Save disk space for ISOs: Difference between revisions

Line 7:

There are many ways, some methods alter the data forever while others can be converted back and forth with generally no loss. Some 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.

'''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|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.

=Optical disc images=

Line 34:

;Light Dump

* '''Archive-quality dump?''' No. Even if the audio is kept pristine using a lossless format like FLAC, a Light Dump strips away precise track gaps, write offsets, and subchannel data (like CD-Text or copy protection). It is a preservation compromise for storage saving, not a true archival dump.

* '''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|Archive-quality dump]]?''' No. Even if the audio is kept pristine using a lossless format like FLAC, a Light Dump strips away precise track gaps, write offsets, and subchannel data (like CD-Text or copy protection). It is a preservation compromise for storage saving, not a true archival dump.

* '''Gain:''' Saves several hundred megabytes, depending on how much of the disc was dedicated to red-book audio.

* '''Tools Used:''' Virtual drive mounters (Daemon Tools, CDEmu) combined with CD ripping software (EAC, TurboRip).

Line 59:

;CHD Compression

* '''Archive-quality dump?''' Probably no (because of bugs and missing unimplemented directives<ref>http://problemkaputt.de/psxspx-cdrom-disk-images-chd-mame.htm#CHD_Notes</ref> MAME uses the CHD format for disc images in general and includes tools to convert back and forth. 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. Note that multi-track bin files will be combined and chdman will not split the files back when extracting.<ref>http://github.com/mamedev/mame/issues/10308</ref><ref>[https://github.com/mamedev/mame/issues?q=is%3Aissue%20state%3Aopen%20CD%20chd mame issues for chdman tool]</ref><ref>[https://old.reddit.com/r/emulation/comments/1kdpx87/ymir_a_new_sega_saturn_emulator_for_windowslinux/mqjy0rk/ amroamroamro's comment about chdman for CDs]</ref>)

* '''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|Archive-quality dump]]?''' Probably no (because of bugs and missing unimplemented directives<ref>http://problemkaputt.de/psxspx-cdrom-disk-images-chd-mame.htm#CHD_Notes</ref> MAME uses the CHD format for disc images in general and includes tools to convert back and forth. 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. Note that multi-track bin files will be combined and chdman will not split the files back when extracting.<ref>http://github.com/mamedev/mame/issues/10308</ref><ref>[https://github.com/mamedev/mame/issues?q=is%3Aissue%20state%3Aopen%20CD%20chd mame issues for chdman tool]</ref><ref>[https://old.reddit.com/r/emulation/comments/1kdpx87/ymir_a_new_sega_saturn_emulator_for_windowslinux/mqjy0rk/ amroamroamro's comment about chdman for CDs]</ref>)

* '''Gain:''' Immediate

* '''Tools Used:''' chdman (included with MAME) ([https://github.com/DesertDoggy/CHDlite/ CHDlite)](Basically a CHDman wrapper with added functions), [https://play.google.com/store/apps/details?id=it.ottaviomiele.chd CHDroid] (for Android), [https://romtools.io/ ROM Tools] (web-based), [https://chd.emulationonline.com/ CHD Creator] (web-based, for converting bin/cue to chd)

@@ Line 7: / Line 7: @@
 There are many ways, some methods alter the data forever while others can be converted back and forth with generally no loss. Some 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.
+'''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|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.
 =Optical disc images=
@@ Line 34: / Line 34: @@
 ;Light Dump
-* '''Archive-quality dump?''' No. Even if the audio is kept pristine using a lossless format like FLAC, a Light Dump strips away precise track gaps, write offsets, and subchannel data (like CD-Text or copy protection). It is a preservation compromise for storage saving, not a true archival dump.
+* '''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|Archive-quality dump]]?''' No. Even if the audio is kept pristine using a lossless format like FLAC, a Light Dump strips away precise track gaps, write offsets, and subchannel data (like CD-Text or copy protection). It is a preservation compromise for storage saving, not a true archival dump.
 * '''Gain:''' Saves several hundred megabytes, depending on how much of the disc was dedicated to red-book audio.
 * '''Tools Used:''' Virtual drive mounters (Daemon Tools, CDEmu) combined with CD ripping software (EAC, TurboRip).
@@ Line 59: / Line 59: @@
 ;CHD Compression
-* '''Archive-quality dump?''' Probably no (because of bugs and missing unimplemented directives<ref>http://problemkaputt.de/psxspx-cdrom-disk-images-chd-mame.htm#CHD_Notes</ref> MAME uses the CHD format for disc images in general and includes tools to convert back and forth. 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. Note that multi-track bin files will be combined and chdman will not split the files back when extracting.<ref>http://github.com/mamedev/mame/issues/10308</ref><ref>[https://github.com/mamedev/mame/issues?q=is%3Aissue%20state%3Aopen%20CD%20chd mame issues for chdman tool]</ref><ref>[https://old.reddit.com/r/emulation/comments/1kdpx87/ymir_a_new_sega_saturn_emulator_for_windowslinux/mqjy0rk/ amroamroamro's comment about chdman for CDs]</ref>)
+* '''[[Ripping_games#Preservation_Priority_(Recommended_Workflow)|Archive-quality dump]]?''' Probably no (because of bugs and missing unimplemented directives<ref>http://problemkaputt.de/psxspx-cdrom-disk-images-chd-mame.htm#CHD_Notes</ref> MAME uses the CHD format for disc images in general and includes tools to convert back and forth. 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. Note that multi-track bin files will be combined and chdman will not split the files back when extracting.<ref>http://github.com/mamedev/mame/issues/10308</ref><ref>[https://github.com/mamedev/mame/issues?q=is%3Aissue%20state%3Aopen%20CD%20chd mame issues for chdman tool]</ref><ref>[https://old.reddit.com/r/emulation/comments/1kdpx87/ymir_a_new_sega_saturn_emulator_for_windowslinux/mqjy0rk/ amroamroamro's comment about chdman for CDs]</ref>)
 * '''Gain:''' Immediate
 * '''Tools Used:'''  chdman (included with MAME) ([https://github.com/DesertDoggy/CHDlite/ CHDlite)](Basically a CHDman wrapper with added functions), [https://play.google.com/store/apps/details?id=it.ottaviomiele.chd CHDroid] (for Android), [https://romtools.io/ ROM Tools] (web-based), [https://chd.emulationonline.com/ CHD Creator] (web-based, for converting bin/cue to chd)