What does RVZ compression block size affect?

[zachThePerson]

I've been doing some experiments with different RVZ compression settings, and one thing that doesn't seem to change much is the block size. All games I've tested it on block size doesn't seem to affect the final size of the game at all. I know with other compression software such as 7z, block size affects how easy it is to pull a single file out of the archive, but how does that affect dolphins performance?

Do smaller block sizes mean faster loading? Larger block size faster loading? Should I just leave it default, or should I change it based on the game?

[JosJuice]

(07-06-2020, 04:13 AM)zachThePerson Wrote: I know with other compression software such as 7z, block size affects how easy it is to pull a single file out of the archive, but how does that affect dolphins performance?

It's about the same in Dolphin. The larger the block size is, the slower it is to seek in the disc image, so you should avoid making it too large. I usually leave it at the default, but if you use Zstandard (not if you use one of the compression algorithms marked "slow"), increasing it should be fine. Dolphin blocks you from selecting the truly unplayable block sizes anyway.

[zachThePerson]

(07-06-2020, 04:18 AM)JosJuice Wrote: It's about the same in Dolphin. The larger the block size is, the slower it is to seek in the disc image, so you should avoid making it too large. I usually leave it at the default, but if you use Zstandard (not if you use one of the compression algorithms marked "slow"), increasing it should be fine. Dolphin blocks you from selecting the truly unplayable block sizes anyway.

Ok, I'll just leave it at default. Is there any advantages to changing the size though? Like hypothetically speaking, if a specific game was loading slow, would changing the block size have a noticeable affect?

[JosJuice]

(07-06-2020, 04:54 AM)zachThePerson Wrote: Is there any advantages to changing the size though?

Increasing the block size makes the file size smaller.

(07-06-2020, 04:54 AM)zachThePerson Wrote: Like hypothetically speaking, if a specific game was loading slow, would changing the block size have a noticeable affect?

Decreasing the block size would likely help in that case.

[k0pp0]

This is a great feature, however it would seem that all of my ISO's aren't compatible. Gamecube ISO's have worked fine though

[JosJuice]

(07-06-2020, 10:30 PM)k0pp0 Wrote: This is a great feature, however it would seem that all of my ISO's aren't compatible. Gamecube ISO's have worked fine though

If Dolphin doesn't let you convert a disc image, it is not actually an ISO. You are probably using a format like WBFS or CISO, both of which are incompatible with Dolphin's converter.

[cheap plastic]

Does converting an ISO to RVZ have any downsides? Like just performance in game? I have copies of my games in both formats, and I'm not sure if I should just convert them all to RVZ or not to save on storage. I don't care for load times, but if it makes the game itself run worse, (framerates and stuff) I'm not sure if I would commit to it.

[AdmiralCurtiss]

Load times would be the only plausible difference, and even those are likely not impacted due to the asynchronous way Dolphin loads data from the game file. And you can always convert back to ISO if you need to for whatever reason.

[Klemc]

Default settings are meant for all games to be palyable i presume.

Quote:If a specific game was loading slow, would changing the block size have a noticeable affect?

Quote:Decreasing the block size would likely help in that case.

I'd like to know about the "no compression" in comparison... any advantage, because it makes ISO smaller enough for me ! And about block siz behvior in that case, always smaller better in case of hypothetical slow loading ?

Paper Mario GC ( 1 459 978 240 octets ) :
616 906 724 octets - No compression
617 298 464 octets - No compression 32ko
616 774 680 octets - No compression 2mo
//
353 209 700 octets - Default
355 096 308 octets - Default 32ko
337 557 216 octets - Default 2mo
363 273 768 octet - Default level 1
348 445 984 octets - Default level 10

And so, the level 22 doesn't affects decompression ? 22...

Pandora Tower ( 4 699 979 776 octets ) :
2 647 027 088 octets - Default
2 705 087 756 octets - level 1
2 615 256 196 octets - level 22
3 181 701 612 octets - No compression

[Klemc]

I'd like an answer because i want to compress my games as soon as... thanks.