Massekonvertering af billeder med FFmpeg: en praktisk guide

# macOS
brew install ffmpeg

# Ubuntu / Debian
sudo apt install ffmpeg

# Windows (Chocolatey)
choco install ffmpeg

ffmpeg -version

mkdir -p output
for f in *.png; do
  ffmpeg -i "$f" -q:v 2 "output/${f%.png}.jpg"
done

mkdir output
for %f in (*.png) do ffmpeg -i "%f" -q:v 2 "output/%~nf.jpg"

New-Item -ItemType Directory -Force output
Get-ChildItem *.png | ForEach-Object {
  ffmpeg -i $_.FullName -q:v 2 "output/$($_.BaseName).jpg"
}

mkdir -p output
for f in *.jpg *.jpeg; do
  [ -f "$f" ] || continue
  ffmpeg -i "$f" -quality 85 "output/${f%.*}.webp"
done

mkdir -p output
for f in *.png; do
  ffmpeg -i "$f" -lossless 1 "output/${f%.png}.webp"
done

mkdir -p output
for f in *.jpg *.jpeg; do
  [ -f "$f" ] || continue
  ffmpeg -i "$f" "output/${f%.*}.png"
done

mkdir -p output
for f in *.jpg *.jpeg *.png *.webp *.tiff *.bmp; do
  [ -f "$f" ] || continue
  ffmpeg -i "$f" -q:v 3 "output/${f%.*}.jpg"
done

mkdir -p output
for f in *.png; do
  ffmpeg -i "$f" -vf scale=1080:-1 -q:v 3 "output/${f%.png}.jpg"
done

mkdir -p output
for f in *.jpg; do
  ffmpeg -i "$f" -vf "crop='min(iw,ih)':'min(iw,ih)',scale=200:200" \
    "output/${f%.jpg}_thumb.jpg"
done

find . -name "*.png" -not -path "./output*" | while read f; do
  output="output/${f#./}"
  mkdir -p "$(dirname "$output")"
  ffmpeg -i "$f" -q:v 3 "${output%.png}.jpg"
done

mkdir -p output
ls *.png | xargs -P 4 -I {} sh -c 'ffmpeg -i "$1" -q:v 3 "output/${1%.png}.jpg"' _ {}

total=$(ls *.png | wc -l)
count=0
mkdir -p output
for f in *.png; do
  count=$((count + 1))
  echo "[$count/$total] $f"
  ffmpeg -loglevel quiet -i "$f" -q:v 3 "output/${f%.png}.jpg"
done

mkdir -p output
error_log="errors.txt"
> "$error_log"
for f in *.jpg *.jpeg *.png *.webp; do
  [ -f "$f" ] || continue
  if ffmpeg -loglevel error -i "$f" -quality 85 "output/${f%.*}.webp" 2>>"$error_log"; then
    echo "✓ $f"
  else
    echo "✗ $f"
  fi
done