[x264-devel] Re: [PATCH] PSNR averages

[Laurent Aimar]

On Sat, Aug 07, 2004, Loren Merritt wrote:
> x264 takes the arithmetic mean of frame-wise PSNRs to produce an
> overall PSNR. This is meaningless. (Extreme case: what do you do with a
> frame with no error? (infinite PSNR))
> This patch corrects it to calculate PSNR from the mean squared error.
> 
> I also replace "PSNR/Size" (which is similarly meaningless) with
> "MSE*Size". This quantity is probably closer to what someone wants to
> measure when they think of "PSNR/Size". It also tends to be relatively
> constant for a given video over a wide range of QPs.)
 You are right mean PSNR is a bit meaningless, thanks for your patch :))

 Now x264 will compute mean PSNR (as before, used by the JM), average
and global PSNR.

 Average/global are computed over the whole picture (ie YUV), I hope
it's ok, if not I will change it to do it over each plane too.

-- 
fenrir

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