Anyone using the swh-plugin - specifically mbeq successfully?

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DaveBullet1050
Posts: 3
Joined: September 28th, 2020, 8:07 pm

Anyone using the swh-plugin - specifically mbeq successfully?

Post by DaveBullet1050 »

hi all,

mbeq is a LADSPA multi-band (15) equalizer plug-in from Steve Harris.

The reason I'm posting here, is I can get the above plugin to work fine on my system (ArchlinuxARM - raspberry pi 3) with the following apps
mpg123
aplay

I can either route via alsaequal or direct LADSPA plugin in the asound.conf. Both work.

I can also get other plugins from swh-plugins (such as vynil and zm1) working fine via the above apps ... and also MPD.

However MPD (versions 0.20.19, 0.20.20, 0.21.22 and latest 0.22) play via mbeq - but it sounds like static combined with white noise. This is either via alsaequal or LADSPA direct.

I'm really stumped as to what is going on. the purpose of this post is to check what other mbeq users are out there, and if they are successful using it on their MPD systems (and what distributions they are using).

Thanks,
David.
max
Forum team
Posts: 1139
Joined: January 15th, 2013, 3:43 pm

Re: Anyone using the swh-plugin - specifically mbeq successfully?

Post by max »

I've never heard of this plugin.
DaveBullet1050
Posts: 3
Joined: September 28th, 2020, 8:07 pm

Re: Anyone using the swh-plugin - specifically mbeq successfully?

Post by DaveBullet1050 »

hi - swh-plugins is a group of LADSPA plugins by Steve Harris:
http://plugin.org.uk/
https://github.com/swh/ladspa

Has there been any change in 0.21 over 0.20 in the way ALSA devices are opened? I believe the auto_format setting in mpd.conf has changed in behaviour - as I have 2 systems. One requires "yes" to allow ALSA to change format (required by this LADSPA plugin from S16_LE to FLOAT_LE on my system), whereas the older build using MPD 0.20.19 doesn't seem to care ("no" and it works fine).

I'm not blaming MPD - it's a combination of library versions and Archlinux version that was working... and now after updating - is broken and I'm struggling to pinpoint it.

I might have to debug MPD in how it opens the ALSA device / driver to see what parameters are being set / passed.
max
Forum team
Posts: 1139
Joined: January 15th, 2013, 3:43 pm

Re: Anyone using the swh-plugin - specifically mbeq successfully?

Post by max »

If you want to know when things have changed/broken, do a "git bisect".
If you want to report a bug, use MPD's bug tracker. (That bisect would be VERY helpful in a bug report.)
DaveBullet1050
Posts: 3
Joined: September 28th, 2020, 8:07 pm

Re: Anyone using the swh-plugin - specifically mbeq successfully?

Post by DaveBullet1050 »

I resolved my issue.

I had to recompile mbeq_1197.xml/.c without optimisation. i.e. CFLAGS = -O0

Any higher level (e.g. -O1, -O2, -O3) causes mbeq to play "static" via MPD even though the same higher optimised mbeq_1197.so plays fine under other players / hosts (aplay / mpg123).

The above has been a real pain in the neck to troubleshoot. but that was my problem.

I've got no idea why the optimised version works under one host program but not another.
max
Forum team
Posts: 1139
Joined: January 15th, 2013, 3:43 pm

Re: Anyone using the swh-plugin - specifically mbeq successfully?

Post by max »

If compiler optimization changes the result, then the source code is buggy. Report the bug.
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