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# Recording

Using RtAudio for audio input is almost identical to the way it is used for playback. Here's the blocking playback example rewritten for recording:

    #include "RtAudio.h"
    #include <iostream>
    #include <cstdlib>
    #include <cstring>

    int record( void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames,
             double streamTime, RtAudioStreamStatus status, void *userData )
    {
      if ( status )
        std::cout << "Stream overflow detected!" << std::endl;

      // Do something with the data in the "inputBuffer" buffer.

      return 0;
    }

    int main()
    {
      RtAudio adc;
      if ( adc.getDeviceCount() < 1 ) {
        std::cout << "\nNo audio devices found!\n";
        exit( 0 );
      }

      RtAudio::StreamParameters parameters;
      parameters.deviceId = adc.getDefaultInputDevice();
      parameters.nChannels = 2;
      parameters.firstChannel = 0;
      unsigned int sampleRate = 44100;
      unsigned int bufferFrames = 256; // 256 sample frames

      try {
        adc.openStream( NULL, &parameters, RTAUDIO_SINT16,
                        sampleRate, &bufferFrames, &record );
        adc.startStream();
      }
      catch ( RtError& e ) {
        e.printMessage();
        exit( 0 );
      }

      char input;
      std::cout << "\nRecording ... press <enter> to quit.\n";
      std::cin.get( input );

      try {
        // Stop the stream
        adc.stopStream();
      }
      catch (RtError& e) {
        e.printMessage();
      }

      if ( adc.isStreamOpen() ) adc.closeStream();

      return 0;
    }

In this example, we pass the address of the stream parameter structure as the second argument of the RtAudio::openStream() function and pass a NULL value for the output stream parameters. In this example, the record() callback function performs no specific operations.

| ©2001-2012 Gary P. Scavone, McGill University. All Rights Reserved. Maintained by Gary P. Scavone.