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Echo Sample Overview

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[The feature associated with this page, Windows Media Player SDK, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of Windows Media Player SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

This guide builds a Windows Media Player DSP plug-in that creates an echo effect in PCM audio during playback. The goals for the plug-in are as follows:

  • The plug-in processes 8-bit or 16-bit PCM audio only.
  • It supports a delay time between 10 milliseconds (ms) and 2000 ms (2 seconds). This represents a practical range for most applications.
  • It supports mixing of the original signal with the delay signal.
  • It provides a property page implementation that allows the user to provide a value for the delay time and a value for the percentage of delay signal relative to the overall audio signal level.
  • The code is created by modifying the Windows Media Player Plug-in Wizard audio DSP plug-in sample.

The Echo sample is not included with the Windows Media Player SDK; it is a sample that you create. To create the Echo sample, you must start with the default project from the Windows Media Player Plug-in Wizard. You can name the project whatever you like; this documentation assumes the project is named Echo. For details about using the wizard, see Building a DSP Plug-in.

The following section provides an overview of how the sample creates an echo effect:

The Echo Sample