[MPlayer-users] PSNR Questions

[Ian]

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D Richard Felker III wrote:

> Huh?? This is nonsense. You can't compare PSNR relative to two
> different reference 'signals'. When encoding, the source is considered
> the signal, and the difference between the encoded picture and the
> source is the noise, so the source has infinite PSNR automatically.

OK, this is the first time I've seen it stated, a formula would be nice 
too, but in any case see below . . .

> Yes, theoretically. Computational issues might make it come out
> different tho.

Regardless, since in my experience better quality material (ie. the 
originals!) has a lower PSNR than the copies, I can't take it seriously. 
  Obviously your experience is different.

> Huh?? Do you even know what PSNR means??

Can't find the reference (it seems to be unavailable ATM), but I thought 
it was peak signal to noise ratio.  I can't be that much of a dimwit if 
I'm using the encoder successfully, now can I? ;)

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Ian Smith
Worst . . . signature . . . ever !

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