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Since then developers no longer use Because these mixed CDs are difficult to properly archive just by using standard .ISO files, data-dumping software will usually do one of two things as a workaround:: '''Full Dump:''' BIN/ISO + CUE:* BIN/ISO is the full disc data, including Audio-CD sound data and game data:* CUE is the datasheet file: '''Light Dump:''' ISO + MP3/FLAC/WAV + CUE:* ISO is the disc data with only the game data:* MP3/FLAC/WAV is the sound data from the Audio-CD, but these formats take much less disk space:* CUE is the datasheet file Developers have long since stopped using the Audio-CD format , and instead prefer custom audio formats that come included in the "game data" part of the disc. By the time launch of the fifth generation CD-based consoles, i.e. the [[PlayStation emulators|PS1 generation came]] & the [[Sega Saturn emulators|Saturn]], it was more common than not to just use the Audio-CD part was just used for messages like "Don't put this in a CD player!" and little else (exceptions exist. That being said, there were still quite a few fifth-gen games that used Audio-CD data for their soundtracks, such as ''Vib-Ribbon'' and the ''Wipeout'' trilogy on the PS1, of course!)and ''Battle Garegga'' and ''Daytona USA'' on the Saturn.
* '''Full Dump:''' <br>BIN/ISO + CUE
<br>BIN/ISO is the full disc data, including Audio-CD sound data and game data
<br>CUE is the datasheet file
* '''Light Dump:''' <br>ISO + MP3/WAV + CUE
<br>ISO is the disc data with only the game data
<br>MP3/WAV is the sound data from the Audio-CD, but these formats take much less disk space
<br>CUE is the datasheet file
Dolphin can't play games directly from compressed archives ''This format has been deprecated in favor of [[#RVZ (7zip/zip/gzipModern Dolphin format) - GC/rar...). Instead, it utilizes its own compression methodWii|RVZ]].'''
Some examples:* '''Archive-quality dump?''' Yes* Super Mario Anniversary (Wii)'''Gain: 4''' Immediate. Considerable, depending on the game.7 GB (original) > 12 MB (GCZ) (!!)* Super Smash Bros Brawl (Wii)'''Tools Used: 7''' Dolphin 5.8 GB 0-12188+ (original) > 7.1 GB (GCZ) right-click the game(main cause is FMV's low compression)* Xenoblade PAL (Wii): 7in the game list and select "Convert File.8 GB (original) > 6.3 GB (GCZ)* Super Mario Galaxy 2 (Wii): 4.7 GB " (original) > 1or "Convert Selected Files.8 GB (GCZ)* Tales of Graces (Wii): 4.7 GB (original) > 4.2 GB (GCZ" if more than one is selected) (game data already fills the disk, and select RVZ)* Animal Crossing '''Can be reverted?''' Yes (GC): 1In Dolphin, right-click the game, select "Convert File..4 GB (original) > 26 MB (GCZ)* Zelda Four Swords Plus Japan (GC): 1.4 GB (original) > 480 MB (GCZ" and select ISO)* Zelda Twilight Princess (GC): 1.4 GB (original) > 1.4 GB (GCZ) (game data already fills the disk)'''Playable on Hardware?''' No* Megaman Collection (GC): 1.4 GB '''Playable on Emulators?''' Yes (original) > 1Dolphin 5.1 GB (GCZ) (sound data is stored as uncompressed stream to fill disk0-12188+)
→ZAR
Disc images (commonly known as ISOs, but ISO is actually a specific format) are faithful software recreations of game discs (when made correctly). However, with disc sizes ranging from 700 MB (CD), 900 MB (PSP single-layered UMD), 1 GB (DC GD), 1.4 46 GB (GC GCN Mini-DVD), 1.8 GB (PSP dual-layered UMD), 4.7 GB (single-layered DVD), 8.5 GB (dual-layered DVD), 25 GB (single-layered Blu-Ray), and 25 50 GB (dual-layered Blu-Ray), they can get pretty taxing for storage, especially when newer generations of consoles games are getting bigger in file sizes.
