Qt--使用RtAudio进行录音以及播放

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/

github地址：

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, ¶meters, 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();
}