Gamecube disc filler data

[Dammit9x]

So you know that GC discs have random filler data inserted to fill up whatever part of the disc is unused by the game data. The data, being random, compresses very poorly and for archival it's best to get rid of it. My question is, how is it done? I have some gamecube .ISOs that I want to compress smaller.

[General Plot]

Originally Posted by Dammit9x

So you know that GC discs have random filler data inserted to fill up whatever part of the disc is unused by the game data. The data, being random, compresses very poorly and for archival it's best to get rid of it. My question is, how is it done? I have some gamecube .ISOs that I want to compress smaller.

Dolphin has a GCM shrinker, only take caution when using it, as it's still not perfect yet, and can corrupt your image files. I'd recommend keeping them backed up first, just in case.

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[Silenus]

I think that this belongs to the gamecube section of the forums.

The emulator dolphin comes with a .gcm shrinker, I think it does what you said,get rid of the blank data and compress the game.

Go download dolphin and try it.

Edit: You beat me to it General.

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[Dammit9x]

Yep it worked. And I used Dolphin to confirm that they were still bootable. So I guess Dolphin is good for something.

Originally Posted by Silenus

I think that this belongs to the gamecube section of the forums.

Yeah I put it here cause I knew it would get more eyeballs.

[Dammit9x]

Wait a sec... am I to understand that the only difference betweeen iso and gcm is just that gcm has been shrunk?

[Kazuya Mishima]

Exactly, as a rule an iso is the exact image of the disc but it's in the hard drive. The gcm takes aways the parts that are not used in the game itself.

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[mr.saraiva]

There's a better utility avaible, it's called "GCM Utility". Get it at:
http://forums.maxconsole.net/showthread.php?t=7413

[Clements]

GCM is the agreed extension for the streamed file. There is no difference between ISO and GCM in this case.

I use NTFS compression to retain the clean GCMs and save disk space (like I do for the PSX images). In most cases, the junk data compresses fine:

Attached Images

GCM.PNG (27.6 KB, 28 views)

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