It wouldn't be so bad if not for the fact that the game data itself is often times only a fraction of the actual disc size - for instance, the ''Super Mario 25th Anniversary'' Wii disc itself is a 4.7GB, when really the actual game data is only a single SNES ROM (12 MB of useful data, to be precise) and nothing else. Naturally, one would want to trim this extra "fat" as much as possible, which is what this page aims to help to achieve. Most of the information here is based partially on this [https://www.reddit.com/r/emulation/comments/3g933n/guide_reduce_the_size_of_your_ps2_gc_wii_x360_ds/ guide].
'''How does one lighten ISO / ROM dumps?'''
There are many ways, some methods alter the data forever while others can be converted back and forth with generally no lostloss. Some conversion conversions are only playable on specific emulators and may not work on real hardware depending on the console and the method used. It's important to take all this into consideration before attempting as most of these are console-specific.
'''Archive-quality''' dumps are ones that when converted back to its original state, will have the same checksum as the official uncompressed release. Compressions that can't be reversed, or those that can be but will have missing or altered content whether it interferes with functionality (rebuilt table of content) or not, are not archive-quality. For example, the WBFS format, used for shrinking Wii discs, is not archive-quality since it may be missing padding content and upgrade partitions (which have their uses in 3DS/Wii modding) compared to an intact, uncompressed dump.
==Applicable to All Platforms==
===Audio-CD===
PCs, Sega-CD, PC-Engine, PlayStation, Sega Saturn... what do these systems all have in common? They all use a regular CD format! Game developers often stored music and other sounds using the Audio-CD format, but it was terribly inefficient when it comes to disc storage as it also had to store the actual game along with the sound files(commonly known as a "mixed CD"), and these sound files are never compressed because the Audio-CD standard simply doesn't allow for sound compression. To put it in perspective, a 700 MB CD containing nothing but Audio-CD data can hold at most around 80 minutes worth of sound data, meaning games that used a lot of sounds where were limited in size.
* '''Archive-quality dump?''' No (unless audio is converted to and from uncompressed formats, which is unlikely)
* '''Gain:''' Several hundreds of MBs to just a few dozens, depending on how much this specific game relies on the Audio-CD sound format
* '''Tools Used:''' Load the BIN+CUE using a virtual drive, then use a CD dumping tool
* '''Can be reverted?''' Yes, just burn the ISO+MP3/FLAC/WAV+CUE again using a CD burner tool (ImgBurner) either to a physical disk or as an ISO+BIN file. Lossy audio formats will result in data loss.
* '''Playable on Hardware?''' No, but can be reverted to be
* '''Playable on Emulators?''' Yes Anything that supports loading from .cue files, or direct from the optical drive (if you use a virtual drive if neededdisc loader like CDEmu). Some aren't compatible with MP3, if that's the case, convert them to WAV with MP32WAV. You may need Sega Cue Maker.
Examples:
===CHD Compression===
* '''Archive-quality dump?''' YesNo (because of bugs and missing unimplemented directives<ref>http://problemkaputt.de/psxspx-cdrom-disk-images-chd-mame.htm#CHD_Notes</ref><ref>http://github.com/mamedev/mame/issues/10308</ref>)
* '''Gain:''' Immediate
* '''Tools Used:''' chdman (included with MAME)
* '''Can be reverted?''' Yes, using extractcd (included with MAME)
* '''Playable on Hardware?''' No.
* '''Playable on Emulators?''' MAME, DuckStation , PCSX2 (since March of 2021), DEmul and DEmulNO$PSX. Some libretro cores for other emulators are starting to add support.
* '''Can process multi track bin files?''' Yes.
MAME uses the CHD format for disc images in general and includes tools to convert back and forth. It Before MAME v145, CHD was in version 4 and it bumped to version 5 from MAME v146 and further. The CHDv5 uses 7zip's LZMA compression on the game data and lossless FLAC compression for the audio data to optimize compression even further than using BIN+CUE+MP3/WAV data separation alone. CHDv5 is lossy until all the bugs are resolved.
