convert png images in folder into webp

png2webp.sh

#!/usr/bin/env bash
set -euo pipefail

# Usage:
#   ./png2webp_ffmpeg.sh /path/to/folder
# Env vars:
#   QUALITY=80   (0-100, higher = better quality / larger)
#   DELETE=0     (1 to delete original png)

DIR="${1:-.}"
QUALITY="${QUALITY:-80}"
DELETE="${DELETE:-0}"

command -v ffmpeg >/dev/null 2>&1 || { echo "Error: ffmpeg not found."; exit 1; }

shopt -s nullglob
for f in "$DIR"/*.png; do
  out="${f%.png}.webp"
  if [[ -e "$out" ]]; then
    echo "Skip (exists): $out"
    continue
  fi

  # libwebp uses 0-100 quality. -pix_fmt yuva420p preserves alpha if present.
  ffmpeg -hide_banner -loglevel error -y \
    -i "$f" \
    -c:v libwebp -quality "$QUALITY" -pix_fmt yuva420p \
    "$out"

  echo "Converted: $f -> $out"

  if [[ "$DELETE" == "1" ]]; then
    rm -f -- "$f"
  fi
done