IronTunes Tutorial

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Microsoft Windows SDK for Windows 7 and .NET Framework 3.5 SP1 can be used in place of the Visual Studio 2008 installation.

Introduction

IronTunes is a music player built upon the IronPython framework and utilizes several Windows libraries to play music files. For example, COM Interop is used to connect to the DirectShow API which in turn plays the actual files. This simply means that we do not have to implement the code to convert audio files to actual sounds ourselves. Additionally, IronTunes uses a Windows Presentation Foundation based graphical user interface. One of the major benefits of using WPF from IronPython is that it makes writing GUIs very easy.

IronTunes comes with two separate GUIs to showcase that you can design UI independently from the code. To see this, save a copy of CurrentSkin.xaml, and copy NewSkin.xaml over CurrentSkin.xaml. Then re-launch IronTunes. NewSkin.xaml adds a seek slider and images for the buttons. Use the thinner plus-sign button to add an individual file and the thicker plus-sign button to add an entire directory.

Using IronTunes

To start IronTunes, run "ipy.exe IronTunes.py" from the IronTunes directory. Add files by clicking the "Add File" or "Add Dir" buttons. The files you add will show up in the library view below. You can select a file and click "Play/Pause" to start playing it.
Typing in the search box in the top right will filter the library as you type.
The other features work pretty much as expected: Back, Forward, and Volume Control. Information about the currently playing track is displayed at the top in the center.

COM Interop and General Explanation of How IronTunes Functions

IronTunes uses quartz.dll (in the system32 directory) by generating an interop assembly with the tlbimp.exe tool. See the IronPython tutorial for more info. The Player object (player.py) constructs a FilegraphManagerClass object from quartz.dll via the interop assembly QuartzTypeLib.dll. Player calls into the FilegraphManagerClass object to play the audio files. The Player object calls the RenderFile method with a filename to setup the filter graph to render the file. Then it can call the Run (to play), Stop, and Pause methods. The Player object also registers the program's main window with the filter graph manager to send notification messages. In order to handle these there is an extra wndproc hooked into the main window which sends notifications to the player object when it needs to respond to filter graph events (it calls the ProcessEvents method). This allows the program to advance to the next item on the playlist when an item finishes playing.

Generating the COM Interop Assembly

For this example to run, it is required that you create the quartz (i.e., DirectShow) interop assembly on your own by following these simple steps:

        C:\IronPython\Samples\IronTunes>tlbimp %SystemRoot%\System32\quartz.dll
        Microsoft (R) .NET Framework Type Library to Assembly Converter 2.0.50727.42
        Copyright (C) Microsoft Corporation. All rights reserved.

        Type library imported to QuartzTypeLib.dll

Windows Presentation Foundation

IronTunes builds a new WPF window and loads the XAML file CurrentSkin.xaml. It then sets the window's DataContext to be the application's dataModel, so that the bindings in the XAML file can allow the user interface to reflect the program's state. It also creates an IronTunesWindow object (IronTunesWindow.py) and uses its enliven method to attach event handlers to the buttons.

Library Management

The Library class (library.py) manages the current music library. It implements the functionality of adding files and directories (recursively) to the current library, and allows the current library view to be filtered and sorted (by a SearchFilter object implemented in SearchFilter.py).