[pulseaudio-discuss] [RFC PATCH 0/3] alsa: Support for only-multichannel devices

[Raymond Yau]

>>
>>  >
>>  > This should allow us to automatically probe devices using the recent
>>  > firewire drivers, as well as some USB devices people have been asking
>>  > about lately.
>>  >
>>  > Sorry that it has taken some time since I said I would work on this
patch
>>  > set, and I've rewritten and rethought it as well a few times. Anyway,
>> here's
>>  > a proposal.
>>  >
>>  >  * Exact-channels can be set to false to allow devices to be opened
with
>>  >    any channel count instead of just the one specified in the channel
>> map.
>>
>> Do these kind of devices need more than one profile if they have same
>> channel Min and channel Max and both are larger than two ?
>
>
> This seems to be the common case that we're trying to handle here, and it
will end up with the profiles "off", "generic input" "generic output" and
"generic output + generic input".
>
>
>> How can user capture stereo from a FireWire device which only support 6
>> channels
>
>
> With this patch set, PA will setup a default channel map. I e, recording
stereo will mean recording from the first two channels.
>

If you can provide a virtual stereo playback/capture on a multichannel
devices which does not support stereo

Does this mean that virtual surround40, surround51 will also be supported ?

>
>> capture as pulseaudio downmix 6 channels to stereo for playback
>> stream?
>>
>> Can pulseaudio provide a control to select  stereo capture from first
>> Jack, second jack .... ?
>
>
> You'll need module-remap-source for that.
>
>
>> The problems are non standard volume control names
>
>
> The firewire drivers currently don't implement volume controls the normal
ALSA mixer way.
> For some other cards (PCI, USB), you're right that the names are
sometimes non standard. Please fix that in ALSA. :-)
>

Do you really need to probe all other profiles when your first probe
already know both channels_min and channels_min are same and larger than
two ?
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