Windows Mobile/CE Audio Input Gain Control RRS feed

  • Question

  • Hi all,

    I am a software engineer at Lucas Systems Inc., which their projects and products utilize voice recognition technology.

    The company uses the Windows CE/Mobile based devices for their development and so far have been using the OEM proveded APIs for changing audio input gain. We would like to have our software run on the off-the-shelf devices running Windows Mobile as well, however,  we have not been able to find APIs or any resources that would help us to be able to set the input gain levels within our software such devices.
    I came across http://msdn.microsoft.com/en-us/library/bb415624.aspx page which describes best practies for voice recognition, suggesting the following:

    "Automatic Gain Control (AGC) generally distorts the audio due to gain pumping, and drops recognition accuracy rates by as much as 20%. If AGC is provided, it is strongly recommended that it be turned off by default, with an option to turn it on."

    That leads me to believe that there is a way to toggle AGC on or off, and to be able to set the input gain levels specific to the conditions where the our voice application is in operation.

    What I am looking for is a way to toggle AGC on or off, and be able to set input gain levels programmaticly via some set of MS provided APIs, which would work on Windows CE based devices.

    Thanks any help you can provide.

    Arash Bannazadeh

    Thursday, July 2, 2009 3:26 PM