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Thread: segfault in aplay using ladspa-filters in .asoundrc

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  1. #1
    Join Date
    Oct 2008

    segfault in aplay using ladspa-filters in .asoundrc

    hey all,

    my external active frequency crossover just broke down yesterday, the right high frequency channel is dead.

    some time ago i read some article about using ladspa to split off the subwoofer channel - so i hought i can do that as well and split up 2 channels to 6 and filter them, all before the sound even gets translated to an analogue signal.

    so i made a test setup - but "it doesn't work" - to be precise, aplay crashes with a segfault when i try to handle more than 2 channels.

    first of all, the working .asoundrc configuration:

    pcm.split_channels {
         type plug
         slave.pcm filter
         slave.channels 2
         ttable {
             0.0     1       # hi left
             1.1     1       # hi right
    #         0.2     1       # mid left
    #         1.3     1       # mid right
    #         0.4     1       # lo left
    #         1.5     1       # lo right
    pcm.filter {
        type ladspa
        slave.pcm finish
    	#slave.pcm "plughw:0,0";
    	#slave.pcm surround51
        path "/usr/lib/ladspa"
        channels 2
        plugins {
            0 {
                id 1098 # Identity (Audio) (1098/identity_audio)
                policy duplicate
                input.bindings.0 "Input";
                output.bindings.0 "Output";
            1 {
                id 1904
                policy none
                input.bindings.0 "Input"; #left
                output.bindings.0 "Output";
                input {
                    controls [ 200 0.755 ]
            2 {
                id 1904
                policy none
                input.bindings.1 "Input";#right
                output.bindings.1 "Output";
                input {
                    controls [ 200 0.755 ]
    pcm.finish {
    	type plug
    	slave.pcm "hw:1,0";
    so i send the split_channel result to filter, and then to finish. this setup works.

    when i switch the 2 channels in split_channels to 6 or some other value [2..6] (leaving the value in filter as it is) results in a complaint about bad settings (as it should)

    when i adjust the value in filter as well i get a segfault in aplay:

    ab@pcab:~$ aplay -v -D split_channels daslied.wav
    Playing WAVE 'daslied.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
    Segmentation fault

    so, what might be the problem? the card is a cheap C-Media 5.1 card... a driver problem maybe?

    btw, my soundcards keep switching places (i have 2 - 1 onboard (even worse) and 1 pci) and aplay -l shows them in random order after reboot... how to fix that?

    attached you'll also find the original files...

    thanks for all help
    Attached Files Attached Files

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