On Mo, 2007-01-08 at 17:47 +0200, Sergei Steshenko wrote:
> On Mon, 08 Jan 2007 10:43:38 +0100
> Sebastian Schäfer <[EMAIL PROTECTED]> wrote:

> > Adjusting the buffer size really did the trick!
> > It's done by echoing something in /proc/asound/card0/pcm0p/sub0/prealloc
> > The maximum value is given in prealloc_max.
> > Now I just have to try and adjust the plugin for use with 48 kHz.
> > 
> > (Wish for the next release: A config line where the sample rate to be
> > used can be given and bands too close will automatically get thrown out
> > or whatever. At least if that is possible, of course.)
> > 

> Sebastian, where do I find the value of prealloc_max ?
> Only in ALSA source ? Or in kernel source ?
> 
> Thanks for the info, now I myself know how do it ! :-)
> 
prealloc_max is also a file in /proc/asound/card0/pcm0p/sub0

> 
> Regarding
> 
> "
> A config line where the sample rate to be
> used can be given and bands too close will automatically get thrown out
> or whatever. At least if that is possible, of course.)
> "
> 
> - this is very difficult at best - the problem is, as I wrote, that
> when the Perl code used to actually the generate the "C" code is
> run, sample rate is not yet known.
> 
> And in the definition of LADSPA each time sample rate changes the
> plugin should be reinstantiated, that's because there can
> be things (DSP coefficients, delay line lengths, etc.) which are
> functions of sample rate.
> 
> Again, joining frequencies at runtime doesn't seem to be an option,
> because this means joining control ports, i.e changing their number,
> which is not possible, or blocking them, which adds to code complexity.
> 
> As a compromise I can add to the Perl code something like
> expected_sample_rate entity, expected_fft_length, so the code will try to 
> adjust bands/ports according to the two entities.
> 
> However, still, if, say, the bands are as close as possible at
> 48kHz, and suddenly the plugin is used at 96kHz, it will fail.

That's exactly what I meant :-)

BTW: As I tried to get it working with 48 kHz and commented out the band
between 20 and 40 Hz, I figured out that without that one, the equalizer
works even with 96 kHz (I tried different sample rates using mplayer
-srate [Hz] file.avi), but unfortunately mplayer crashed when using
22050 Hz. I did not further investigate this, as I normally do not play
files with such a sample rate.
> 
> Regards,
>   Sergei..
> 
Regards,
Sebastian


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