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Wavpack compression ratio with mono music on CD
BoraBora
post Oct 13 2005, 22:46
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First of all, I'd like to thank Bryant for this wonderful codec. I switched to Wavpack for my whole collection (2000+ CDs) since the 4.0 release and I never looked back. cool.gif The compression/speed ratio is a killer, and the ApeV2 tags don't hurt either. tongue.gif

However, while running some general tests on lessless codecs, I stumbled on some results that may be of interest. I happen to listen to a lot of old mono popular music on CD (so technically it's stereo, but you see what I mean) and I was surprised to see Flac -8 frequently outperforming Wavpack -h, which to my small knowledge never happens with stereo music. Something weird, too: sometimes, Wv -f outperforms by a very slight margin wv default. Here are some numbers:

* On 5 out of 10 CDs tested, Flac -8 outperforms Wv -h (actually, Flac -5 does too)

* The biggest gap is happening with a recent Presley remaster where Wv -h does 32,52% while Flac -8 does 28,09%.

* On 2 out of these 10 CDs, Wv -f outperforms by a slight margin Wv default, and on 1 of these CDs even Wv -h! (-f = 42,01%, -n = 42,76%, -h= 43,30%).

I uploaded an Excel sheet on my site with detailed results. If you have any questions, please let me know. smile.gif
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Drenholm
post Oct 15 2005, 13:56
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I also disagree. It may well be a consideration for WavPack 5 but I don't think it'd be good to break compatability any sooner.

What I don't understand is why WavPack performs so bad on these almost-mono files. Is this, as I asked earlier, some kind of joint-stereo problem? Bryant, an explanation for a dumb person would be appreciated. biggrin.gif

Anyway, downmixing first is not an idea solution for files that are 'almost' mono as, technically, you are changing audio data, right?
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