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Audio Drivers (Compact 7)

  • Article

3/12/2014

Learn about Windows Embedded Compact 7 audio drivers. This topic includes links to reference information and samples.

Audio drivers enable audio support on Windows Embedded Compact 7 devices that are capable of playing sound. Use the waveform audio API to communicate with audio drivers for your device to play sounds, music, or other audio effects in your application.

Communication between the audio drivers and your application is handled by the Audio Device Manager, which manages the available audio devices and handles various aspects of security, interprocess communication, and application callbacks. The Audio Device Manager includes a kernel-mode software-based mixer.

The audio driver architecture for Windows Embedded Compact supports driver creation using the unified audio model (UAM), the model device driver (MDD), and the platform device driver (PDD) model. The architecture also supports various types of audio compression manager (ACM) drivers such as codecs, converters, and filters.

To add this feature to your OS, see Audio Driver Catalog Items.

For reference information, see Audio Driver Reference.

The following ACM driver samples are provided in %_WINCEROOT%\Public\Common\OAK\drivers\ACM:

  • The MSFILTER sample provides a simple volume and echo filter. (Both filters are supported within the same driver). This driver supports a custom icon and a custom About dialog box. The ACM provides a default icon and About dialog box for drivers which do not provide their own. Microsoft recommends using the default About dialog box because the driver code is simpler and smaller.
  • The GSM610 sample implements the GSM 6.10 voice encoding standard originally developed for digital cellular telephone encoding. It supports a configuration dialog box and automatic configuration code.

The following wavedev driver sample is provided in %_WINCEROOT%\Public\Common\Oak\Drivers\WAVEDEV:

  • The sample audio driver MDD layer implements a single audio device capable of playing and recording pulse code modulation (PCM) waveform audio. The sample code supports simultaneous recording and playing but can also be used with audio devices that can perform only one function at a time. The PDD layer communicates with the audio hardware to start and stop playing and recording and to initialize and deinitialize the hardware.

Source code for this feature is available at %_WINCEROOT%\Public\Common\OAK\Drivers\ACM and %_WINCEROOT%\Public\Common\OAK\Drivers\WAVEDEV.

For information about Windows Embedded Compact Test Kit (CTK) tests that apply to this type of driver, see Audio LoopBack Test.

See Also

Other Resources

Device Drivers
ACM Wrapper Filter
Audio Capture Filter
Audio Renderer (WaveOut) Filter
Waveform Audio
Windows Media Player