convert - Format Conversion

Convert GameCube and Wii disc images between different formats

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

Usage

dolphin-tool convert [options]

Options

-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)

-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.

-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.

-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

-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.

-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

-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.

-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.

Examples

Convert ISO to RVZ (Recommended)

Best balance of size and speed:

dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 5

Maximum Compression

For archival purposes:

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

Fast Conversion

Quicker processing with moderate compression:

dolphin-tool convert \
  -i game.iso \
  -o game.rvz \
  -f rvz \
  -b 131072 \
  -c zstd \
  -l 1

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.

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

Legacy GCZ Format

For older Dolphin versions:

dolphin-tool convert \
  -i game.iso \
  -o game.gcz \
  -f gcz \
  -b 16384

WIA Format

Using LZMA2 compression:

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

Compression Comparison

Typical compression ratios for a 4.3 GB Wii game:

Format	Compression	Level	Size	Time
ISO	None	-	4.3 GB	-
GCZ	Deflate	-	2.1 GB	5 min
RVZ	Zstandard	5	1.8 GB	3 min
RVZ	Zstandard	22	1.6 GB	15 min
RVZ	LZMA2	5	1.7 GB	12 min

Times are approximate on modern hardware

Format Recommendations

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

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

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

Warnings and Messages

DolphinTool may display warnings during conversion:

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.

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.

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.

NKit Warning

Warning: Converting an NKit file, output will still be NKit!

NKit images remain in NKit format after conversion. This may affect compatibility.

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.

Error Messages

No input set

Missing -i option. Specify input file:

-i game.iso

No output set

Missing -o option. Specify output file:

-o game.rvz

No output format set

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

Block size must be set for GCZ/RVZ/WIA

Compressed formats require -b option:

-b 131072

Compression method must be set for WIA or RVZ

WIA and RVZ require -c option:

-c zstd

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

Specify -l when using compression:

-l 5

The input file could not be opened

Check:

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

Conversion failed

General failure. Check:

• Sufficient disk space
• Valid input file
• Write permissions for output directory

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

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

See Also

• Verify Command - Verify converted images
• Header Command - Inspect compression settings
• DolphinTool Overview - Other utilities