On Tue, 13 Aug 2024, Fons Adriaensen wrote:
Below is a description of the configuration I'd want. If anyone knows
how to do this (it shouldn't be that difficult)
It shouldn't be that difficult.... unfortunately, pipewire is pretty much
idiot proof.... or good for idiots. I don't say this as a slight against
the PW dev (team?), it is not easy to make things idiot proof while still
being mostly very usable. Just that the design goals don't align so well
with professional audio use all the time.
2. Currently the ALSA Jack plugin is used to route audio from
web browsers etc. to Jack. PW may take over this role but
that is not a strict requirement.
You may wish to leave pipewire stopped and continue to use alsa jack
plugins
3. PW will be started manually when required, and I don't expect
that will happen very often. It may remain running when no longer
needed but shouldn't interfere. It will be used to connect apps
to Jack as in (2), or those that even don't support ALSA, or
maybe to route audio from Jack to Bluetooth etc.
These are not pipewire design goals, I do not know how well pipewire
bridges to jackd. There is not a way that I have found to be able to
configure a PW-Jackd bridge as pulse used to have. Just sort of an on/off
switch where PW decides how many ports bridge the two in which directions
based (I think) on the number of system:* ports. I would guess auto
connect happens too.
4. All Jack ports created by PW should be permanent and exist
as soon as PW is started, so they can be manually connected
and remain connected even when not in active use.
This is not a design goal of PW. However, it is possible to create psuedo
or passthrough PW objects that are static and use them as default desktop
"devices". As these are config file setup, they appear when PW starts.
5. PW should never ever access the sound card used by Jack,
not even if accidentally started when Jack is not running.
It must not force Jack to use dbus in order to get access
to that card. It may manage other sound cards, but preferably
only those explicitly listed.
This is not a design goal of PW. PW does not even seem to have the option
as pulse did to configure a device as off. Instead it merely does not
spend any cpu running that device if there is no connection. I do not know
if that means the device is "opened" (and in use) or not
6. PW must never ever interfere with Jack in any way - making
connections, trying to change the period size, etc. Its only
role is to be a well-behaved Jack client.
Supposed to be possible. The idea is to use jackd as a device for pipewire
where PW will act only as a client, accepting jackd's rate, period and
periods as they are. I have never successfully acheived this but it has
been a while since I tried.
7. I do not expect anything 'automatic' to happen when things
are plugged in or out.
PW will not be started by plugging in a device. but if it is running I do
not know if the udev detection can be disabled or if pw can be made usable
if udev is disabled.
8. The PW configuration should be done in such a way such that
it can't be modified by drop-in files from the system package
manager. All configuration should be manual and explicit, and
easy to verify without having to scan a myriad of files and/or
directories and trying to understand how they interact. This
is just basic security.
Config files are pretty much standard linux. The package uses /usr/share/*
for package default settings which may change but these can be overridden
with system wide settings in /etc/* which can be overridden with user
settings in ~/.config/*. So if all config options are set one way or the
other in ~/.config/, a new package config file will not change anything
unless config options are added or removed in a new version. New config
options should not happen too much now that v1.0 has happened.
I grew up with analog components where one could always see where the wire
went and plugs were not likely to jump out of one place and connect to
another, nor were pedals someone brought into the room likely to just find
a conveient place in my signal chain to insert themselves. Pulse and now
pipewire are more like the ghettoblaster.....
PW has a design goal of replacing pulse, ALSA direct connections and jackd
all at the same time. It does this well enough for many people but does
not cover everything. So far, it has been fine (if I don't look too close
at the very cluttered jack graph) for my use but from the little I know
about some of your projects I expect it will not meet all your needs.
Currently, I am not doing enough with computer audio as it matters.
Some things I would like to see in pw:
jackd-pw bridge:
as many as needed
ports=number and direction
pw side buffer size
auto connect=disable
devices:
Jack graph master device (or media clock master)
That can't be changed by the desktop GUI. That is
this is different than the default i/o device
device ignore
The device doesn't show up on the pw or jack graph
and is not opened or locked
new device ignore or active devices list
imutable device names
At least so long as the same device is plugged into the
same physical USB port (many usb devices do populate
the serial number field)
User settable device names
I could list more and maybe by now some of these are already possible.
Nicer docs would help a lot but really the docs are not that bad either.
--
Len Ovens
www.ovenwerks.net
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