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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>

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.

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©2001-2007 Gary P. Scavone, McGill University. All Rights Reserved. Maintained by Gary P. Scavone.