Change Line in volume of recording control

[test_man]

Hi,

I downloaded this volume control library from NI wed site but it does not allow me to conrol Line in volume of recording property.

Can any one help me out please?

[Jarrod_S.]

Hi Sheetal,

You can change this easily from the Block Diagram. On the Block Diagram you'll see a Stacked Sequence structure with 2 cases, one to change the wave volume and one for the speaker volume. These cases access separate dwComponent Type enum constants. You can either select Line In from one of these enums or add a third case identical to the first two, except with Line In selected for the dwComponent Type as shown below:

Message Edited by Jarrod S. on 03-08-2006 12:11 PM

[test_man]

Thanks for your reply.

As I mentioned in my question I want to change Line In property of Recording Control NOT Line In property of Volume Control.

Please take a look at attached screen shot.

[Jarrod_S.]

Ah, I see the distinction. Sorry about that. This example was calling Windows Media functions from winmm.dll. If you want to modify it, I'd suggest looking up information at www.msdn.com, the Microsoft Developer Network. I found the following information there by searching for MixerGetLineInfo, one of the DLL calls made that uses this dwComponent Type input. This page also links this page with more information on the dwComponent Type constants that can be accepted.

This document doesn't explicitly list the hex values for these inputs, but you can find some examples from this example VB program that modifies some of these lines. This should help you get started.

There are a number of other constants in these documents that aren't used in the enum in the LabVIEW example, though the constants that are listed have cryptic names at best sometimes. Hopefully you'll have more luck finding the right hex constant to input here. They seem to be split up into Source and Destination constants, depending on whether you're inputting data from an ADC or outputting to speakers or headphones, etc.