Basic app that displays a melspectrogram generated from an audio file

[janezdu]

• Switch main architecture of project to WinUI 3, instead of WPF.
  • Main Solution Found in Samples/AudioPreprocessing/WinUI/AudioPreprocessing/
• Uses appropriate FileOpenPicker (not System.Windows.Forms) to choose .wav file
• displays one MelSpectrogram in the center of the app.

Currently, the button SaveFile and the textbox below it (that displays the path to which the image is saved) do not work with these changes.

[tiagoshibata]

A cast throws an exception if it fails:

var initializeWithWindowWrapper = (IInitializeWithWindow)Marshal.GetTypedObjectForIUnknown(picker_unknown, typeof(IInitializeWithWindow));

It's probably better than doing as and then asserting (and it seems from GetTypedObjectForIUnknown docs that it always returns a IInitializeWithWindow or throws an exception, so the assertion seems to always succeed?)

[janezdu]

That makes sense to me.