[pulseaudio-discuss] [RFC] Alsa UCM integration.

[Tanu Kaskinen]

On Fri, 2011-02-25 at 14:09 -0600, Margarita Olaya wrote:
> > Make sense.
> > But I am not sure the profiles as defined today in PulseAudio can work
> > with modifiers. What we discussed yesterday is that when a profile is
> > selected then you would set the UCM verb and know about all possible
> > sinks. We would need additional logic to have profile modifiers, or we
> > would need extra profiles to represent all possible combinations
> > (speech, speech+tone, speech+music, etc).
> 
> The initial idea is to use the UCM data to generate the card profiles,
> then when the stream is open PA will use his method to select the
> profile and set the verb. e.g when UCM is present: profile = verb.
> 
> In the UCM module the data is store in a proplist per verb, the
> proplist has the following info:
>         PA_PROP_UCM_SINK ->      "PlaybackPCM"
>         PA_PROP_UCM_SOURCE ->         "CapturePCM"
>         PA_PROP_UCM_PLAYBACK_VOLUME ->  "PlaybackVolume"
>         PA_PROP_UCM_PLAYBACK_SWITCH -> "PlaybackSwitch"
>         PA_PROP_UCM_CAPTURE_VOLUME ->  "CaptureVolume"
>         PA_PROP_UCM_CAPTURE_SWITCH -> "CaptureSwitch"
>         PA_PROP_UCM_QOS -> "TQ"

This means that there's only one sink and source per verb. That's
probably ok, but if profile = verb, then this also means that there's
only one sink and source per profile. That makes it impossible to have
two verbs (or is it verb+modifier in UCM speak?) active at the same time
on one card.

I don't know what would be the right solution to this problem. I don't
know enough about UCM concepts even to try to propose any solution. Is
there any documentation?

> plus the list of devices e.g headphone, headset and modifiers e.g
> "play tone", "play music", etc.

I thought verbs were the concept for abstract devices, but apparently I
was wrong. Are verbs then stream types? If they are, I think Pulseaudio
shouldn't create profiles based on verbs. The profiles should be created
based on the devices. You mention headphone and headset as examples of
devices - do they also have the same set of properties defined by UCM,
that is, playback PCM, capture PCM, and mixer element names for volume
and mute?

-- 
Tanu