[pulseaudio-discuss] location of pa-equalizer default config and presets

Jason Newton nevion at gmail.com
Sat Jul 29 03:49:46 UTC 2017

On Fri, Jul 28, 2017 at 8:46 PM, Jason Newton <nevion at gmail.com> wrote:

> Hi Bernhard,
> Sorry for the lag in getting back to you, I've got many things I'm
> juggling these days and for some reason my alerts for PA don't work all the
> time....
> Anyway - Tanu gave you an accurate reply.  Your confusion is due to the
> ecosystem of the equalizers coming into popularity in the same timeframe,
> and at some point the ladspa one became more popular - but then many people
> conflated the two and propagated based on the names, especially across
> forums.
> A couple of points:
>    - qpaeq does not store any profiles, although I think it should have
>    the feature to upload CSVs/ lists of tie points.
>    - The database the equalizer uses to store profiles is whatever the
>    database format pulse decides at build time, but ultimately binary tuple
>    store like bdb.  It uses pulse's api to get and put stuff to that database.
>    - You can, like qpaeq does, speak to the sink over dbus to add or
>    remove profiles, including specifying control points in binary.  Have a
>    look at the equalizer_handle_seed_filter function which receives and
>    processes such dbus messages, for any or all channels.  This is how you
>    should do what you're asking to do.
>    - The dbus routines/callbacks (currently under line 1328 in
>    module-equalizer-sink.c) would be helpful to review to see the different
>    methods available for manipulating the equalizer through either improving
>    qpaeq or having a separate utility for importing profiles.
>    - Be aware that the filter rate and sample rate are different, with
>    the filter sampling rate being higher (next power of 2) and renormalize
>    your control points as such before handing it over to the server and that
>    every profile is expected to be this filter rate size big. I should have
>    had an optional boolean to do this on the server, but I didn't need it at
>    the time.
> It shouldn't be too much work (like 50-100 lines of python) to hack
> together a dbus based upload/import script for such profiles.
> -Jason
> On Wed, Jul 26, 2017 at 12:03 PM, Bernhard Landauer <oberon at manjaro.org>
> wrote:
>> On 26.07.2017 20:58, Tanu Kaskinen wrote:
>> My answer was based on reading the source code, and it seemed like
>>> module-equalizer-sink stores some database in
>>> ~/.config/pulse/equalizer-presets, and based on the file name, that
>>> seemed like the place where the presets live.
>>> I now looked at the contents of the files in
>>> https://github.com/rsommerard/pulse-presets and it's clear that those
>>> preset files aren't used with qpaeq/module-equalizer-sink. The database
>>> that module-equalizer-sink uses is not in text format, but the
>>> rsommerard presets are text files. The files contain the string
>>> "mbeq_1197", which is an identifier for a ladspa eq plugin. Apparently
>>> the presets are meant to be used with some program that sets up module-
>>> ladspa-sink in pulseaudio. I don't know what program that is.
>> Right. My actual question is still not answered.
>> I need to preconfigure qpaeq and the files in ~/.config/pulse are in fact
>> not doing the job. Deleting them does not remove an existing config and
>> providing them does not supply them ... So how does it really work?
>> _______________________________________________
>> pulseaudio-discuss mailing list
>> pulseaudio-discuss at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Whoops - sorry for the previous top post.

Also, qpaeq can show you a bit of how to speak with the equalizer in a
separate script.

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