header - Header Inspection

Inspect disc image headers, metadata, and compression settings

The header command displays information about disc image files, including game metadata, compression settings, and format-specific details.

Usage

dolphin-tool header [options]

Options

-i FILE, --input=FILE · string · required

Path to the disc image file to inspect.

dolphin-tool header -i game.iso

Supported formats:

• ISO/GCM
• GCZ
• WIA
• RVZ
• WBFS

-j, --json · flag

Output information as JSON format, then exit.

dolphin-tool header -i game.iso --json

Overrides other print options (-b, -c, -l).

-b, --block_size · flag

Print only the block size of GCZ/WIA/RVZ formats, then exit.

dolphin-tool header -i game.rvz --block_size

Output: 131072 (or N/A for formats without block size)

-c, --compression · flag

Print only the compression method of GCZ/WIA/RVZ formats, then exit.

dolphin-tool header -i game.rvz --compression

Output: Zstandard (or N/A for uncompressed formats)

-l, --compression_level · flag

Print only the compression level for WIA/RVZ formats, then exit.

dolphin-tool header -i game.rvz --compression_level

Output: 5 (or N/A for formats without compression levels)

Output Formats

Default Human-Readable Output

Without flags, displays all available information:

dolphin-tool header -i game.rvz

Example output:

Block Size: 131072
Compression Method: Zstandard
Compression Level: 5
Internal Name: Super Smash Bros. Melee
Revision: 2
Game ID: GALE01
Title ID: 0000000000000000
Region: NTSC-U
Country: United States

JSON Output

dolphin-tool header -i game.rvz --json

Example output:

{
  "block_size": 131072,
  "compression_method": "Zstandard",
  "compression_level": 5,
  "internal_name": "Super Smash Bros. Melee",
  "revision": 2,
  "game_id": "GALE01",
  "title_id": 0,
  "region": "NTSC-U",
  "country": "United States"
}

Single Value Output

For scripting, use specific flags:

# Block size
dolphin-tool header -i game.rvz -b
# Output: 131072

# Compression method
dolphin-tool header -i game.rvz -c
# Output: Zstandard

# Compression level
dolphin-tool header -i game.rvz -l
# Output: 5

Information Fields

File Format Information

Block Size

The block size used for compression (GCZ/WIA/RVZ only).

• Measured in bytes
• Common values: 16384, 32768, 65536, 131072, 262144
• Larger blocks = better compression, slower random access

Compression Method

The algorithm used for compression:

• None - Uncompressed (ISO)
• Deflate - GCZ compression
• Bzip2 - Bzip2 compression (WIA/RVZ)
• LZMA - LZMA compression (WIA/RVZ)
• LZMA2 - LZMA2 compression (WIA/RVZ)
• Zstandard - Zstandard compression (RVZ only)
• Purge - Purge mode (WIA only)

Compression Level

The compression level (WIA/RVZ only):

• Range depends on compression method
• Higher = better compression, slower
• WIA/RVZ only; not applicable to GCZ

Game Metadata

Internal Name

The game’s internal title as stored on the disc:

Internal Name: Super Smash Bros. Melee

Game ID

The 6-character game identifier:

Game ID: GALE01

Format: GALE01 where:

• G - Platform (G=GameCube, R=Wii)
• ALE - Game code
• 01 - Region/version

Title ID

The 64-bit title ID (Wii games only):

Title ID: 0001000248414c45

GameCube games show 0.

Revision

The disc revision number:

Revision: 2

Higher numbers indicate later releases.

Region

The disc region:

• NTSC-U - North America
• NTSC-J - Japan
• NTSC-K - South Korea
• PAL - Europe/Australia

Country

Specific country/region:

• United States
• Japan
• Europe
• South Korea
• etc.

Examples

Inspect ISO File

dolphin-tool header -i game.iso

Output:

Internal Name: The Legend of Zelda Twilight Princess
Revision: 0
Game ID: RZDE01
Title ID: 0001000052524445
Region: NTSC-U
Country: United States

Note: No compression information for ISO files.

