Re: [OT] ALSA userspace API complexity

Hannu Savolainen
2006-01-06T03:33:43Z

On Fri, 6 Jan 2006, Edgar Toernig wrote:

> Hannu Savolainen wrote:
> >
> > Takashi Iwai wrote:
> > >
> > > - Split of channels to concurrent accesses
> >
> > Could you be more specific with the above isues?
>
> As I understand it: instead of providing one device with 5.1 capabilities
> provide one device with 3 concurrent stereo users. Reading the datasheet
> of my AC'97 decoder (a cheap ALC650 connected to an ATIIXP) there is hard-
> ware that supports this[1].
Then this is in no way an API issue. Many OSS drivers (including envy24)
create separete device files for each input/output channel (or device pair).
Applications can chose to open the first device file in for all the
channels or any combination of the devices in mono/stereo/n-channel mode.

All this depends only on the driver implementation. There is nothing API
related. Any app can open the devices as usual without paying any
attention on the channel allocation (which is done automatically by the
driver). xmms (or whatever else consumer app) can open the device and ask
for stereo access. Equally well a DAB application can open the device and
ask for full 10 output channels (or anything between 1 and 10). No special
API features are needed for this.

Best regards,

Hannu
-----
Hannu Savolainen (hannu@opensound.com)
http://www.opensound.com (Open Sound System (OSS))
http://www.compusonic.fi (Finnish OSS pages)
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