Re: [Alsa-user] Alsa-lib and ladspa

[<re...@ho...>]

 

> -----Ursprungligt meddelande-----
> Från: Mårten Gustafsson 
> [mailto:mar...@ho...] För re...@ho...
> Skickat: den 27 februari 2009 00:32
> Till: 'als...@li...'
> Ämne: Re: Alsa-lib and ladspa
> 
> > I read about bug fixes for alsa when using ladspa plugins and 
> > multi-channel audio. My setup is kernel 2.6.21.7 with alsa-lib 
> > (1.0.17a). However, I'm wondering what if any other alsa 
> packages I'm 
> > required to upgrade in order for ladspa multi-channel 
> plugins to work?
> > Specifically, I'm attempting to create a 2.1 low pass filter (see 
> > 
> http://alsa.opensrc.org/index.php/Low-pass_filter_for_subwoofer_channe
> > l_ (HOWTO)). I'm attempting to use the referred to asound.conf from 
> > the low pass filter HOW-TO but I've noticed the following:
> >
> > 1) The upmix_20to51 device is listed as type "plug" but 
> seems to need 
> > to be "route" ? I use "plug" I get the error "pcm_params.c:170:
> > snd1_pcm_hw_param_get_min: Assertion 
> `!snd_interval_empty(i)' failed"
> > 2) If I directly use the upmix_20to51 device, but change 
> the slave to 
> > "plughw", I get the expected 3 channel output
> > 3) If I directly use the lowpass_21to21 device, but change 
> the slave 
> > to "plughw", low pass filtering works
> > 4) If I directly use the upmix_21to51 device, but change 
> the slave to 
> > "plughw", I get the expected 6 channel output
> >
> > So my plug-in chain seem to have issues communicating with 
> each other?
> > Anybody with similar experiences, thoughts, or comments? It 
> would be 
> > very appreciated.
> 
> Hi Peter
> 
> Did you ever solve this? I am having the same problem. I have 
> tried two sound cards with the same result. I am using the 
> latest available alsa rpms for opensuse 11.1 on an amd64 box.
> 
> Thanks
> 
> Mårten Gustafsson

I solved the problem by replacing the "plug" plugins with "route" and
"lfloat" plugins. There is most certainly a bug in "plug" plugin.