Inspect RVZ File

dolphin-tool header -i game.rvz

Output:

Block Size: 131072
Compression Method: Zstandard
Compression Level: 5
Internal Name: Mario Kart Wii
Revision: 1
Game ID: RMCE01
Title ID: 0001000052534245
Region: NTSC-U
Country: United States

Get JSON Output

dolphin-tool header -i game.rvz --json

Useful for parsing with jq or other JSON tools:

dolphin-tool header -i game.rvz --json | jq '.game_id'
# Output: "RMCE01"

Check Block Size

dolphin-tool header -i game.rvz -b

Output:

131072

Check Compression Method

dolphin-tool header -i game.rvz -c

Output:

Zstandard

Check Compression Level

dolphin-tool header -i game.rvz -l

Output:

5

Scripting Examples

List All Game IDs

#!/bin/bash

for file in *.{iso,rvz,gcz}; do
  [ -f "$file" ] || continue
  game_id=$(dolphin-tool header -i "$file" --json | jq -r '.game_id')
  echo "$file: $game_id"
done

Check Compression Settings

#!/bin/bash

for rvz in *.rvz; do
  echo "File: $rvz"
  echo "  Block Size: $(dolphin-tool header -i "$rvz" -b)"
  echo "  Compression: $(dolphin-tool header -i "$rvz" -c)"
  echo "  Level: $(dolphin-tool header -i "$rvz" -l)"
done

Identify Game by Title ID

#!/bin/bash

target_id="0001000052534245"  # Mario Kart Wii

for file in *.{iso,rvz}; do
  [ -f "$file" ] || continue
  title_id=$(dolphin-tool header -i "$file" --json | jq -r '.title_id')
  
  if [ "$title_id" = "$target_id" ]; then
    echo "Found: $file"
  fi
done

Generate CSV Database

#!/bin/bash

echo "Filename,Game ID,Internal Name,Region" > games.csv

for file in *.iso; do
  json=$(dolphin-tool header -i "$file" --json)
  filename=$(basename "$file")
  game_id=$(echo "$json" | jq -r '.game_id')
  name=$(echo "$json" | jq -r '.internal_name')
  region=$(echo "$json" | jq -r '.region')
  
  echo "$filename,$game_id,$name,$region" >> games.csv
done

Compare Compression Settings

#!/bin/bash

for file1 in *.rvz; do
  for file2 in *.rvz; do
    [ "$file1" = "$file2" ] && continue
    
    level1=$(dolphin-tool header -i "$file1" -l)
    level2=$(dolphin-tool header -i "$file2" -l)
    
    if [ "$level1" != "$level2" ]; then
      echo "$file1 (level $level1) vs $file2 (level $level2)"
    fi
  done
done

Integration with jq

The JSON output works well with jq for advanced queries:

# Extract specific field
dolphin-tool header -i game.rvz --json | jq '.internal_name'

# Filter by region
for file in *.iso; do
  region=$(dolphin-tool header -i "$file" --json | jq -r '.region')
  if [ "$region" = "NTSC-U" ]; then
    echo "$file is NTSC-U"
  fi
done

# Format custom output
dolphin-tool header -i game.rvz --json | \
  jq -r '"\(.game_id): \(.internal_name) [\(.region)]"'

Use Cases

Identify Unknown Images

Quickly identify what game an image contains:

dolphin-tool header -i unknown.iso

Verify Compression Settings

Check if images are compressed optimally:

for rvz in *.rvz; do
  level=$(dolphin-tool header -i "$rvz" -l)
  if [ "$level" -lt 5 ]; then
    echo "$rvz: Low compression (level $level)"
  fi
done

Organize Game Library

Sort games by region, ID, or name using metadata.

Quality Control

Verify converted images have expected settings:

block_size=$(dolphin-tool header -i game.rvz -b)
if [ "$block_size" != "131072" ]; then
  echo "Warning: Unexpected block size"
fi

Error Messages

”Error: No input set”

Missing -i option. Specify input file:

dolphin-tool header -i game.iso

“Error: Unable to open disc image”

Check:

• File exists and path is correct
• File is a valid disc image
• You have read permissions

Performance

Header inspection is very fast (< 1 second) as it only reads metadata, not the entire file.

See Also

• Verify Command - Verify image integrity
• Convert Command - Format conversion
• DolphinTool Overview - Other utilities