'''Instructions'''
Place the chdman.exe executable and extractcd in the same directory as the dumps you want to compress (dumps must be in BIN+CUE formator GDI). Open Command Prompt or a terminal emulator and navigate to the directory where you placed the chdman.exe executable and input one of the following:* BIN/CUE -GDI to CHD: <code> for /R %i in (*.cue, *.gdi) do chdman createcd -i "%i" -o "%~ni.chd"</code> (Windows) for i in *.(cue|gdi); do chdman createcd -i "$i" -o "${i%.*}.chd"; done (Linux)* CHD to BIN/CUE: <code> for /R %i in (*.chd) do chdman extractcd -i "%i" -o "%~ni.cue"</code> (Windows) for i in *.chd; do chdman extractcd -i "$i" -o "${i%.*}.cue"; done (Linux)
Alternatively, if you only need to do one file you can use this: <code>chdman createcd -i "<FILENAME>.cue" -o "<FILENAME>.chd"</code>
If you have one of the European PSX games that features LibCrypt copy protection, then you will have a .sbi file in addition to the .bin/cue file. You will still need to have the .sbi file in the same directory as the game file (in this case, the newly created CHD file) in order to run.
Note that multi-track bin files will be combined and chdman will not split the files back when extracting.
==PlayStation 1==
* '''Archive-quality dump?''' No
* '''Gain:''' Immediate (ISO size decreases a lot).
* '''Tools Used:''' [https://www.reddit.com/r/PSP/wiki/psx2psp PSX2PSP], Popstation MD GUI, [https://www.psx-placegithub.com/threadssahlberg/w-ipop-p-utilities-cdda-enabler-for-psx-eboots-on-ps3.23539/ CDDAfe POP-ENABLERfe] (optimized for PS3friendly) , ...
* '''Can be reverted?''' Yes. For homemade EBOOTs it can be done by using the same tool to generate the BIN+CUE files. For commercial releases from PSN you will have to use [https://github.com/xdotnano/PSXtract PSXtract]. There's data loss, but it's negligible in terms of functionality.
* '''Playable on Hardware?''' On PSP, not on PS1.
* '''Playable on Emulators?''' RetroArch, PCSX-R, DuckStation and ePSXe. PlayStation 3's ps1_netemu can also use it after packaging it into a PS1 Classic and installing said package.
PBP is the official format used by Sony for the PS1 Classics on PSP and PS3. Audio tracks may be compressed in ATRAC3 or as raw PCM (unsupported on PS3's ps1_netemu, supported on PSP only by the earliest versions of POPS or the newest ones with the [http://wololo.net/talk/viewtopic.php?f=28&t=41330&start=60 cdda_enabler plugin])
===CHD===
* '''Archive-quality dump?''' YesNo (because of bugs and unimplemented directives for TOC and CUE)
* '''Gain:''' Immediate (better than PBP).
* '''Tools Used:''' chdman
* '''Can be reverted?''' Yes, using the same tool (chdman).
* '''Playable on Hardware?''' No.
* '''Playable on Emulators?''' libretro Beetle PSX, Avocado, DuckStation , PCSX2 (since March of 2021 and also because PCSX2 now has PSOne emulation functionality as well, so two-in-one), PCSX ReARMedand NO$PSX.
==PlayStation 2==
Use 7zip ("Add to archive..." then choose to gzip) or Pigz (multi-threaded, much faster compression) to generate gzip archives containing the ISO file in question. PCSX2 will build an index of each gzip compressed game it loads (as a file in the same directory as the gzip archive), so after the first time where you'll have to wait for the decompression, in all subsequent times there is no speed difference between playing an uncompressed and compressed game. Of course, you can extract the ISO back from the GZIP archive.
A simple method to mass convert a lot of PS2 ISO games to GZIP is this script when run in PowerShell. However, it'll take many hours or days depending on the size of the collection.
