleaning up temporary files..."
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# Only remove if directories were actually created
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[ -n "$FRAMES_IN" ] && [ -d "$FRAMES_IN" ] && rm -rf "$FRAMES_IN"
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[ -n "$FRAMES_OUT" ] && [ -d "$FRAMES_OUT" ] && rm -rf "$FRAMES_OUT"
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# Call cleanup explicitly at the end (trap handles interruptions)
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# Reset exit code to 0 for successful completion
dunkirk.sh