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

[Jason Newton]

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?
>
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