[wdmaudiodev] Re: Audio control for recording not possible???
- From: "Jerry J. Trantow" <Jerry.Trantow@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Tue, 24 Sep 2002 09:11:23 -0500
My understanding of your problem is that the Windows multimedia control
panel doesn't have a control for sending record volume information to
your device. Your device firmware implements the audio control, but
there isn't a built in way to get information to it.
Filter drivers are a method of adding functionality to the existing
drivers. My suggestion is to write and install a filter driver
(probably on top of usbaudio.sys) that would translate IOCTLs from
DeviceIOControl into the appropriate usb messages for the audio control.
You would also need to write a simple control panel that would call
DeviceIOControl to send the messages.
The control panel is very simple code. You need to monitor the
PlugNPlay of appropriate devices and send a few IOCTL messages.
Ideally, you write this as an automation server so people can use VB or
Java scripts to control it.
The filter driver simply translates the IOCTLs into the appropriate usb
commands for your device. The DDK has a bunch of UsbBuild macros which
make it easy to put the usb command together.
My experience has been that the biggest problem is supporting all the
peculiarities between different OS especially when it comes to
installing drivers.
I have done several contract jobs similar to this. If you are
interested in contracting out this work we should take this discussion
out of wdmaudiodev. jtrantow@xxxxxxxxxxxxxxxxxxxxxxxxxxx
-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Ajai James
Sent: Monday, September 23, 2002 7:34 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Audio control for recording not possible???
Hi Jerry,
Thanks a lot for your suggestion and help. Can you explain a little bit
more? So do I need to use a custom made application(like control pannel)
to change the volume of the recorded file? This control communicates
directly with the filter driver which in turn communicates with the USB
audio control firmware which should change the DAC out put
amplification, is it that way?
Also, is there any way posible to be in the firmware framework alone,
and change the volume, without modifying or adding the host driver
part?
Thanks to you a lot again..
Ajai
ajaijames@xxxxxxxxx
"Jerry J. Trantow" wrote:
You can always write and install a filter driver which communicates to
the audio control. Then use DeviceIOControl from some type of control
panel to send messages to the driver which converts it to the
appropriate USB command.
-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Ajai James
Sent: Monday, September 23, 2002 1:54 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Audio control for recording not possible???
Hi friends,
I am using an Ez USB board to prepare a demo audio project.I have a
requirement to increase the volume of my recorded wav file depending on
the buttons on my kit, ie vol up and down. The enumeration is ok now,
and the firmware keeps on pumping the hard coded sine tone values to
the host.So, after selecting th enumerated board as a recording device,
I can record the sine tone. Now, i want to change the volume of the sine
tone using my boards f1, f2 push buttons. I thought I could use the
control end point with Vol up, vol down for that. But it does not seem
to work.
On going through microsoft documentation
,http://www.microsoft.com/hwdev/tech/input/audctrl.asp
it seems that audio controls are supported for play back only, not
recording..
Am i correct in this assumption? any way to implement this without using
the audio controls
Thanks a lot, for your kind suggestions and comments ...
Ajai James
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