Ok, so I started playing around with iTunes (this of course has nothing to do with the temptation of getting one (or both) of those lovely new apple products! Currently I am/have been ripping all my music via EAC to flac and started to research my options on how useful my flacs would be if I got a mac mini and/or ipod shuffle to play with.

Anyhow I did the honest thing and read through a few threads to see what options I had to make my flacs useful to iTunes. I found that I needed to convert my flacs to apple lossless files, and found a couple of suggested ways:

Use itunesencode and CLI diskwriter in foobar to go straight from flac -> alac
Use dbpoweramp to go from flac -> wma then throw them into iTunes to convert to alac

I remembered reading somewhere when alac first got released that some people reported it wasnt entirely lossless as the wav file appeared changed when decompressed. Anywho after playing around with a flac'ed Tool album and the itunesencode/foobar combo I was pretty suprised to see Lateralus come in 50 megs smaller when the diskwriter had finished! (approx 450 mb vs 400 mb) I also remembered reading that alac was no great improvement/similar to flac so was a little curious at this result!

So I took track 1 The Grudge and used the two methods above to convert to alac, then decompress and compare the md5's of the wav files.

Original flac
01 - The Grudge.flac 55,733KB 1772742DB4C782158CF5D8698259B868
01 - The Grudge_flac.wav 88,936KB 1703E5E22FAC833008BB41C5EEE1BCF2

Flac to WMA
01 - The Grudge.wma 53,906KB 0633E33213A127C4E27E7A95C02091FB
01 - The Grudge_flac_wma.wav 88,936KB 1703E5E22FAC833008BB41C5EEE1BCF2

Flac to ALAC using itunesencode and foobar
01 - The Grudge.m4a 49,007KB DDB4342230929525FBCF0351CC9D974F
01 - The Grudge_flac_alac.wav 88,936KB EDBEDC4D6F6A050BF1436DD9C6A4C873

Flac to WMA to iTunes
01 - The Grudge.m4a 55,600KB 8BAA4175357E75A45CC9D35775E15459
01 - The Grudge_flac_wma_alac.wav 88,936KB 1703E5E22FAC833008BB41C5EEE1BCF2

Notice how the itunesencode ALAC is approx 6 megs smaller than the WMA -> iTunes ALAC! However, all the decompressed wav files came out at the exact same file size which again was kinda confusing, as I figured something had gone pretty wrong the itunesencode process considering the file size. But the MD5's of the wav files confirmed the worst, its the only one that doesnt match up.

Edit: out of interested I used EAC to do a wav compare between 01 - The Grudge_flac_alac.wav and the original 01 - The Grudge_flac.wav. It found different samples at 0:00.00.337 - 0:08:36.266

So to end a long (sorry) story, any idea as to why this method yeilds this inconsistent result? Bit sad as it definately seemed like the best/easiest option. Im also kinda worried about the amount of times I saw people recommend this method here and say they have deleted their flacs now they are all converted over to apple lossless

Hopefully its just something isolated to me? Any similar experiences/anyone replicate this?

Ugh, after the wav compare thing I thought I would acutally have a listen to the song (what, abx two lossless files!? this sounds like fun..) to see if I could hear anything different. Well what do you know it sounded a lot quiter... so then I smack my head and think about when I set Use Replaygain in my diskwriter settings when I was doing some other transcoding...

So I turned this off and confirmed it was, as suspected my own stupid fault. Trap for beginners there! What a waste of time that all was