Re: Driver Samples
From: Dean Ramsier (ramsiernospam_at_nospam.com)
Date: 09/29/04
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Date: Wed, 29 Sep 2004 11:24:39 -0400
OK, then I've got a question. What exactly is meant by the UAM "model" and
the "UAM interfaces"? If I was to write my own audio driver based on this
model, how would I go about doing it? It looks to me like everything boils
down to implementing the defined waveform audio IOCTLs, mixer IOCTLs, and
(no longer as of CE5) DSound IOCTLs. I was under the impression that
writing a UAM version basically meant implementing all of it on your own,
replacing the functionality that would normally be provided in the MDD. I
didn't see much high level code that looked reusable (although I didn't
spend a lot of time looking). How is this different from just modifying the
MDD to support multiple streams?
Maybe we're all missing the value of a UAM driver, since there isn't any
documentation on what makes it a model versus a fully custom driver intended
for one particular sound card. If I've got to write a full custom driver,
it's a lot easier to start with something and the MDD is as good a place as
any...
Thoughts?
-- Dean Ramsier - eMVP "Bill Rainford [MS]" <brain@microsoft.com> wrote in message news:eb5j$XcpEHA.592@TK2MSFTNGP11.phx.gbl... > The UAM model is still supported in CE 5.0. DSound is no longer supported, > but this does not negate the value of the UAM driver. The UAM driver better > supports mixing as well as offering the benefits pasted below from the docs. > > See the Enoniq UAM sample driver for the driver specifics. > The sample code for Wavedev drivers is located in > %_WINCEROOT%\Public\Common\Oak\Drivers\WAVEDEV. > > The info below is Pasted from: > ms-help://MS.WindowsCE.500/wceddk5/html/wce50conunifiedaudiomodel.htm > The UAM supports the standard wave driver interfaces. The previous wave > driver internals and sample drivers consisted of the model device driver > (MDD) and platform-dependent driver (PDD) modules. The MDD module implements > the hardware-independent part of the driver and exports the driver > interfaces to the middleware. The PDD module provides the hardware-dependent > implementation of the driver. > > Using MDD and PDD, the previous model had the following limitations: > > a.. No support for multiple streams > b.. No multiple devices on one driver > c.. No reliable support for looping > d.. Poor support for streaming > OEMs can work around these limitations by modifying the MDD or writing their > own complete driver that exports the proper interfaces to the middleware. > > With the UAM model, MDD and PDD are not necessary to writer a driver. You > will be able to take advantage of the UAM interfaces. > > The UAM provides the following advantages: > > a.. Robustness: Lessens the number of mixing-related problems you will > encounter. > b.. Clarity: Eliminates confusion over which audio driver to write. > The following illustration shows the UAM stack. > > > -- > Bill Rainford [MS] > --- > This posting is provided "AS IS" with no warranties, and confers no rights. > > > > > "Steve Maillet (eMVP)" <nospam1@EntelechyConsulting.com> wrote in message > news:%23yVUfPwoEHA.648@tk2msftngp13.phx.gbl... > > Somebody forgot to tell the documentation team that there was no longer a > > need to have the Unified Audio Model docs because there is no direct sound > > anymore. DirectSound is not supported in the OS anymore therefore there is > > no need for a Unified Audio Model Driver. You can write one but the OS > will > > never call ANY of the DirectSound related portions so it would be a waste > of > > time. > > > > -- > > Steve Maillet > > EmbeddedFusion > > www.EmbeddedFusion.com > > > > Do have an opinion on the effectiveness of Microsoft Windows Mobile and > > Embedded newsgroups? Let us know! > > https://www.windowsembeddedeval.com/community/newsgroups > > > > > >
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