Dolphin Compression

[shuffle2]

OK time to set some things straight:
When compressing GC games, dolphin just compresses the image sector by sector. This means no data is changed. This also means that you will only see space savings when the game has compressible areas; if the disc has real dummy data - which is to say that it is just random bits, and is not listed in the file table - then that area won't compress well.

On the other hand, Wii images are almost fully encrypted, so the data appears to be incompressible. To get around this, dolphin calculates which areas of the disc are not used in the filesystem, and fills them with 1s. This makes the unused areas extremely compressible. (The "scrubbed" image is then compressed in the same way the GC image is, above).

People have problems with the SSBB image because they download the "DVD5" version. It's not dolphin related.

[ugoo]

ok then so the normal DVD-9 version does not have that problem

[fagoatse]

I've used this tool on my all games(~15) and it works great. Big kudos for anybody who wrote it

[Zhelkus]

Sorry to bump an old thread, I just wanted to get the facts on this feature since there's no wiki

Dolphin's compression does... scrubbing and compressing or just compressing? Is the compression lossless (will I get the same CRC32 or MD5 after I decompress it)?

I just tried compressing F-Zero GX and I got the exact same file after compress-decompress.

I want to know how this works in case it proves to be better than scrubbing my images and potential damaging them.

[cmccmc]

for gamecube games it just compresses it and will be the same when uncompressed
for wii games they are scrubbed and then compressed so they will be different after they are uncompressed

[Zhelkus]

Thx for the quick reply

One more thing: is the scrubbing dangerous? What are the risks of scrubbing a Wii image besides accidentally touching the sensitive part? Are there games that rely on the noise at the end of the disc?

[cmccmc]

not any that i know of

[Zhelkus]

kool thx!