Pirate Radio after update from Jessie to Stretch instable

Support
20

Okay, I’ve done a bit of sleuthing into this and found that the issue lies with “dmix” rather than Pi VU Meter

Removing dmix from the equation gets audio output- including Pi VU Meter- up and running stably again.

Dmix was included in an attempt to allow multiple audio streams to output to the same device, which is not really an issue with Pirate Radio and probably something better solved with Pulse Audio (since it also solves the popping issue).

I’m not 100% sure what’s happening, but since the plugins in ALSA seem to share access to the same PCM channel buffer my hypothesis is that dmix is silently corrupting or trashing it somehow and that, in turn, causes Pi VU Meter to segfault when it tries to access it.

I am still testing this configuration on my own Pirate Radio setup, but so far it’s run for longer than 2 minutes and most fails have been at the 1-2 minute mark, so it looks pretty promising.

Now, an actionable fix for Stretch users? Just replce your /etc/asound.conf with the following:

pcm.!default {
        type plug
        slave.pcm "softvol_and_pivumeter"
}

ctl.!default {
        type hw
        card 0
}

pcm.pivumeter {
        type meter
        slave.pcm "hw:0,0"
        scopes.0 pivumeter
}

pcm.softvol_and_pivumeter {
        type softvol
        slave.pcm "pivumeter"
        control {
                name "PCM"
                card 0
        }
}

pcm_scope.pivumeter {
        type pivumeter
        decay_ms 500
        peak_ms 400
        brightness 128
        output_device phat-beat
}

pcm_scope_type.pivumeter {
        lib /usr/local/lib/libpivumeter.so
}

pcm.dsp0 pivumeter
1 Like