Audio recording using C++

03 Oct 2023

In this post, we will explore how to record audio using the C++ programming language. Audio recording can be useful in various applications, such as voice recognition systems, multimedia applications, and audio processing.

Required Libraries

To capture audio in C++, we will use the portaudio library, which provides a platform-independent interface for audio input and output. The portaudio library can be easily installed using package managers like Homebrew on macOS or apt-get on Linux.

Setting Up PortAudio

Before we start, make sure portaudio is installed on your system. You can verify this by running the following command in your terminal:

$ portaudio --version

If portaudio is not installed, you can install it by following the instructions provided on the library’s official website.

Recording Audio

To record audio, we need to initialize and configure the portaudio library in our C++ code. Here’s an example of how to record audio for a specific duration:

#include <iostream>
#include <portaudio.h>

// Constants
const double SAMPLE_RATE = 44100.0;
const int NUM_CHANNELS = 1;
const int FRAMES_PER_BUFFER = 512;
const int DURATION_SECONDS = 5;

// Callback function
int recordCallback(const void* inputBuffer, void* outputBuffer,
                   unsigned long framesPerBuffer, const PaStreamCallbackTimeInfo* timeInfo,
                   PaStreamCallbackFlags statusFlags, void* userData)
{
    // Access the recorded audio data
    const float* audioData = static_cast<const float*>(inputBuffer);

    // Process or save the audio data as needed
    // ...

    return paContinue;
}

int main()
{
    Pa_Initialize();

    // Set up stream parameters
    PaStreamParameters inputParameters;
    inputParameters.device = Pa_GetDefaultInputDevice();
    inputParameters.channelCount = NUM_CHANNELS;
    inputParameters.sampleFormat = paFloat32;
    inputParameters.suggestedLatency = Pa_GetDeviceInfo(inputParameters.device)->defaultLowInputLatency;
    inputParameters.hostApiSpecificStreamInfo = NULL;

    // Open the audio stream for recording
    PaStream* stream;
    Pa_OpenStream(&stream, &inputParameters, NULL, SAMPLE_RATE, FRAMES_PER_BUFFER, paClipOff, recordCallback, NULL);

    // Start recording
    Pa_StartStream(stream);

    // Wait for the specified duration
    Pa_Sleep(DURATION_SECONDS * 1000);

    // Stop recording
    Pa_StopStream(stream);

    // Clean up
    Pa_CloseStream(stream);
    Pa_Terminate();

    return 0;
}

Conclusion

With the help of the portaudio library, we can easily record audio in C++. This enables us to implement various audio-related functionalities in our applications. Remember to handle errors and add additional audio processing logic as needed.

#audio #c++