NSZ is a compressed NSP and XCZ a compressed XCI. NSZ is a lossless compression format so you can convert back and forth between NSP and NSZ without losing any data. To decompress an NSZ file back to an NSP just use https://github.com/nicoboss/nsz with "python nsz.py -D YourCompressedGame.nsz"

 

No, You can not use this tool to unpack nsz. Only nsz->nsp

 

Today NSZ 2.1 got finally released!

NSZ 2.1.1:

• Fixed block compression for pip and Nuitka (nsz_win64_portable) by using sys.argv[0] instead of __main__.__file__ so threads no longer need to be prevented from initializing their own nut environment
• Made installation instructions easier to see and understand
• Scripts to automate testing and publishing

NSZ 2.1:

• 98 commits worth of changes since v2.0
• Added pip support
• Added Nuitka standalone windows build support
• Enhanced File Existing Check #20
  • Skip already compressed/decompressed files by default
  • --overwrite
  • --rm-old-version
  • Extracting TitleIDs and Versions from filename if possible (#17 and #19)
    • The titleID checking is now immensely faster than when extracting from Cnmt
  • --parseCnmt to get TitleID/version from Cnmt if not extractable from filename
    • Otherwise it falls back to simple filename checking which is much faster
• Batch error handling with tracebacks (#16)
  • Some debugging codes to find out erroneous files
  • Prevent batch process raising errors
  • Batch error handling with tracebacks
• The --thread option now works even for solid compression however the progress bar still has some visual glitches
• NSP/NSZ file hash verification now uses the hashes inside Cnmt instead of the nca filename (#22)
• Fixed decompression memory leak (#21)
  • The memory leak only occurs for dctx.stream_reader and was fixed by switching to the simple decompressing API which makes more sense for block decompression anyways
• Improved pageReadSize calculation speed by using math instead of a while loop
• Added option --remove-source that deletes the source file after compression or decompression (#24)
  • For this we finally properly closed file containers too
• Fix huge compression memory leak (#13)
• Fixed wrong working directory when starting nut.py from a different directory (#18)
• Improved exception handling during TitleID/Version extraction
  • Added support for prod.keys
• Reorganized file structure
• Fixed keys.txt path to always be the folder containing nsz.py
• Fixed default thread amount to be cpu_count()
• Implemented python version checking to prevent python from showing the users confusing compatibility related exceptions
  • Compatible and tested with Python 3.6 and later
• General system stability improvements to enhance the user's experience.

 

Block compressed NSZ/XCZ are compressed in chunks what makes them mountable. XCI files are known to be the mountable format so XCZ will use block compression by default while NSZ uses solid compression by default.

Block compressed NSZ/XCI mounting for PC will probably be released in the next few weeks. This will allow playing compressed games directly on emulator and use them with any tools not supporting NSZ/XCZ without decompression them first. When it will come to real hardware depends when and if Blawar manages to find somebody helping him to write a game mounting system model or if SX will implement XCZ support but that somebody will do it in the future seems quite likely.

Tinfoil currently already supports installing block compressed NSZ files but when doing so there's no benefit over solid NSZ. In the long-term block compressed NSZ seems to be better than solid compressed ones but if you never plan to mount your games there's no reason to use it as it comes with around 3% of compression ratio cost.

 

The NCAs are bit-identical. NSP is just a container similar to tar files and there are no clean NSPs as you can only dump/CDN download clean NCAs and repack them with unofficial tools. However nobody cares as it's just a container storing the actual files and the only real difference is the order in which the files are stored inside this container. Hash the NCA files instead and you are fine. Hashing NCAs other than for verification like NSZ does using the -V option is quite pointless as they are all already hashed. You find the official NCA hashes inside the CNMT file which the Nintendo Switch and NSZ uses to verify correctness. If you don't want to phrase CNMT: The NCA filename always corresponds to the first half of its SHA256 hash. If you really want NSPs to always have the same hash just repack them with the same tool you packed them in the first place but that's like the most pointless thing to do.

As you might already know NSZ removes completely useless delta fragments NCAs also often called NDV0 files. If you want to keep them, I can add a command storing them uncompressed for you. Or better just use nsZip and trim them to TCA as you can untrimmed them anyway what would save you multiple Terabytes. Please keep in mind that delta fragments have absolutely no use and are only made to save CDN band weight by only containing the modified data fragments between the current and a previous update. Keeping them is useless because you already have the updated NCAs with the applied patches.

In the end NSZ uses a completely lossless compression format and you will keep the exact same NCA files independent of how often you compress/decompress. Use -V to verify correctness while compressing all your games. I definitely would consider NSZ offering archival quality standards.

 

Yes use https://gbatemp.net/threads/ryjin-a-nsz-converter-mod.550174/
ryjin is NSZ just with a batch script packed as an exe containing a menu what to do. The next version of NSZ will most likely come with a GUI so I hope you are already looking forward to it. Alternatively https://github.com/julesontheroad/NSC_BUILDER whould probably be an option too. But keep in mind that command line really isn't that hard. If you download NSZ portable it's just "nsz -C inputFolder --level 22" to compress a full folder with the maximal compression level of level 22.

 

Code:

81% 30075486208 -> 24518742738  - 049dd08d818a01355283840a031a5922.nca

I tested the level 22 block compression on Witcher 3. It compressed the 28.0 GB nsp to a 22.8 GB nsz. That's not bad at all. It leaves more than enough space to install the high-quality audio mod, for example. I look forward to being able to save a lot of space on my SD card. Even Nintendo should be jealous; with compression several of the games they printed on 16 GB cartridges could have fit on 8 GB carts instead, saving them money.