<blockquote>dir *.iso | ForEach-Object { & "C:\Program Files\7-Zip\7z.exe" a -tgzip -mx9 -sdel ($_.Name+".gz") $_.Name }</blockquote>
===CSO (aka CISO)===
* '''Archive-quality dump?''' No (missing data)Yes
* '''Gain:''' Immediate (ISO dump size the same). Coupled with manual scrubbing, it can be bigger. Not as much of a gain as GZIP though.
* '''Tools Used:''' maxcso
* '''Playable on Hardware?''' NO
* '''Playable on Emulators?''' Yes - PCSX2.
===ZSO (aka ZISO)===
* '''Archive-quality dump?''' Yes
* '''Gain:''' Immediate (ISO dump size the same). Coupled with manual scrubbing, it can be bigger. Not as much of a gain as GZIP though.
* '''Tools Used:''' [https://github.com/unknownbrackets/maxcso#features maxcso], [https://github.com/ps2homebrew/Open-PS2-Loader/blob/master/pc/ziso.py ziso.py (requires python3 and pip install lz4)], [https://www.psx-place.com/resources/psxiso-compression-tool.1258/ PSXiSO (contains ziso CLI tool)]
* '''Can be reverted?''' Yes, using the same tool. No data loss.
* '''Playable on Hardware?''' Yes - Open PS2 Loader.
* '''Playable on Emulators?''' Yes - PCSX2 (since v1.7.5293)<ref>[https://github.com/PCSX2/pcsx2/releases/tag/v1.7.5293 v1.7.5293]</ref>
===CHD===
* '''Archive-quality dump?''' Yes
* '''Gain:''' Immediate (better than GZIP).
* '''Tools Used:''' chdman
* '''Can be reverted?''' Yes, using the same tool (chdman).
* '''Playable on Hardware?''' No.
* '''Playable on Emulators?''' Yes - PCSX2 (since v1.7.0-dev-1156)<ref>Added in 1150 but wasn't built. 1156 is the first release with CHD support. [https://web.archive.org/web/20210416020418/https://buildbot.orphis.net/pcsx2/index.php?m=fulllist Automated Pcsx2 builds]</ref>
==PlayStation 3==
For a long time (before the availability of Cobra and Mamba) the only playable format for PS3 backups (relying on little more than "peek and poke" CFW-provided syscalls to mount the game's folder over the currently inserted disc) but also the least accurate one, with significant compatibility issues (varying on whether the backup is stored on an internal or external drive, whether an original game disc is currently inserted, various optional hacks such as "BDMirror" moving the files to the root of the external drive on demand, ...)
===ISO support for RPCS3===
Currently [[Save_disk_space_for_ISOs#External_links|there is no direct ISO or any compressed file support for RPCS3]] (your only option is mount ISO image to boot the game with RPCS3).
*You can either use [https://github.com/RPCS3/rpcs3/issues/4021#issuecomment-1650682400 this tool], or [https://github.com/ptmorris1/RPCS3-ISOLauncher-Launchbox this one] for playing directly your ISO dumps with RPCS3.
*or use [https://www.mediafire.com/file/v5yslivyurr5luy/Make_sure_edit_path_locations_first.bat/file this simple batch script] ('''edit path locations first of course''') which mounts your ISO using powershell commands and launching it using RPCS3 CLI commands and ejecting it when you done with RPCS3
==PlayStation Portable==
Official format for digitally distributed PSP/minis (partially related to the one used for PS1 games), containing a compressed disc image and optionally a custom boot logo.
===CHD===
* '''Archive-quality dump?''' Yes
* '''Gain:''' Immediate (Less than PBP).
* '''Tools Used:''' chdman
* '''Can be reverted?''' Yes, using the same tool (chdman).
* '''Playable on Hardware?''' No.
* '''Playable on Emulators?''' Yes - PPSSPP.
==PlayStation Vita==
* '''Can be reverted?''' No.
* '''Playable on Hardware?''' Yes - with the NoNpDRM plugin.
