Changes

Disc images (commonly known as ISOs , but ISO is actually a specific format) are faithful software recreations of game disksdiscs (when made correctly). However, at with disc sizes ranging from 700 MB (CD) / , 1.4 GB (GC Mini-DVD) / , 4.7 GB (single-layered DVD) / , and 25 GB (Blu-Ray), they can get pretty taxing to disk for storage, as especially when newer generations of consoles comegames are getting bigger in file sizes.

It wouldn't be so bad if not for the fact that the actually useful game data itself is often times only a fraction of that data the actual disc size - for instance, the ''Super Mario 25th Anniversary '' Wii disk disc itself is a 4.7GB , when really the actual game with data is only a single SNES rom and nothing else ROM (12 MB of useful data, to be precise)and nothing else. So naturallyNaturally, one would want to trim the this extra "fat " as much as possible. This , which is what this improved version of a previous guide page aims to help forto 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 , some methods alter the dump copy data foreverwhile others can be converted back and forth with generally no lost. Some conversion are only playable on only some specific emulators. And many light dumps are unplayable and may not work on real hardware (though a bunch are). All depending on the method console and the consolemethod used. So you might want It's important to consider take all of this into consideration beforeattempting as most of these are console-specific.

This page was based partially on this [https://www.reddit.com/r/emulation/comments/3g933n/guide_reduce_the_size_of_your_ps2_gc_wii_x360_ds/ guide]. '''Archive-quality dump means ''' dumps are ones that the resulting compressed dump, when reverted converted back to its original state, will be 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 dumps. 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.

Sega-CD, PC-Engine, PlayStation, Sega Saturn... what did do these all have in common was their reliance on the ? They all use a regular CD format. ! Game developers often stored often orchestrated/Redbook music and occasionally voice acting, other sounds using the Audio-CD format. Of course, the CD contained also game data. But but it was terribly inefficient when it comes to disk disc storageas it also had to store the actual game along with the sound files. Even 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.  That's why devs no longer used it, preferring custom audio formats included in the "game data" part of the disk. By the time the PS1 gen came, the Audio-CD part was just meaning games that used for messages like "Don't put this in a CD player, dumb user!" and little else (exceptions exist, lot of course!)sounds were limited in size.

* '''Full Dump:''' <br />BIN/ISO + CUE<br />BIN/ISO is the full disk data, including Since then developers no longer use Audio-CD sound data format and instead prefer custom audio formats that come included in the "game data<br />CUE is " part of the datasheet file* '''Light Dump:''' <br />ISO + MP3/WAV + CUE <br />ISO is disc. By the disk data with only time the game data<br />MP3/WAV is the sound data from PS1 generation came, the Audio-CDpart was just used for messages like "Don't put this in a CD player!" and little else (exceptions exist, but these formats take much less disk space<br />CUE is the datasheet fileof course!)

* '''Playable on Emulators?''' Yes (use virtual drive if needed). Some aren't compatible with MP3 so convert to WAV with MP32WAV , if that's the case, convert them to WAV with MP32WAV. You may need Sega Cue Maker.

Sometimes dumps that come this way may not work on some emulators. This is often due to either an incorrect CUE files sometimes using the wrong filenames or using MP3 files instead of WAV files.

Devs often have their games much, much bigger than they need to be. They put by putting in accessible garbage data in the diskdisc. Garbage data isn't useful game data and is just bloats used to bloat the disk disc size. It's either a sequence of 00/FF (you know what's inside a file if you open it with a hex editor) or randomized garbage , random data, unused/cut content left during development, and in rare cases, datathat is completely unrelated to the game itself. An example of this is ''Shrek SuperSlam'' on the PS2 which has a working copy of ''Tony Hawk's Underground 2'' for the PSP hidden in the root of the disc.

