Dne 23. 02. 20 v 10:00 Tanu Kaskinen napsal(a):
On Sat, 2020-02-22 at 08:53 +0200, Tanu Kaskinen wrote:
On Sun, 2020-02-16 at 18:38 +0100, Jaroslav Kysela wrote:
Dne 16. 02. 20 v 11:06 Tanu Kaskinen napsal(a):
On Sun, 2020-02-16 at 11:42 +0200, Tanu Kaskinen wrote:
+ pulseaudio-discuss@xxxxxxxxxxxxxxxxxxxxx
On Sat, 2020-02-15 at 17:25 +0100, Jaroslav Kysela wrote:
Actually, I am also trying to resolve the description of the speaker
configuration. It may not be only enough to give the PCM device, because we
don't know, if user connected the stereo or surround speakers to the sound
card output for example. I play with an idea to add device variants to UCM,
but the question is, how we can map this to pulseaudio profile/port schematics.
My quick idea is to export those variants via the verbs, so the exported verb
names might look like:
HiFi:Speaker-Stereo
HiFi:Speaker-5.1
Where 'HiFi' is the verb name, 'Speaker' is the device name and 'Stereo' is
the variant name.
If we need to define multiple variants, all may be exported like:
HiFi:Speaker-5.1,Mic-4.0
Also, we can enhance this and store the configuration to a file, thus 'HiFi'
can refer to 'HiFi@Speaker-5.1,Mic-4.0' by default.
Verb + list-of-device-variants sounds like a good way to map UCM
devices to pulseaudio profiles (and if there's just one verb, which I
expect to be the common case, don't show it in the profile name). I
don't know how the variants should be configured in UCM, but I know
that device variants should be able to declare conflicts with other
devices (or device variants). For example, 5.1 speaker output may make
recording impossible, while stereo speaker output can be used toghether
with a mic. If this information is not provided by UCM, pulseaudio will
have to probe all variant combinations (like it currently does with the
legacy mixer system).
Sorry, now I realized that the Verb + list-of-device-variants scheme
doesn't really work after all as the profile scheme. Or maybe it does,
but it's significantly different from what we do currently. Switching
between Headphones and Speaker-Stereo often doesn't require reopening
the PCM device, so there's no need for separate Headphones and Speaker-
Stereo profiles. I guess we could still create separate profiles, it
just means that the profile list will get much longer.
We could add a separate optimization step to the profile creation
process. That is, first create all possible device-variant combinations
as the initial profile list, and then inspect which profiles can be
merged. Naming the merged profiles becomes a problem, but I imagine
it's solvable with static rules (e.g. merging Speakers-Stereo and
Headphones becomes Analog-Stereo), and if necessary the merging can be
improved gradually over time.
From profile creation perspective the ideal scheme would be not based
on UCM devices but on PCM devices and their configuration variants, but
I imagine naming would be an even bigger problem with this scheme (how
to map PCM device names to sensible user friendly names?).
I think that I didn't explain my idea in detail. The variant verbs may be
almost identical (thus all devices will be defined) like the "master" one. But
the specific variant configuration will be returned to the application. So it
will differ only in the channel count value for the Speaker device or so. The
PCM device name + PCM parameters check will be fine. I don't think that we
should modify something on the PA side. PA activates only one verb per
soundcard now.
Oh, you want to create variant verbs? Is the idea that all possible
device combinations will be made separate verbs? That would make life
easier for PulseAudio, but wouldn't it mean a lot more work for UCM
configuration writers? Rather than generating the device combinations
automatically in PulseAudio, the combinations would have to be manually
listed in every UCM configuration.
I think it would be better to define only one verb per sound card and
declare the conflicts between the devices or device variants, and let
PulseAudio automatically generate the device combinations as profiles.
I may be misunderstanding something, I didn't for example understand
what you meant by "the PCM device name + PCM parameters check will be
fine". Some examples could be useful. Let's say that there's a sound
card that has stereo output (either headphones or line-out), 4.0
output, 5.1 output, SPDIF output and stereo input. If input is used,
5.1 output can't be used at the same time. Would UCM define the
following verbs?:
HiFi:Headphones,SPDIF,Mic
HiFi:Line-Stereo,SPDIF,Mic
HiFi:Line-4.0,SPDIF,Mic
HiFi:Line-5.1,SPDIF
I'm currently writing UCM configuration for Audigy2, because
PulseAudio's default configuration doesn't work with that card
properly. I'm creating verbs for each possible device combination, and
Note that variants are not supported in UCM yet. I expect to add the
VariantSection to the DeviceSection like this:
SectionDevice."Speaker" {
SectionVariant."4.0" {
Value {
PlaybackChannels 4
... channel mapping (todo) ...
}
}
}
etc.. The alsa-lib will compose the verbs variants. I believe that we should
not duplicate all verb configs just because one line requires a change.
I ran into a naming issue. How should "bidirectional" devices be listed
in the verb name?
If there is a difference between playback/capture parameters or mixer
settings, you cannot define the bidirectional device. But you can use indexes:
SectionDevice."Line1" {
comment "Rear line output"
... configuration for line-out ...
}
SectionDevice."Line2" {
comment "Rear line input"
... configuration for line-in ...
}
plus variants.
If there's both line-out and line-in and SPDIF
supports both input and output, maybe the verb name could be for
example this:
HiFi:Line-4.0-Out,SPDIF-Out,Line-Stereo-In,SPDIF-In
The device name in SectionDevice would be just "Line" or "SPDIF".
I don't really like bidirectional devices, i.e. I'd prefer have
separate SectionDevice names for Line-In and Line-Out, but I guess
merging them into one device can work.
Jaroslav
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
