Arch Linux

apolyonn

Member

Registered: 2013-05-21

Posts: 46

ALSA : LADSA plugin syntax help

Hey all,

I just set-up my .asoundrc file on a new build.  Using the declip plugin, in my alsa config, is producing some sound in the left channel, and only silence, interrupted by repetitious clicks, in the right channel.  Using Audacious, which ships with a GUI interface for using LADSPA plugins, everything sounds fine. 

I'm not really sure what I'm doing wrong.  Any help would be appreciated.

~/.asoundrc

pcm.!default {
	type plug
	slave.pcm "ladspa"
	hint {
		show on
		description "Actual Default"
	}
}

pcm.ladspa {
	type ladspa
	path "/usr/lib/ladspa"
	channels 2
	slave.pcm "hardware"
	hint { show off }
	plugins {
		0 { id 1207; policy none; }
		1 { id 1195; policy none; }
	}
}

pcm.hardware {
	type plug
	slave.pcm "hw:0,0"
}

Output of "analyseplugin declip_1195.so"

    Plugin Name: "Declipper"
    Plugin Label: "declip"
    Plugin Unique ID: 1195
    Maker: "Steve Harris <steve@plugin.org.uk>"
    Copyright: "GPL"
    Must Run Real-Time: No
    Has activate() Function: No
    Has deactivate() Function: No
    Has run_adding() Function: Yes
    Environment: Normal or Hard Real-Time
    Ports:    "Input" input, audio, -1 to 1
         "Output" output, audio, -1 to 1

emeres

Member

Registered: 2013-10-08

Posts: 1,570

Re: ALSA : LADSA plugin syntax help

Try adding slave.rate 44100; to your default pcm. It seems those plugins (or at least one of them) need to be driven with that frequency (maybe 44,1 kHz is hardcoded). Otherwise your asoundrc seems to be fine, although I did use a software pcm to test this setup and not directly hardware.

apolyonn

Member

Registered: 2013-05-21

Posts: 46

Re: ALSA : LADSA plugin syntax help

Try adding slave.rate 44100; to your default pcm. It seems those plugins (or at least one of them) need to be driven with that frequency (maybe 44,1 kHz is hardcoded). Otherwise your asoundrc seems to be fine, although I did use a software pcm to test this setup and not directly hardware.

Thanks for your help.  While changing the samplerate didn't affect anything, setting the policy to "duplicate" for both seemed to fix the issue.  Sound is great even at 96kHz