Qt--使用RtAudio进行录音以及播放

忘是亡心i 2022-09-26 11:52 345阅读 0赞

其实，本篇博客主要是介绍一下RtAudio，只是在qt中使用罢了！

**什么是RtAudio？**  
RtAudio provides a common API for realtime audio input/output across Linux (native ALSA, Jack, and OSS), Macintosh OS X (CoreAudio and Jack), and Windows(DirectSound, ASIO and WASAPI) operating systems.

**官方地址：**  
[http://www.music.mcgill.ca/~gary/rtaudio/][http_www.music.mcgill.ca_gary_rtaudio]

**github地址：**  
[https://github.com/thestk/rtaudio][https_github.com_thestk_rtaudio]

**下载rtaudio：**  
最新版本 (22 February 2016): Version 4.1.2

**官方文档应用例子：**

#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 ( RtAudioError& 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 (RtAudioError& e) {
        e.printMessage();
      }
      if ( adc.isStreamOpen() ) adc.closeStream();
      return 0;
    }

**Qt中的应用**

功能：  
1左声道  
2右声道  
3双声道

封装一个类，叫ThreadRecord，在多线程中使用RrAudio，当然是继承QThread：

class ThreadRecord :public QThread
    {
    public:
        ThreadRecord();
        static int record(void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames, double streamTime, RtAudioStreamStatus status, void *userData);
        bool flag;
        int type;//通过type进行判断是使用左声道、右声道、双声道
    
    protected:
        void run();
    private:
        RtAudio adc;
        RtAudio::StreamParameters input;
        RtAudio::StreamParameters output;
    };

实现threadrecord.cc:

int ThreadRecord::record(void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames, double streamTime, RtAudioStreamStatus status, void *userData)
    {
        if (status)
            cout << "Stream overflow detected!" << std::endl;
    
        short* output = static_cast<short*>(outputBuffer);
        short* input = static_cast<short*>(inputBuffer);
        short n = nBufferFrames;
    
        int i = *(static_cast<int*>(userData));
    
        if(i == 2) {
            for (i = 0; i < nBufferFrames; i += 1) {
                output[i] = input[i];
            }
        } else {
            for (; i < nBufferFrames; i += 2) {
                output[i] = input[i];
            }
        }
    
        return 0;
    }
    
    void ThreadRecord::run()
    {
        //adc为成员变量：RtAudio adc_;
        // adc_.getDeviceCount()获得音频设备数量
        for(int i = 0 ; i < adc_.getDeviceCount() ; i++)
        {
            qDebug()<< i << adc_.getDeviceInfo(i).name.c_str();
        }
    
        if (adc_.getDeviceCount() < 1) {
            cout << "\nNo audio devices found!\n";
            exit( 0 );
        }
    
        //adc_.getDefaultInputDevice();获得默认输入设备
        input.deviceId = adc_.getDefaultInputDevice();
        input.nChannels = 2;
        input.firstChannel = 0;
    
        output.deviceId = adc_.getDefaultOutputDevice();
        output.nChannels = 2;
        output.firstChannel = 0;
    
        unsigned int sampleRate = 44100;
        unsigned int bufferFrames = 256; 
        try {
            adc_.openStream(&output, &input, RTAUDIO_SINT16, sampleRate,
                           &bufferFrames, &record, static_cast<void*>(&type),
                           NULL, &ErrorCallback);
            adc_.startStream();
        }
        catch (RtAudioError& e) {
            e.printMessage();
            exit(0);
        }
    
        while (flag);
    
        try {
            adc_.stopStream();
        }
        catch (RtAudioError& e) {
            e.printMessage();
        }
        if (adc_.isStreamOpen())
            adc_.closeStream();
    
    }

使用，为了节省篇幅，只写一个函数：  
type=0 左声道  
type=1 右声道  
type=2 双声道

void Recording::onLeftSoundButtonClicked()
    {
        if (thread_record.isRunning())
            thread_record.exit(0);
        thread_record.flag = true;
        thread_record.type = 0;
        thread_record.start();
    }

[http_www.music.mcgill.ca_gary_rtaudio]: http://www.music.mcgill.ca/~gary/rtaudio/
[https_github.com_thestk_rtaudio]: https://github.com/thestk/rtaudio