Messages in this thread | | | Date | Wed, 14 Apr 2004 21:29:51 +0200 (CEST) | From | Pascal Schmidt <> | Subject | Re: Using compression before encryption in device-mapper |
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On Wed, 14 Apr 2004, Guillaume [iso-8859-15] Lacôte wrote:
> You are right that in this very case, the per-bit entropy will be > (1 - 1/(1+1/8) ) ~ 12% lower than in the original text. The point is > that this case (which has nothing to do with the case where a text can > be well compressed or not, this is the worst _relative_ performance of > dynamic versus static encoding) does not happen "too often".
I was only pointing out a corner case where your argument doesn't hold. I completely agree that it is rather unlikely to happen with real world data.
There is one exception, though: data that has already been compressed before on a higher level; by the user, for example. However, in that case you could say that what you're trying to accomplish has already happened before during the original compression run.
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