Preprocess HandiTalk shell

shell.sh

#!/bin/zsh

# Base directory
BASE_DIR="<target>"
CATEGORIES=("Words" "Alphabet")
RESIZED_DIR="Resize"
FRAMES_DIR="Frames"
FRAME_COUNT=8

# Function to resize video and save
resize_video() {
  input_path="$1"
  output_path="$2"
  mkdir -p "$(dirname "$output_path")"
  ffmpeg -i "$input_path" -vf "scale=500:500" "$output_path"
}

# Function to extract frames and save as PNG
extract_frames() {
  input_path="$1"
  output_dir="$2"
  mkdir -p "$output_dir"

  ffmpeg -i "$1" -vf "select=not(mod(n\,5)),scale=250:250" -vsync vfr -vframes $FRAME_COUNT "$output_dir/frame_%04d.png"
}

# Traverse directories and process videos
for category in "${CATEGORIES[@]}"; do
  for class_dir in "$BASE_DIR/$category/Original"/*/; do
    class_name=$(basename "$class_dir")
    for video in "$class_dir"/*.mp4; do
      video_name=$(basename "$video")
      
      # Resize video
      output_resized="$BASE_DIR/$category/$RESIZED_DIR/$class_name/$video_name"
      resize_video "$video" "$output_resized"
      
      # Extract frames
      total_frames=$(ffmpeg -i "$video" -map 0:v:0 -c copy -f null - 2>&1 | grep -oP '(?<=frame=)\s*\d+' | tail -1)
      output_frames="$BASE_DIR/$category/$FRAMES_DIR/$class_name/${video_name%.mp4}"
      extract_frames "$BASE_DIR/$category/$RESIZED_DIR/$class_name/$video_name" "$output_frames"
    done
  done
done