* '''Playable on Emulators?''' ?Yes - Vita3K
NoNpDRM is a Vita plugin that generates decrypted licenses (valid for any console) when running an original Vita title, as well as allowing the system to accept those licenses, allowing for playing the encrypted files directly copied from a game card or memory card (by extension the name is therefore also used for such files, or the combination of the game's files and a decrypted license).
* '''Can be reverted?''' Yes with CHD v5.
* '''Playable on Hardware?''' No
* '''Playable on Emulators?''' Yes - DEmul, Reicast , Flycast, and Redream
==GameCube / Wii==
However compressed formats incorporating the "padding zeroing" part were made since then, and Dolphin supports them! These are the WBFS and GCZ formats.
Dolphin can't play games directly from compressed archives (7zip/zip/gzip/rar...). Instead, it utilizes its own compression method.
===GCZ (Dolphin native archive format) - GC/Wii===
* '''Archive-quality dump?''' Yes (Not directly (can be restored with NKitif scrubbed; see reverting notes).* '''Gain:''' Immediate (ISO dump size lowers). Considerable, depending Depends on the game. It is very minimal if junk data is not removed (scrubbed).* '''Tools Used:''' Dolphin (right-click the game(s) in the games list and select "Compress ISOConvert File..." (or "Compressed selected ISOsConvert Selected Files..." if more than one is selected), and select GCZ), [https://wiki.gbatemp.net/wiki/NKit NKit], or [https://wit.wiimm.de/ wit (Wiimms ISO Tools)], Nkit (for indirect recovery)* '''Can be reverted?''' Yes. You can right-click on the GCZ-compressed (in blue) ISOs in Dolphin and choose "Uncompress selected ISOs". Garbage data Directly for Wii titles will be zeroed out and thus different from the official dump but will have no effect on gameplay in most cases non- if desired can be unscrubbed [https://gbatemp.net/threads/new-app-nkit-restore-shrink-and-preserve-disc-images-in-playable-formerly-swiit.533402/ NKitRestore]scrubbed files.For scrubbed files, first convert to ISO, then use Nkit tool's "Recover to ISO" option)
* '''Playable on Hardware?''' No
* '''Playable on Emulators?''' Only Yes (Dolphin) ===RVZ (Modern Dolphin format) - GC/Wii=== The Dolphin team developed a new compression format based on WIA called RVZ. Usage is very similar to GCZ in Dolphin itself, but it only works on newer Dolphin versions. It can efficiently compress both the actual data and junk data, without altering the file/directory structure.
===Scrubbing and Trimming - GC/Wii===
* '''Tools Used:''' GC-Tool ("wipe garbage data..." - Scrubbing for GameCube), GameCube ISO Trimmer (scrubbing and trimming for GameCube), WiiScrubber (scrubbing/trimming for Wii, although compressing with Dolphin will scrub it anyways).
* '''Can be reverted?''' Yes, with WiiScrubber's undo file or NKit.
* '''Playable on Hardware?''' Yes for scrubbingscrubbed; some games won't work trimmed.* '''Playable on Emulators?''' Yes for scrubbingscrubbed; some games won't work trimmed.
Scrubbing games zeros out garbage/dummy data in the ISO file. The resulting file will be the same size, but it will be able to compress better than unmodified ISOs. The difference can be huge depending on the game. Animal Crossing, for instance, will compress to just a 26 MB .gcz file after being scrubbed!
===WBFS - Wii only===
* '''Archive-quality dump?''' Not directly, ; see note about reversingreverting notes.
* '''Gain:''' Immediate (ISO dump size lowers). Considerable, depending on the game.
* '''Tools Used:''' [http://www.wiibackupmanager.co.uk/downloads.html Wii Backup Manager] (after adding your game, go to "Transfer" and select "WBFS") or wit (Wiimms ISO Tools).
* '''Can be reverted?''' Maybe. WBFS files can always be converted back to ISO, but they will remain scrubbed (can be unscrubbed with NKitRestore) and, depending on settings at the time of conversion to WBFS, may be missing update/extras partitions (can be readded with wit or NKitRestore and a copy of the missing data).
