Latest posts of: Louk

Hi,

I'm building a mixer that should help the user to find a good balance between volume settings of in- and output channels. So I want to couple some VU-meters with mixer faders.

I already did this for Windows XP by selecting the output device and the "Stereo Mix" or "What you hear" input and start a recording using BASS_RecordInit.BASS_RecordSetInput and BASS_RecordStart and finally add a DSP_PeakLevelMeter to it.

Within the limited capabilities of Windows XP, this works fine: I can see the volume levels increasing and decreasing when changing the master volume of the output device with the Windows XP standard mixer.

The next step: Windows 7 and Wasapi...

I finally got this working using the following code:

// deviceId is the device ID of the [b]loop back device[/b], corresponding to the output device to be monitored
   vuMeter.WasapiHandler = new BassWasapiHandler(deviceId, false, 4410, 2, 0, 0);

   if (vuMeter.WasapiHandler.Init())
   {
   if (vuMeter.WasapiHandler.Start())
   {
   int inputChannel = vuMeter.WasapiHandler.InputChannel;
   WriteLog(0, "Wasapi inputChannel = " + inputChannel);
   if (inputChannel >= 0)
   {
   if (!Bass.BASS_RecordSetInput(inputChannel, BASSInput.BASS_INPUT_ON, -1))
   {
   ... Handle exception ...
   }
   }

   if (inputChannel != 0)
   {
   vuMeter.plMeter = new DSP_PeakLevelMeter(inputChannel, 1000);
   vuMeter.plMeter.CalcRMS = true;
   vuMeter.plMeter.Notification += new EventHandler(eventHandler);
   vuMeter.plMeter.Start();
   }
   }
   }

This works, but the problem is that signal shown by the VU-meter is the unprocessed input signal of the device, not the output signal that is controlled by the master fader.

But this is not what I need: I need the VU-meters to follow the real output signal (including the influence of the master volume fader).

What I actually mean is the difference between the gray and green VU-meter lines in the Windows 7 standard mixer.

Any suggestions?