[wdmaudiodev] AW: Re: Starting to dev. a virtual Midi Port [bcc][faked-from]
- From: Tobias Erichsen <erichsen@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Mon, 16 Jul 2012 08:33:34 +0000
Hi there,
I just saw this post and and since I'm the author of the mentioned virtual
MIDI-driver,
I looked into my mail-account and could not find your mail, could you tell me
with which
email-address you sent this mail and on what date?
Best regards,
Tobias
Von: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx]
Im Auftrag von Revan Foly
Gesendet: Samstag, 14. Juli 2012 00:51
An: wdmaudiodev@xxxxxxxxxxxxx
Betreff: [wdmaudiodev] Re: Starting to dev. a virtual Midi Port
[bcc][faked-from]
Hi,
So I see I have different approaches available. Even though my program doesn't
transmit any sound just NoteOn/Off and CC data, latency is a very important
issue, therefore I'd like to try the most performant method, i it is reasonable
for me to try getting it to work. If I'm correct that would be the Kernel
Streaming method which is also the newer method and can also be expected to
work with windows 8?
On the other hand, if you Google "virtual MIDI driver", you'll find that there
are lot of people who have ready-made solutions.
The only one that seemed to be exactly what i needed and also free was
virtualMIDI, however the author didn't respond on a request mail I sent him
earlier.
Are you saying you just ran mpu401.sys at a command line?
Well I admit it was kinda foolish but from what I read in the WDK
Documentation, all that was necessary to test the driver was to configure a
remote computer and then select the correct debugger in visual Studio 2012 RC
and press "start debugging" - so I thought just selecting local debugging mode
would be a thing worth trying. Maybe VS2012 would handle everything by itself.
Every WDK sample includes one, and there is certainly documentation for them.
Well I think you said it before but I definitely can't find a prepared INF file
in this sample:
http://code.msdn.microsoft.com/Audio-Adapters-Samples-a61b6d06/view/SourceCode#content
I'm not sure from what viewpoint you are asking this. In a kernel driver, the
Kernel Streaming system creates the user-accessible device objects for you,
when you initialize Kernel Streaming. In portcls drivers (like MPU401 and
FMSynth), the Port Class driver does that for you, using the information you
return to it.
So if in both cases the port that other programs can connect to via midiIn and
midiOut are created by the "allready there part" of the driver, what exactly do
I have to submit to the driver. just the link between my application and the
driver?
Thank you very much for your help already, its greatly appreciated and I think
if I hadn't got an answer on my first mail, I would have given up already ;)
________________________________
Date: Fri, 13 Jul 2012 14:49:50 -0700
From: timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] Re: Starting to dev. a virtual Midi Port
Revan Foly wrote:
right, so i used the time to read into the WDK a bit more and it actually
confused me more than get me anywhere. It looks like I need a Kernel Driver to
access Kernel Streaming.
Well, more accurately, you need a kernel driver if you plan to provide Kernel
Streaming services. However, that's not the only way to provide MIDI data. It
is still possible to create a user-mode driver using the WINMM "installable
driver" model. In that case, you write a user-mode DLL that handles the midiIn
and midiOut functions almost directly. There's a thread here that talks a
little more about this:
http://www.osronline.com/showthread.cfm?link=185751
The problem is, the last DDK that contained a sample was NT 4, but that simple
still builds and works.
On the other hand, if you Google "virtual MIDI driver", you'll find that there
are lot of people who have ready-made solutions.
How are you starting and debugging it?
I selected the local debugger and simply started debugging. I didn't see the
point in configuring a testing machine.
Are you saying you just ran mpu401.sys at a command line? You didn't copy it
to \Windows\System32\Drivers and create a service entry for it? Drivers have
to be configured, and then started by the operating system. You don't get to
run them yourself.
kernel drivers, so they have to be installed with an INF file
Again WDK wasn't much help in finding out how to write one / generate one.
Every WDK sample includes one, and there is certainly documentation for them.
Now, I will freely admit that INF writing is a bit of a dark art, especially
for audio drivers, but the samples are there.
My biggest problem atm is that I probably simply don't see in the samples where
the MIDI Port is created and how data is passed to it. Any suggestions on where
to start?
I'm not sure from what viewpoint you are asking this. In a kernel driver, the
Kernel Streaming system creates the user-accessible device objects for you,
when you initialize Kernel Streaming. In portcls drivers (like MPU401 and
FMSynth), the Port Class driver does that for you, using the information you
return to it.
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
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