* '''Playable on Hardware?''' Yes - Preferred format by most SD/USB loaders
* '''Playable on Emulators?''' Yes - (Dolphin)
A scrubbed and sparse (gap-dropping) format directly derived from the one used in the obsolete WBFS file system.
* '''Can be reverted?''' Maybe (same caveats as WBFS).
* '''Playable on Hardware?''' Yes (on Wii/Vwii only) - Nintendont for Gamecube games, uLoader for Wii games
* '''Playable on Emulators?''' Yes - (Dolphin)
A scrubbed and sparse (gap-dropping) format. Unrelated to the PSP's CSO format.
===FST (extracted File System) - GC/Wii===
* '''Archive-quality dump?''' No(Yes, if not scrubbed)
* '''Gain:''' Very low with GC ISOs, much better with Wii ones. Can also be combined with classic archives compression (ZIP/RAR/7z etc.) to match WIA and NKit compression ratios.
* '''Tools Used:''' [https://wit.wiimm.de/info/composing.html wit]
* '''Can be reverted?''' Partially via the align-files.txt created by wit when extracting.
* '''Playable on Hardware?''' (GC games on Wii/Vwii): Yes - ([https://github.com/FIX94/Nintendont/ Nintendont]. () / Other combinations): No* '''Playable on Emulators?''' Yes - (Dolphin (both GC and Wii)
This has the advantage of easy experimenting with [[#Destructive Modification]]. Includes all disadvantages of trimming.
===WIA (Wii ISO Archive) - GC/Wii only?===* '''Archive-quality dump?''' Not directly unless --raw option is given; see reverting notes (Yes, effectively preventing any space savings.if not scrubbed)* '''Gain:''' Immediate (ISO dump size lowers). More ; more than WBFS.(No gain if not scrubbed and compression not used)* '''Tools Used:''' wit, Dolphin 5.0-12188+, Nkit (for indirect recovery)* '''Can be reverted?''' Maybe Yes (same caveats as WBFSDirectly, if not scrubbed. Not directly, if scrubbed, by converting it to ISO first, and then using Nkit tool's "Recover to ISO" option).
* '''Playable on Hardware?''' No
* '''Playable on Emulators?''' NoYes (Dolphin 5.0-12188+)
A scrubbed and compressed format designed for maximum space savings without cutting corners on corruption detection, but it's not directly playable or editable. Never really caught on and may be considered de facto deprecated by NKit.
===NKit formats - GC/Wii===
'''This format has been deprecated in favor of [[#RVZ (Modern Dolphin format) - GC/Wii|RVZ]]. ([https://github.com/Nanook/NKit/wiki Developer's Wiki])'''* '''Archive-quality dump?''' Yes - by explicit design choice!(Not for Wii games, if the Wii update partition is removed and the recovery file not preserved)* '''Gain:''' Immediate - (Wii) only for GCZ format.* '''Tools Used:''' NKit.* '''Can be reverted?''' Yes!(unless the Wii update partition was removed and the recovery file not preserved)* '''Playable on Hardware?''' (GC) : Yes - (ISO-based variant only () / Wii) : No* '''Playable on Emulators?''' Yes - (Dolphin)
Apart from its previously mentioned unscrubbing/untrimming features mentioned in the above formats' descriptions, NKit is able to convert any ISO (clean dump or otherwise) to and from an [https://wiki.gbatemp.net/wiki/NKit/NKitFormat intermediate format applying various reversible changes] that optimize the image for lossless compression, including full decryption and optionally splitting the often non-unique update partitions to separate files.
NKit-.GCZ (as well as plain GCZ) is less space efficient than NKit-.ISO compressed with a powerful general purpose archiver(7zip), however it is directly playable in Dolphin. It has problems with emulation, such as slower emulated load times, breaking netplay if load times aren't the same, and crashing a few games.
Compressing NKit .ISO is with a strong compression format gives the ideal space-saving option for Gamecube gamessmallest size while being reversible.
