locked
Sound card interfacing RRS feed

  • Question

  • I am researching a way to sample audio input to the sound card.  What I want to do is monitor the audio output of a weather radio and decode the NWR SAME data stream (when present) to write to a file.  The data itself is transmitted over normal AFSK audio (2083.3 Hz Mark, 1562.5 Hz Space) at 520.83 bits per second.  The data is streamed as 8-bit, No Parity and One stop bit.

    I'm looking for a starting point as far as coding this using C#, specifically some examples of sampling input audio, and what tools in the .NET library are best to use for this.

    Thanks for any input / help.

    Todd

     

    • Moved by Larcolais Gong Thursday, May 26, 2011 3:43 AM (From:Visual C# General)
    Wednesday, May 25, 2011 3:33 PM

Answers

  • tcanaday wrote:
    >
    >I am researching a way to sample audio input to the sound card.
     
    There are several ways.  The waveIn APIs are the easiest to use, although a
    DirectShow graph might be more flexible.  There are also some third-party
    libraries for doing audio in C#.
     
    >What I want to do is monitor the audio output of a weather radio and
    >decode the NWR SAME data stream (when present) to write to a file.
    >The data itself is transmitted over normal AFSK audio (2083.3 Hz
    >Mark, 1562.5 Hz Space) at 520.83 bits per second.  The data is
    >streamed as 8-bit, No Parity and One stop bit.
     
    You're going to want to look for a library for decoding that.  I, for one,
    would not do a compute-intensive task like that in C#.
    --
    Tim Roberts, timr@probo.com
    Providenza & Boekelheide, Inc.
     

    Tim Roberts, DDK MVP Providenza & Boekelheide, Inc.
    Friday, May 27, 2011 6:13 AM

All replies

  • I help you moving your thread into WDK forum. You will get more helpful suggestions from there.

    Best Regards,


    Larcolais Gong[MSFT]
    MSDN Community Support | Feedback to us
    Get or Request Code Sample from Microsoft
    Please remember to mark the replies as answers if they help and unmark them if they provide no help.

    Thursday, May 26, 2011 3:42 AM
  • Well again, just because a poster mentions something IO related does not make the topic appropriate to the WDK forum.

    I believe the OP is asking a win32 (via C# and .Net) programing question. 

    Perhaps this would be a good starting point: http://msdn.microsoft.com/en-us/library/dd370784(v=vs.85).aspx

     

    That is the SDK link. A little research would probably reveal if this is exposed in .net, otherwise it is pInvoke and the usual marshalling drudgery.

     


    Mark Roddy Windows Driver and OS consultant www.hollistech.com
    Thursday, May 26, 2011 8:00 PM
  • tcanaday wrote:
    >
    >I am researching a way to sample audio input to the sound card.
     
    There are several ways.  The waveIn APIs are the easiest to use, although a
    DirectShow graph might be more flexible.  There are also some third-party
    libraries for doing audio in C#.
     
    >What I want to do is monitor the audio output of a weather radio and
    >decode the NWR SAME data stream (when present) to write to a file.
    >The data itself is transmitted over normal AFSK audio (2083.3 Hz
    >Mark, 1562.5 Hz Space) at 520.83 bits per second.  The data is
    >streamed as 8-bit, No Parity and One stop bit.
     
    You're going to want to look for a library for decoding that.  I, for one,
    would not do a compute-intensive task like that in C#.
    --
    Tim Roberts, timr@probo.com
    Providenza & Boekelheide, Inc.
     

    Tim Roberts, DDK MVP Providenza & Boekelheide, Inc.
    Friday, May 27, 2011 6:13 AM