> do I really need to update my current CHD files ?
I don't know why anyone would update all their samples or CHD files for a "u" version. From my understanding, "u" releases are like development snapshots between major releases. It's entirely possible that this new 7-zip and FLAC stuff may change before MAME 0.146 is released.
Though, I guess someone has to be the guinea pig to try this stuff out and find bugs before the next release, so carry on.
> also, I used chdman to update the file and it got bigger... I thought this new header
> version would make CHD files smaller.
My understanding is that there is a tiny amount of overhead to store the information about what compression algorithm to use for each block, however that should be negated by the higher compression ratios of the new algorithms. I guess it's possible, but not likely, that the best compression algorithm for each block ends up being "zip" (like in the v4 CHD) and the overhead makes the file larger.
Someone should convert ALL the CHDs and post a list of before/after sizes.
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