Formats Comparison and Specifications

Supported Formats, Technical Specifications & Emulators

XGDTool provides complete, bidirectional conversion between raw disc dumps, scrubbed images, emulator-optimized compressed archives, and original hardware containers.

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Formats Comparison Matrix

Format	File Extension	Compression Algorithm	Primary Use Case	Target Hardware / Emulator	Average Size (8 GB Disc)
ISO / XISO	.iso	None (Uncompressed)	Burning to DVD+R DL or raw backup	Original Xbox, Xbox 360 (Optical Drive), Xemu, Xenia	~7.29 GB (XGD2) / ~8.13 GB (XGD3) / Scrubbed ~1–6 GB
CSO	.cso	LZ4 (Fast, Block-based)	High-speed emulator storage	Xbox Emulators (Xemu), Custom Tools	~2.5 – 5.5 GB
CCI	.cci	LZ4 (Chunk-based)	High-speed compressed Xbox image	Original Xbox Emulators	~2.5 – 5.5 GB
GoD	Container folder (00007000)	Proprietary Hash Chunks	Direct USB/HDD execution without disc	Xbox 360 RGH/JTAG, Aurora, FreestyleDash, Xenia	~2.0 – 6.5 GB (only actual data sectors stored)
ZAR	.zar	Zstandard (Zstd Levels 1–6)	Ultra-compact archive with fast random read	Cemu, Specialized Emulators, Cold Storage	~1.5 – 4.5 GB
Folder (Extract)	Directory of loose files	None	Modding, asset replacement, homebrew	Xbox 360 Aurora, Original Xbox Dashboard, PC modding	Actual game files size (~500 MB – 6 GB)

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Format Deep Dives

1. ISO / XISO (Xbox & Xbox 360 Disc Images)

• XGD2: Standard Xbox 360 DVD-9 format with layerbreak 1913760 (~7.29 GB).
• XGD3: Extended Xbox 360 format utilizing disc overburn with layerbreak 2133520 (~8.13 GB).
• Scrubbing: XGDTool zeros out unused padding and junk sectors directly in memory buffers, avoiding redundant disk seek overhead.
• Automatic .dvd Generation: With the --dvd option or the corresponding checkbox in GUI/Android, XGDTool automatically generates a companion .dvd file pre-configured with the exact layerbreak, ready for burning with ImgBurn.

2. CSO & CCI (LZ4 Block-Compressed Images)

• Block Size: Uses 2 KB sector indexing with contiguous block chunking.
• Asynchronous Double-Buffering Ring Pipeline: While worker threads compress the current buffer, uncompressed data blocks are pre-fetched in background via std::async, completely eliminating disk read wait time.
• Lock-Free Multi-Threading: CSOWriter and CCIWriter utilize atomic work-stealing in 8-sector slices across all available CPU cores.
• Instant Decompression: LZ4 decompression runs at multiple gigabytes per second, making it ideal for handheld devices and emulation.

3. Games on Demand (GoD)

• Container Structure:
  • Root title folder (e.g. 45410887/00007000/).
  • Package header file (45410887...).
  • Data payload files split into chunks of ~162 MB (00007000/45410887...0000, ...0001, etc.).
• Master Hash Tables (MHT) & Sub-Hash Tables (SHT):
  • Each block contains cryptographic hash verification tables.
  • XGDTool reads all 204 blocks (816 KB) in a single read syscall before hashing, eliminating legacy single-sector seek delays.

4. ZAR (ZArchive / Zstandard)

• Specification: Open-source random-access compressed archive format designed for emulators.
• Multithreaded Parallel Engine: Uses cmake/zarchive_multithread.patch to compress 4 MB data block batches across all CPU cores with dedicated per-thread ZSTD_CCtx* contexts.
• Compression Presets:
  • Fast (Level 1): Maximum throughput (~150–200 MB/s compression).
  • Default (Level 2): Balanced standard for everyday use.
  • Balanced (Level 3): High compression efficiency.
  • Maximum (Level 6): Maximum space savings for cold storage.
  • Note: Emulator decompression throughput remains ultra-fast (~2 GB/s) across all compression levels.

5. Diagnostic Image Verification Engine

• Activated via --verify in CLI or the Verify Image button in GUI.
• Inspects disc layout, partition table, layerbreak, AVL filesystem integrity, and certificate headers.
• Extracts Title ID, Media ID, and Title Name without modifying or converting the disc.
• Streams hardware-accelerated CRC32, MD5, and SHA-1 checksums in a single pass.