[FFmpeg-devel] Testing Inexact Data

Loren Merritt lorenm
Thu Jan 24 07:48:12 CET 2008

On Tue, 22 Jan 2008, Mike Melanson wrote:

> I am at the point with the FATE server ( http://fate.multimedia.cx/ )
> where I want to start testing data that is not defined to be bit exact.
> Michael recommended that I should use the tiny_psnr utility. Sounds
> great, except that, well... I'm not very good at math and I don't know
> what the numbers actually mean. :)
> I decoded surge-2-16-B-.mp3.mov from:
>   http://samples.mplayerhq.hu/mov/qtaudio/
> I decoded the file to WAV on x86_32 and PPC machines and then ran:
> $ tiny_psnr mp3-ppc.wav mp3-x86.wav 2 0 0
> stddev:  0.53 PSNR:101.81 bytes:2322432
> 1) What are good numbers vs. bad numbers in this case? And for other cases?


But AC3 contains randomness, so I'm not sure whether that 78dB was 
produced only by inexactness.

--Loren Merritt

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