Re: [rtcweb] Performance of H.264...

John Leslie <> Wed, 20 November 2013 19:26 UTC

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Date: Wed, 20 Nov 2013 14:25:50 -0500
From: John Leslie <>
To: Maik Merten <>
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Subject: Re: [rtcweb] Performance of H.264...
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Maik Merten <> wrote:
> Am 20.11.2013 18:52, schrieb Bernard Aboba:
> There's much to be said about PSNR as means for comparing image quality. 
> There's also much to be said about PSNR as means for conducting 
> cross-codec quality assessments.
> And little of it is pretty.

   I don't think we need to pick on the authors here -- they were quite
clear about what they were doing.

   IMHO, the point to take away from the paper is that _neither_ H.264
nor VP8 are considered "current" first choices.

   The paper basically showed _by_how_much_ H.264 falls short of current

> I always chuckle when I see x264 being given the "--tune psnr" 
> parameter. Even core developers of x264 have strong opinions on this: 

   Fun reading...

   But we _don't_ need any more lengthy criticisms of comparisons right
now. We _aren't_ going to drop everything and switch to H.265 as MTI --
or any other state-of-the-art codec.

   I fully agree that both H.264 and VP8 deserve SHOULD status; and
I agree H.261, being good enough for sign-language reading, looks like
the right fallback.

   H.261 is certainly easy enough to "implement" and deploy; and I'll
bet 80%  of us are ready for the question...

John Leslie <>