==Wii U==
* '''Can be reverted?''' Yes. The wud tool includes a decompression utility, which recreates the original file.
* '''Playable on Hardware?''' No (can be converted to an installable format using [https://github.com/FIX94/wud2app wud2app])
* '''Playable on Emulators?''' Yes - Future releases of Cemu (and potentially other [[Wii U emulators]])
By Exzap, Cemu's author ([http://gbatemp.net/threads/wii-u-image-wud-compression-tool.397901/ release thread]). The tool detects duplicate sectors and only stores them once: all the empty ranges end up removed, storing only ranges which contain file or filesystem data. Of course, the original ISO can be reconstituted.
Ideal format for game modding, less so for playing on console due to Loadiine's intrinsic modus operandi (appearing to the OS as the host title, with potentially different permissions) leading to poor compatibility.
===WUA (Wii U Archive)===
* '''Archive-quality dump?''' No (based on extracted format, see above)
* '''Gain:''' Immediate (Total size decreases, adds compression to the extracted format).
* '''Tools Used:''' Cemu (introduced in v1.27)
* '''Can be reverted?''' No (based on extracted format, see above)
* '''Playable on Hardware?''' No
* '''Playable on Emulators?''' Yes - Cemu (since v1.27)
Cemu (since 1.27) can convert installed titles to WUA, combining the title itself, update (if available) and DLC (if available) into one file. The conversion tool is available via the Cemu title manager.
Based on a small testset of 44 titles with updates and dlc, WUA reduced the overall file size by roughly 16%. It also reduced the number of files per title from 3,500 on average to 1.
==Switch==
===NSZ===
* '''Archive-quality dump?''' Yes
* '''Gain:''' Immediate (Total size decreases)
* '''Tools Used:''' [https://github.com/nicoboss/nsz nsz]
* '''Can be reverted?''' Only NCAs are fully reversible; compressed XCI and NSP files will be different when decompressed
* '''Playable on Hardware?''' No
* '''Playable on Emulators?''' No
It is possible to merge the game base, update and DLCs on a single NSP with the tool [https://github.com/julesontheroad/NSC_BUILDER NSC_Builder] and compress it to NSZ
==Game Boy Advance / Nintendo DS / Nintendo 3DS==
* '''Playable on Hardware?''' Yes. If the rebuilding process didn't damage anything vital.
* '''Playable on Emulators?''' Yes - Xenia.
===ZAR===
[https://github.com/xenia-canary/xenia-canary/pull/165 This Pull Request] adds support to [[xenia]] emulator for loading ZAR (ZArchive files) of a decrypted and extracted dump of XBOX 360 game.
*The process is basically to dump your disc, extract files using your favorite tool, and create a ZAR file from it using ZArchive tool or [https://github.com/xenia-canary/xenia-canary/pull/299 xenia-canary->create Zar package option].
*For digital titles (Xbox 360 Demos, Video DLC and XBLA games etc) you need to extract the contents from its containers using "[https://digiex.net/threads/wxpirs-extract-content-from-xbox-360-demos-video-dlc-and-arcade-game-containers.9464/ wxPirs]" and then create a ZAR file from it using the "[https://github.com/Exzap/ZArchive/releases ZArchive]" tool or xenia-canary->create Zar package option[https://github.com/xenia-canary/xenia-canary/pull/165#issuecomment-1641099753].
=Other Tricks=
===NTFS Compression===
You can enable filesystem-level compression (like "NTFS Compression" in Windows) for the directory containing your ISOs/ROMs. This has a very noticeable space gain and doesn't affect the emulator's functionality. It's surprisingly more effective than many people would like to give this credit.
* '''Archive-quality dump?''' Yes
===Decompression on Demand===
You can keep your ROMs/ISOs compressed in a 7zip archive and use RocketLauncher or any other [[Frontends]] to decompress 7zip archives and pass the contents onto the emulator.
