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RVZSharp Documentation

RVZSharp is a .NET 8 / 9 / 10 library and command-line tool for GameCube and Wii disc images. It reads the modern RVZ container (and its predecessor WIA), decodes the classic legacy formats (GCZ, CISO/WBI, WBFS, TGC, NFS) into a canonical ISO view, and writes RVZ files from any of them — mirroring the behaviour of the reference implementations in Dolphin (C++) and the Go rvz reader.

Target frameworks	net8.0, net9.0, net10.0
Solution file	CSharp_RVZSharp.sln
Tests	313 fast (every framework, ~30 s) + 97 real-file slow tests — the solution runs fast-only by default (dotnet test CSharp_RVZSharp.sln -c Release); run the slow suite explicitly with dotnet test RVZSharp.Slow.Tests -c Release
Read support	RVZ, WIA, GCZ, CISO/WBI, WBFS, TGC, NFS, plain ISO
Write support	RVZ (None, Zstd, Bzip2, LZMA1, LZMA2; optional PRNG-junk packing)
Reference sources	References/dolphin-master/ (C++), References/rvz-1.0.3/ (Go)

Documentation map

Page	What it covers
Getting started	Prerequisites, build, test, first commands
Packaging & distribution	NuGet package contents, build, publish, versioning
CLI reference	info, decode, convert — options and examples
Library API	Blob, RvzReader, RvzWriter, codecs, packing API
Architecture	Module map, read/write pipelines, design decisions
RVZ container format	File head, disc struct, tables, groups, chunking
Compression & packing	Codec details and the Lagged-Fibonacci junk packing
Wii partitions	Encryption, hash tree, hash exceptions, tickets
Legacy formats	GCZ, CISO/WBI, WBFS, TGC, NFS byte layouts
Testing	Test strategy and synthetic image builders
Release notes	1.0.0 announcement content (GitHub release post)
Roadmap & status	Milestones, limitations, open questions
FAQ	Common questions

Conventions used in this wiki

• Byte offsets and sizes are hexadecimal unless stated otherwise (0x…).
• Multi-byte integers are big-endian (network order) unless a page says otherwise.
• The format pages describe the on-disk layout as implemented by Dolphin and verified by this project's tests; they are an implementation companion to References/dolphin-master/docs/WiaAndRvz.md.

Feature overview

• Blob abstraction — every format is opened through the same IBlobReader interface; the format is auto-detected from its magic bytes, so info, decode and convert accept any supported file.
• Canonical ISO view — all readers expose the decoded disc as a random-access stream of ISO bytes, so a GCZ, a WIA and an RVZ of the same disc are interchangeable inputs.
• RVZ writing — the writer stores Wii partition data decrypted with hash exceptions (the same space-saving trick Dolphin uses), detects and packs PRNG junk with a recovered seed, and emits fully checksummed tables (SHA-1 everywhere Dolphin puts them).
• Verifiable — every conversion is byte-exact: the test suite round-trips synthetic discs through every codec, packing setting and chunk size, decodes 30 real GameCube/Wii RVZ files byte-for-byte against their official No-Intro SHA-1s, re-encodes real GC/Wii images back to RVZ, and the CLI can verify decoded output with --sha1.