Its The purpose of doing this can be to fill in some spots in on the disk disc so that specific parts of the game 's data are in specific certain areas of the disk (like the borders) and hence disc. This is done to increase the drive's reading speed is so that it's quick enough in these certain spots for the game to work properly. It's in the your best of your interests interest not to mess with this data arrangement (referred to as LBA and TOC in the case of GC/Wii/PS2/PSP) or else as it might break the game might not even work in some cases (it might in others though).

BUT-- the most common bar none use Another reason for this is having garbage data can be to screw with pirates and people , who download ISOs off /upload these games online sharing websites, by making the ISO bigger and harder to downloadstore. Some go a little step further and make that scramble the garbage data, not instead of just being a sequence of 00/FF , to make the ISO much, much harder to compress using regular archive formats like zip/, 7zip/, rar.., etc. You might be overjoyed to learn this has become the industry standard nowadays.

* '''Playable on Emulators?''' Only MAME , DuckStation and DEmul. Some libretro cores for other emulators started adding are starting to add support.

MAME uses the CHD format for disc images in general and includes tools to convert from back and to itforth. It uses 7zip's LZMA compression on the game data and lossless FLAC compression for the audio data to optimize compression even further than with the using BIN+CUE+MP3/WAV data separation alone.

Placing '''Instructions'''Place chdman .exe and extractcd in the same directory as the dumps you want to compress (dumps must be in BIN+CUE format, ). Open Command Prompt and navigate to the directory where you placed chdman.exe and input one of the following command-line instructions can be used:

If you have one of the European PSX games that feature features LibCrypt copy protection, then you will have a .sbi file in addition to the .bin/cue file. The CHD creation process doesn't process the .sbi file. Thus, you 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 for the game ) in order to run.

* '''Gain:''' Not Immediate (ISO size doesn't change). ECM only zeroes out redundant error correction data (, but in some rare cases this data may be used for anti-piracy, hence corrupting the dump!). When coupled However it does achieves drastic size reductions when compressed to a compressed an archive format (7zip/gzip/zip) however it achieves drastic size reductions.* '''Tools Used:''' PakkISO or ECM Tools (from emuparadise download page). Drag-and-drop the iso on ISO onto the specific specified tool, then compress it with 7zip.

* '''Can be reverted?''' Yes, using the same tools (unECM). However, however there's is data loss (error correction data) which can damage a select few games. Check the hash with Redump to make sure nothing was altered.

* '''Playable on Emulators?''' Only on recent SVN builds of PCSX-R and ePSXe (they also support 7zip/gzip/zip archives so use them with ECM). Other emulators don't, so you convert manually the ECM dump to an ISO dump whenever you want to play it.

* '''Can be reverted?''' Yes. (For homemade EBOOTs) it can be done by using the same tool, to generate the BIN+CUE files; (for . For commercial releases from PSN) you will have to use [https://github.com/xdotnano/PSXtract PSXtract]. There's data loss, although but it's negligible in terms of functionality.

* '''Playable on Emulators?''' RetroArch, PCSX-R, and ePSXe. PlayStation 3's ps1_netemu (can also use it after packaging it into a PS1 Classic and installation of 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]).

Official format used by Sony for PS1 Classics on PSP and PS3===CHD===* '''Archive-quality dump?''' Yes* '''Gain:''' Immediate (better than PBP). Audio tracks may * '''Tools Used:''' chdman* '''Can be compressed in ATRAC3reverted?''' Yes, or as raw PCM using the same tool (unsupported chdman).* '''Playable on Hardware?''' No.* '''Playable on PS3Emulators?'s ps1_netemu'' libretro Beetle PSX, supported on PSP only by the earliest versions of POPS or the newest ones with the [http://wololo.net/talk/viewtopicAvocado, DuckStation and PCSX ReARMed.php?f=28&t=41330&start=60 cdda_enabler plugin])

