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

[Måns Rullgård]

Loren Merritt <lorenm at u.washington.edu> writes:

> 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.)

Speaking of PSNRs, how much is the overhead of calculating these?  If
I only want encoding speed, can anything be gained by disabling some
calculations?

-- 
Måns Rullgård
mru at mru.ath.cx

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