Re: [linux-audio-dev] linear resampling is crap ? (was: fast linear resampling on ARM - suggestions?)

From: <torbenh@email-addr-hidden>
Date: Thu Mar 30 2006 - 23:30:24 EEST

On Thu, Mar 30, 2006 at 04:34:43PM +1000, Erik de Castro Lopo wrote:
> torbenh@email-addr-hidden wrote:
>
> > On Wed, Mar 29, 2006 at 11:47:30PM +1000, Erik de Castro Lopo wrote:
> > > Tobias Scharnberg wrote:
> > >
> > > However, please do not use linear resampling; its just too crappy.
> >
> > urgh... i just switched my local copies of alsa_in and _out to linear
> > resampling, because SRC_SINC_FASTEST was eating CPU juice.
>
> Just out of curiosity, what kind of hardware are you running this
> on and what sort of performance would you find acceptable for your
> application. An estimate that provides:

ok... the program is a jack application, that opens an alsa pcm device
(obviously not the one, jackd is bound to) and either outputs or inputs
the sound.

>
> - input and output sample rates

input is usually 48000 or 44100 (the jackd samplerate)
outputrate depends on the soundcard used. 48k or 44k1 +- 10 Hz varying
with clock drift... and calculation of resampling factor in float.

i will improve the detection algorithm soon again.
so that the samplerate is changing slower...

> - samples per second per channel throughput wrt the output rate

realtime.

when the jack source clock is not very bursty (ie LAN or local)
2 channels take 7% cpu on an athlon xp 2000

with a bursty clock source from the internet the cpu usage in top is
much higher. like 20% or so.

a little too much for a soundcard IO :)

>
> would give me the best idea of what you are after.

i hope you get what i am after now. i am heavily exercising libsrc...

>
> Erik
> --
> +-----------------------------------------------------------+
> Erik de Castro Lopo
> +-----------------------------------------------------------+
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>

-- 
torben Hohn
http://galan.sourceforge.net -- The graphical Audio language
Received on Fri Mar 31 00:15:15 2006

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