Re: Multiple Sound Devices
Re: Multiple Sound Devices
- Subject: Re: Multiple Sound Devices
- From: Jeff Moore <email@hidden>
- Date: Tue, 12 Feb 2002 12:14:23 -0800
on 2/12/02 2:58 AM, Mark Thomas <email@hidden> wrote:
>
Hmmmm, any idea of where some docs on 'sdev', as I guess I can count the
>
number of 'sdev', and ask them for some information, I guess there are docs
>
for 'sdev' somewhere, but I'll never be able to switch to particular
>
speaker, because of this.
>
>
Also what are these SoundComponent APIs in <Sound.H>, are these output
>
components info functions, as I cannot find any docs on them or sample code,
>
is there any available I can have. ???
>
>
Also what are SPBxxxxx funcations used for ???.
Well, the first place you need to go is here:
<
http://developer.apple.com/techpubs/quicktime/qtdevdocs/RM/sndframe.htm#sou
nd>
Everything you need to know about the Sound Manager is here.
As others have said, on X the Sound Manager sits on top of CoreAudio using
an sdev that talks to the HAL. There is only one sdev, no matter how many
device's are attached to the system. This sdev talks to the HAL's default
device.
The Sound Manager doesn't have any built-in sense of what devices are
attached to the system. It uses sdev components and the Component Manager to
provide this knowledge. Because of this lack of any meaningful abstraction,
it isn't possible to have an sdev for every device on the system, so the
single sdev suffices for most of what the Sound Manager is used for.
>
When you are in the Sound Control Panel, it seems to known about the
>
different output devices. Any Ideas how it does this ???.
The reason why is that on 9, sdev components are the driver model. Using
FindNextComponent, you can iterate across all the known devices on the
system.
On X, the Sound Prefs Panel uses CoreAudio to do it's work, so it has full
access to all the devices as well.
--
Jeff Moore
Core Audio
Apple
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.