[FFmpeg-devel] [RFC] Default audio resampling parameters

Michael Niedermayer michaelni at gmx.at
Tue Aug 7 04:21:56 CEST 2012


It seems our default audio resample parameters are maybe not so good.

if you downsample a frequency sweep (for example
you can find some input test signals at:
http://src.infinitewave.ca/TestSignals.zip )

you will notice there is significant attenuation before the nyquist
the following works (much) better in that respect:
-af aresample=osr=44100:filter_size=256:cutoff=1

the question is what values for cutoff and filter_size are reasonable
as defaults ? (larger filter_size makes the thing slower so we would
want to stay on the small side of what sounds nice)

are there some people with good ears around who would be happy to do
some double blind tests ? (downsampling some music and checking with
which parameters it actually sounds best and where the differences
become inaudible)
because really it doesnt help us to select values that are good in
some limited set of mathematical tests when they maybe dont sound
good to humans.


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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