Often, times you can just open the ISO in UltraISO and find the dummy files. Sometimes they're obviously are obvious looking files , like DUMMY.BIN, DATA0.BIN (or .DAT), DUMMY.DAT, etc. Or , or are folders named with names like "PADDING" and stuff like thatsuch. You can look into the files (with a hex editor) to see if they're obvious obviously padding data (usually the offsets will be full of 00/FF, though sometimes it's not as obvious). However, you must never mess with LBA and TOC when removing padding. <!--So you try to change the size of the padding file inside the ISO to 0 MB or alter it directly with a hex editor so that it's all zeroed out.--><!--Wording is too weird to figure out what it's say, will fix when more information is obtained-->

* '''Gain:''' Not Immediate (ISO dump size the same). Coupled , however when used with compression, however... the gain is really noticeable.* '''Tools Used:''' UltraISO, USBUtil, ExPERT/Xpert ([http://www.ps2-home.com/forum/viewtopic.php?t=3419 guides here])

* '''Playable on Hardware?''' Yes.(after GZIP-decompression) (some games may break)* '''Playable on Emulators?''' Yes.- PCSX2 (some games may break)

* '''Archive-quality dump?''' CHD v4: No (missing datadue to lossy compression, no gameplay issues). CHD v5: Possibly Archive-quality.

* '''Can be reverted?''' NoYes with CHD v5.

People used to resort to WiiScrubber (Wii) and GCM Utility (GC) to scrub/trim games to end up with dumps that while they had no immediate size change, their randomized garbage data (like "dummy", "padding" or "znull") was still there but zeroed out making archived dumps using zip/7zip/rar formats have stunning gains (from 1.4GB uncompressed to 26MB zipped for Animal Crossing for example!). Of course, the file still needed to be uncompressed to its full size everytime you wanted to play it. Trimming and scrubbing (in Wiiscrubber terms) aren't the same! While they both are terms for "zeroing garbage data" to make it more compression-friendly, trimming does not just that like scrubbing but takes the extra step of relocating the garbage data to the end of the file, hence altering its TOC and requiring the disc to be fakesigned, for a not-so-big compression gain. Hence why scrubbing is by far the most authentic and safe way to solve the garbage data problem. However compressed formats incorporating the "padding zeroing" part were made since then, and Dolphin supports them! These are the WBFS and GCZ formats. ===GCZ RVZ (Modern Dolphin native archive format) - GC/Wii===

The Dolphin team developed a new compression format based on WIA called RVZ. Unlike all the previous formats, RVZ is lossless and canpreserve the padding data on Wii discs as well as the necessary files needed by the Wii't play games directly from compressed archives (7zip/zip/gzip/rar...). Instead, it utilizes its own compression methods IOS.

* '''Archive-quality dump?''' Yes for GC games, Not directly for Wii games. (checksum won't be the same, no gameplay issues - may be unscrubbed with [https://gbatemp.net/threads/new-app-nkit-restore-shrink-and-preserve-disc-images-in-playable-formerly-swiit.533402/ NKitRestore])

* '''Tools Used:''' Dolphin 5.0-12188+ (right-click the game(s) in the games list and select "Compress ISO..." (or "Compressed selected ISOs..." if more than one is selected)); or [https://wit.wiimm.de/ wit (Wiimms ISO Tools)]* '''Can be reverted?''' Yes. You can right-click on the GCZ-compressed (in blue) ISOs in Dolphin and choose "Uncompress selected ISOs". Garbage data for Wii titles will be zeroed out and thus different from the official dump but will have no effect on gameplay in most cases - if desired can be unscrubbed [https://gbatemp.net/threads/new-app-nkit-restore-shrink-and-preserve-disc-images-in-playable-formerly-swiit.533402/ NKitRestore].* '''Playable on Hardware?''' No.

* '''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 (in case of scrubbing) [https://gbatemp.net/threads/new-app-nkit-restore-shrink-and-preserve-disc-images-in-playable-formerly-swiitNKit.533402/ NKitRestore]

Trimming games implies (also known as "trucha scrubbing", but and substantially different from the definition of "trimming" used in ROM-based systems) games will also remove defragment the garbage/dummy data outrightfiles moving them towards the start of the disc image, resulting in a smaller ISO file. The trimmed file can be used immediately at a smaller size without compression, but the game's internal structure will be wholly modified. '''Several games (the ones Games relying on direct sector access, (as opposed to consulting the filesystem) will break if you trim them.'''

