Author: C. Zeitnitz
Last modified: November 2010
Play and Record sound via the soundcard from LabView (™ by National Instruments) utilizing the Windows Sound API.
No license is required for any private or public educational usage. If you plan a commercial application with WaveIO, please obtain a license here.
Most modern soundcards support not only standard sampling rates of up to 44.1kHz, but will work up to 100kSamples at 16Bit resolution. This is even true for low cost soundcards. The provided windows DLL and the interface VIs allow to select all possible combinations of channel numbers, sampling rates and resolutions. The number of used buffers is user selectable for input and output of data. The buffer size can be defined in terms of time (msec) or samples per buffer and channel.
LabView example VIs to play multiple channels as well as the recording of sound data are provided in the package.
The above example opens a sound device to record data. After starting the device the data are read in a loop and displayed in a graph until either the stop button is pressed, or an error occurs. When the sound device is no longer needed by the application it has to be stopped and closed.
A user selectable timeout should avoid any hangup within the DLL code. The DLL makes only Windows system calls and does not use any LabView libraries.
Currently the code supports only PCM data. No other sound codecs are supported at this time!
This program has been tested under Windows 2000/XP/Vista/7 with LabView 7.1 or above. Be aware, that the load on the machine can be substantial, if multiple channels are used with high sampling rates. For an output of 6 channels to a 5.1 soundcard with 100kHz the transfer rate of the data is already 1.2MBytes per second (16Bit resolution) ! So, choose the parameters acording to the ability of your system and monitor the load !
This Software and all previous versions are NO Freeware!
The use of the software and of the documentation is granted free of charge for private and non-commercial use in educational institutions. Any commercial application, distribution and sale is prohibited.
A licensed version of the Software is available here. This allows any commercial usage, except distributing the Software standalone.
All right reserved.
I can not solve your sound card related problem. So, please only send mail, if you have a real problem related to WaveIO!
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