* '''Archive-quality dump?''' Yes
===FileSystem Deduplication, alternative file systems===
If you use macOS, you can look up for fuse filesystems which support compression/deduplication. <br />
If you use windows, you can fire a VM/store your games on ,a pc with a transparent network file server running linux/bsd.(might be viable on low latency networks, and a fast file server) <br />
On linux and bsds one can use, filesystems with de-duplication(and possibly transparent file compression) like:
* '''Squashfs'''
* '''Note:''' you can mount the filesystem and use an overlay file system to add a new file, and then create a new squashfs against an overlay folder.
** '''ReadWriteable?''' No read-only.
** '''Deduplication?''' Yes, block level.
** '''Active Deduplication?''' No, Deduplication is triggered by the user, during filesystem creation.
** '''Available compressors:''' zstd, xz(lzma2), lzma, gzip, lz4, lzo.
** '''Compression level control:''' Depends on the compression algorithm, xz dictionary size depends on filesystem block size.
** '''Transparent?''' On Linux and BSD via kernel. Squashfuse avaialble for macOS.
* '''Btrfs'''
** '''ReadWriteable?''' Yes.
** '''Deduplication?''' Yes, file and block level.
** '''Active Deduplication?''' No, Deduplication is triggered by the user.
** '''Available compressors:''' zstd, zlib, lzo.
** '''Transparent?''' On Linux via kernel.
* '''Zfs'''
** '''ReadWriteable?''' Yes.
** '''Deduplication?''' Yes, file and block level.
** '''Active Deduplication?''' Yes, deduplication happens during writes.(high memory requirements)
** '''Available compressors:''' zstd, zlib, lzo.
** '''Transparent?''' On Linux, BSD, via kernel. Openzfs on mac os(?).
* '''Xfs'''
* '''Note:''' Without de-duplication it is already quite efficient at storing files.
** '''ReadWriteable?''' Yes.
** '''Deduplication?''' Yes, file level via duperemove.
** '''Active Deduplication?''' No, deduplication is triggered by the user.
** '''Available compressors:''' None.
** '''Transparent?''' On Linux and BSD via kernel.
* '''Archive-quality dump?''' Yes
Since this results, in most cases, in very noticeable detrimental effects in gameplay (if the game doesn't crash outright), this is nothing short of mutilating the game image. Sadly enough, some of these dumps make it to sharing sites.
Avoid resorting to destructive modifications since it can lead to random crashes and unexpected behavior, especially in games with lots of shared assets. [[http://emulation.gametechwiki.com/index.php/File_Hashes File hashes|Verify your dumps]] to make sure you don't have these, and if you still want to reduce size, prefer using other methods or uses decompression on demand. One reason to use a destructively modified dump is for burning your own Dreamcast games as GD-ROMs were over a gigabyte in size and CD-Rs top out at 850MB.
* '''Archive-quality dump?''' No (Removes data)
=See also=
*[[List of filetypes]]
=External links=
*[https://github.com/citra-emu/citra/issues/6013 CHD or ZArchive feature requests for citra]
*[https://github.com/RPCS3/rpcs3/issues/4021 CHD or ZArchive feature requests for RPCS3]
*[http://web.archive.org/web/20231127115239/https://github.com/yuzu-emu/yuzu/issues/10025#issuecomment-1493873239 CHD or ZArchive feature requests for yuzu and Ryujinx]
*[https://github.com/xemu-project/xemu/issues/129 CHD or ZArchive feature requests for xemu]
*[https://github.com/86Box/86Box/issues?q=is%3Aissue+is%3Aopen+format+label%3Afeature+ Various image format feature requests for 86Box]
*[https://github.com/joncampbell123/dosbox-x/issues/1822 CHD feature request for DOSBox-X]
*[https://github.com/schellingb/dosbox-pure/issues/40 CHD feature request for DOSBox Pure]
*[https://yuzu-emu.org/entry/yuzu-progress-report-aug-2023/#project-terra yuzu now supports sparse and compressed NCA games]. This means a long list of titles whose eShop releases couldn’t previously boot are now either running or perfectly playable, and their RomFS can be fully dumped.
=References=
[[Category:FAQs]]
