Format Templates

Customize conversion commands and quality settings for each format group.

Table of Contents

  1. How Format Rules Work
  2. Image Rules
  3. Audio Rules
  4. Video Rules
  5. Example Customizations

How Format Rules Work

Each format group has a rules section with two parts:

  • by_target — Specific commands for a particular target format (takes precedence)
  • default — Fallback command used when no specific command exists
"image_rules": {
    "by_target": {
        "JPEG": "convert '{input}' -quality 90 -strip '{output}'",
        "PNG": "convert '{input}' -depth 8 '{output}'",
        "WEBP": "convert '{input}' -quality 85 -define webp:lossless=false '{output}'"
    },
    "default": "convert '{input}' '{output}'"
}

Image Rules 

"image_rules": {
    "by_target": {
        "JPEG": "convert '{input}' -quality 90 -strip '{output}'",
        "PNG": "convert '{input}' -depth 8 '{output}'",
        "WEBP": "convert '{input}' -quality 85 -define webp:lossless=false '{output}'"
    },
    "default": "convert '{input}' '{output}'"
}

Adjustable parameters:

  • -quality 90 — JPEG quality (1—100, higher = better)
  • -depth 8 — PNG bit depth
  • webp:lossless=false — WEBP compression mode

Audio Rules 

"audio_rules": {
    "by_target": {
        "MP3": "ffmpeg -i '{input}' -codec:a libmp3lame -b:a 192k -y '{output}'",
        "FLAC": "ffmpeg -i '{input}' -codec:a flac -compression_level 5 -y '{output}'",
        "AAC": "ffmpeg -i '{input}' -codec:a aac -b:a 128k -y '{output}'"
    }
}

Adjustable parameters:

  • -b:a 192k — Bitrate (128k, 192k, 256k, 320k)
  • -q:a 2 — Quality level (0—9, lower = better)
  • -compression_level 5 — FLAC compression (0—8)

Video Rules 

"video_rules": {
    "by_target": {
        "MP4": "ffmpeg -i '{input}' -codec:v libx264 -crf 23 -codec:a aac -y '{output}'",
        "MKV": "ffmpeg -i '{input}' -codec:v libx265 -crf 28 -codec:a flac -y '{output}'"
    }
}

Quality parameters:

  • -crf 23 — Constant Rate Factor (18—28, lower = better quality, larger file)
  • -codec:v libx264 — Video codec (h264, h265/hevc, vp9)
  • -codec:a aac — Audio codec

Example Customizations

High-Quality JPEG Conversion:

"JPEG": "convert '{input}' -quality 95 -sampling-factor 4:2:0 -strip '{output}'"

Web-Optimized PNG:

"PNG": "convert '{input}' -depth 8 -colors 256 -strip '{output}'"

High-Quality MP3:

"MP3": "ffmpeg -i '{input}' -codec:a libmp3lame -b:a 320k -y '{output}'"

Fast Video Encoding (lower quality):

"MP4": "ffmpeg -i '{input}' -codec:v libx264 -preset ultrafast -crf 28 '{output}'"