Re: [linux-audio-user] resampling question

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Subject: Re: [linux-audio-user] resampling question
From: Erik de Castro Lopo (erikd-lad_AT_mega-nerd.com)
Date: Wed Oct 08 2003 - 01:23:02 EEST


On Tue, 7 Oct 2003 23:51:07 +0300 (EEST)
Tommi Sakari Uimonen <tuimonen_AT_cc.hut.fi> wrote:

> Hi. If I want to resample from 96khz to 48khz, what would give the best
> result: use libsamplerate, or just drop off odd (or even) samples?
>
> I guess the libsamplerate and any of its interpolations would cause some
> digital garbage anyway,

Sample rate conversion using libsamplerate's SRC_SINC_* converters gives a
signal to noise ratio of 96dB or better. Yes there is some digital garbage
but its probably less than the noise picked when an instrument is recorded
with a microphone.

> or are they intellectual enough to detect that the
> rate is halved and just perform a drop off?

On most normal signals, dropping every second sample will sound considerably
worse than what libsamplerate does. I suggest that you read up on sampling
and aliasing for an explanation of why.

Erik

-- 
+-----------------------------------------------------------+
  Erik de Castro Lopo  nospam_AT_mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
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serve several meals on it every week." -- Anthony Minkoff


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