* '''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 laboriously readded with wit or NKitRestore and a copy of the missing data).

* '''Archive-quality dump?''' (Gamecube) Not clear; (Wii) Not directly, see note about reversing.

* '''Can be reverted?''' Maybe. CISO files can always be converted back to ISO, but they will remain scrubbed (can be unscrubbed with NKitRestoresame caveats as WBFS).* '''Playable on Hardware?''' Yes (on Wii /Vwii only) - Nintendont for Gamecube games, uLoader for Wii games

* '''Gain:''' Immediate (ISO dump size lowers). Less More than WBFS.

* '''Can be reverted?''' Maybe. Just (same caveats as the previous formats, WIA files can always be converted back to ISO, but the conversion may be lossy (reversible with added workWBFS) depending on conversion settings.

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===* '''Archive-quality dump?''' Yes - by explicit design choice!* '''Gain:''' Immediate - (Wii) only for GCZ format.* '''Tools Used:''' NKit.* '''Can be reverted?''' Yes!* '''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, however it is directly playable in Dolphin. NKit ISO is the ideal space-saving option for Gamecube games.

* '''Archive-quality dump?''' No, with respect in regard to a disc image (update partition and padding dropped)discs; Most accurate format for Partially in regard to CDN dumps (digital titles)data.

* '''Can be reverted?''' No, if starting from a WiiU disc image; Yes (see below) if starting from extracted files

* '''Playable on Emulators?''' ?No

Consisting of a folder containing *.app, *.h3, title.cert, title.tik, and title.tmd files, this official Nintendo format intended for development use (is how tiles are stored on discs and some system titles are stored on the console and closely related is very similar to how digital titles are sold instored on the CDN (on the CDN the files are named differently, .app files are encrypted with the title key and common keys and the tmd has a certificate chain on the end that is same for every tmd) . This is equivalent to the files contained within a 3DS's CIA formatfile; however unlike a 3DS applicationtitle, converting a disc title to digital does not require modifying the title itself, thus leaving the title's signatures valid.

* '''Can be reverted?''' No, any padding/file order/signature information is lost.

* '''Archive-quality dump?''' No (data removed and edited), compared in regard to a gamecard dump. Potentially most accurate format for dumps; Partially in regard to CDN (digitally distributed) titlesdata.

Of courseSometimes, there are also the devs who don't merely use garbage data for padding but also bloat most bloated part of the game is the game data partitself, either intentional or because of poor design choices. For instance, many PSP JRPGs have a specific FMV movie duplicated a dozen times, and the Megaman Collection on GC GCN stores its sound data using an uncompressed format bringing the size of that portion alone to 1GB. In many of these cases, there's just not much you can do about it without destructively altering the game 's data.

So what do some people do? Note when I say , "deletedeleting" it often means replacing the file with a 1KB dummy file to prevent the ISO file structure from collapsing on itself, but sometimes such care isn't even put into ensuring it's still in a functional state. Some examples:

* delete all videos: this brings Super Smash Bros Brawl to 4.7GB(mainly due to Subspace Emissary).

* delete unused content you could get with emulator cheats like rooms and stuff.* delete "extra" languages other than Englishthe language you need.* If a game has multiple quests, they delete some then you could try deleting characters/quests they side-quest you don't like. Especially seen in compilations and stuff with demos includedas much.

Tools used for this are modding tools for rebuilding file trees, like UMDGen (PSP), Tinke (DS) and also regular ISO tools (PS1, Saturn)...

Since this results , in most of the case cases, in very noticeable detrimental effects in gameplay (if the game doesn't crash outright), this is nothing short of mutilating the game image. Some Sadly enough, some of these dumps make it to sharing sites sadly enough.

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 Verifyyour dumps]] your dumps to make sure you don't have these, and if you still want to compress those reduce size, prefer using other methods or using 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 (destructive modRemoves data)