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The convert command converts disc images between ISO, GCZ, WIA, and RVZ formats with various compression options.

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Usage

dolphin-tool convert [options]

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Options

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-i FILE, --input=FILE
string
required
Path to the source disc image file.
dolphin-tool convert -i game.iso
Supported input formats:
  • ISO/GCM (uncompressed)
  • GCZ (Dolphin compressed)
  • WIA (Wii Image Archive)
  • RVZ (Revolutionary)
  • WBFS (Wii Backup File System)
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-o FILE, --output=FILE
string
required
Path to the destination file.
dolphin-tool convert -i game.iso -o game.rvz
The output extension should match the format specified with -f.
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-f FORMAT, --format=FORMAT
string
default:"rvz"
Container format to use for the output file.
dolphin-tool convert -i game.iso -o game.rvz -f rvz
Available formats:
  • iso - Uncompressed disc image
  • gcz - GameCube compressed format
  • wia - Wii Image Archive
  • rvz - Revolutionary (recommended)
Default is rvz if not specified.
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-b BLOCK_SIZE, --block_size=BLOCK_SIZE
integer
Block size for GCZ/WIA/RVZ formats, in bytes.
dolphin-tool convert -i game.iso -o game.rvz -f rvz -b 131072
Required for GCZ, WIA, and RVZ formats.Recommended values:
  • RVZ: 131072 (128 KiB) - Best balance
  • WIA: 131072 (128 KiB)
  • GCZ: 16384 (16 KiB) - Legacy compatibility
Valid range: Usually 32768 to 2097152 bytes
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-c COMPRESSION, --compression=COMPRESSION
string
Compression method for WIA/RVZ formats.
dolphin-tool convert -i game.iso -o game.rvz -f rvz -c zstd
Required for WIA and RVZ formats.Available methods:
  • none - No compression
  • zstd - Zstandard (RVZ only, recommended)
  • bzip2 - Bzip2 compression
  • lzma - LZMA compression
  • lzma2 - LZMA2 compression
Note: WIA does not support zstd. RVZ does not support purge.
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-l LEVEL, --compression_level=LEVEL
integer
Compression level for the selected method.
dolphin-tool convert -i game.iso -o game.rvz -f rvz -c zstd -l 5
Required when compression is not none.Recommended values for Zstandard:
  • 5 - Good balance (recommended)
  • 1-9 - Fast compression
  • 10-19 - Better compression
  • 20-22 - Maximum compression (slow)
Valid range depends on compression method:
  • Zstandard: 1-22
  • Bzip2: 1-9
  • LZMA/LZMA2: 0-9
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-s, --scrub
flag
Remove junk data during conversion to reduce file size.
dolphin-tool convert -i game.iso -o game.rvz -f rvz -s
Scrubbing:
  • Removes unused data from disc image
  • Reduces file size
  • May not work with all games
  • Warning: RVZ already has excellent compression; scrubbing provides minimal benefit
Only supported for GameCube and Wii disc images. Cannot scrub Datel discs.
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-u USER, --user=USER
string
User folder path for temporary processing files.
dolphin-tool convert -i game.iso -o game.rvz -u /tmp/dolphin
Will be automatically created if not set. Used for temporary data during conversion.

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Examples

Best balance of size and speed: 
dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 5

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Maximum Compression

For archival purposes: 
dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 22

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Fast Conversion

Quicker processing with moderate compression: 
dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 1

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Convert to ISO (Decompress)

Extract to plain ISO format: 
dolphin-tool convert \
  -i game.rvz \
  -o game.iso \
  -f iso
Note: -b, -c, and -l are not needed for ISO output.

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Convert with Scrubbing

Remove junk data while converting: 
dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 5 \
  -s

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Legacy GCZ Format

For older Dolphin versions: 
dolphin-tool convert \
  -i game.iso \
  -o game.gcz \
  -f gcz \
  -b 16384

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WIA Format

Using LZMA2 compression: 
dolphin-tool convert \
  -i game.iso \
  -o game.wia \
  -f wia \
  -b 131072 \
  -c lzma2 \
  -l 5

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Compression Comparison

Typical compression ratios for a 4.3 GB Wii game:
FormatCompressionLevelSizeTime
ISONone-4.3 GB-
GCZDeflate-2.1 GB5 min
RVZZstandard51.8 GB3 min
RVZZstandard221.6 GB15 min
RVZLZMA251.7 GB12 min
Times are approximate on modern hardware

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Format Recommendations

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For General Use: RVZ with Zstandard

-f rvz -b 131072 -c zstd -l 5
Pros:
  • Excellent compression ratio
  • Fast compression/decompression
  • Modern codec
  • Best overall choice

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For Maximum Compatibility: ISO

-f iso
Pros:
  • Works everywhere
  • No decompression overhead
  • Easy to mount/modify
Cons:
  • Very large file size
  • Requires external compression for storage

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For Legacy Systems: GCZ

-f gcz -b 16384
Pros:
  • Compatible with older Dolphin versions
  • Decent compression
Cons:
  • Superseded by RVZ
  • Larger than RVZ
  • Not recommended for new conversions

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Warnings and Messages

DolphinTool may display warnings during conversion:

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Scrubbing RVZ Warning

Warning: Scrubbing an RVZ container does not offer significant space advantages.
RVZ compression is already very efficient. Scrubbing provides minimal additional benefit.

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Scrubbing ISO Warning

Warning: Scrubbing does not save space when converting to ISO unless using external compression.
Scrubbed ISOs are still uncompressed. Use RVZ for better results.

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Wii to GCZ Warning

Warning: Converting Wii disc images to GCZ without scrubbing may not offer space advantages over ISO.
GCZ works best with GameCube games. Use RVZ for Wii games.

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NKit Warning

Warning: Converting an NKit file, output will still be NKit!
NKit images remain in NKit format after conversion. This may affect compatibility.

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Block Size Compatibility

Warning: For GCZs to be compatible with Dolphin < 5.0-11893, the file size must be an integer multiple of the block size...
Older Dolphin versions have stricter GCZ requirements.

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Error Messages

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No input set

Missing -i option. Specify input file: 
-i game.iso

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No output set

Missing -o option. Specify output file: 
-o game.rvz

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No output format set

Missing or invalid -f option. Choose from: iso, gcz, wia, rvz

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Block size must be set for GCZ/RVZ/WIA

Compressed formats require -b option: 
-b 131072

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Compression method must be set for WIA or RVZ

WIA and RVZ require -c option: 
-c zstd

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Compression level must be set when compression type is not ‘none’

Specify -l when using compression: 
-l 5

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The input file could not be opened

Check:
  • File exists
  • File path is correct
  • You have read permissions
  • File is not corrupted

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Conversion failed

General failure. Check:
  • Sufficient disk space
  • Valid input file
  • Write permissions for output directory

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Performance Tips

  1. Use SSD storage - Significantly faster than HDD
  2. Higher compression levels - Slower but smaller files
  3. Larger block sizes - Better compression ratio, slightly slower
  4. Zstandard compression - Best speed/ratio balance

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Batch Conversion Script

Convert all ISOs in a directory: 
#!/bin/bash

INPUT_DIR="./games"
OUTPUT_DIR="./converted"

mkdir -p "$OUTPUT_DIR"

for iso in "$INPUT_DIR"/*.iso; do
  filename=$(basename "$iso" .iso)
  echo "Converting $filename..."
  
  dolphin-tool convert \
    -i "$iso" \
    -o "$OUTPUT_DIR/$filename.rvz" \
    -f rvz \
    -b 131072 \
    -c zstd \
    -l 5
  
  if [ $? -eq 0 ]; then
    echo "✓ Converted $filename"
  else
    echo "✗ Failed: $filename"
  fi
done

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See Also