在使用Qt 5.9.4的Fedora上，我无法同时记录和播放音频 [英] On Fedora using Qt 5.9.4, I'm unable to simultaneously record and play audio at the same time

问题描述

我正在尝试用Qt编写一个程序，该程序同时记录来自麦克风的音频并同时播放.我使用的是Qt 5.9.4，我使用的是Fedora 29(无法更新到最新版本，因为我们的生产环境是Fedora 29-无法更新，已经问过老板了.)

I'm trying to write a program in Qt that simultaneously records audio from a microphone and plays it back at the same time. I'm using Qt 5.9.4 and I'm on Fedora 29 (can't update to latest version as our production environment is Fedora 29 -- can't update it, have already asked boss).

我写了一些准系统代码，如下所示.但是每次我运行该程序时，都会收到以下错误消息:

I have some barebones code written, as you can see below. But everytime I run the program, I get the following error message:

using null output device, none available
using null input device, none available

我已经安装了每个qt5 *软件包.我也安装了alsa-utils和脉冲音频.

I've installed every qt5* package. I have alsa-utils and pulse audio installed as well.

我也研究了这些或多或少帮助了我但不能解决我的问题的东西:

I have also looked at these which more or less helped me but did not solve my problem:

• Qt-如何同时录制和播放声音
• https://forum.qt.io/topic/10399/如何同时录制和播放声音/5
• https://www.qtcentre.org/threads/45300-如何同时录制和播放声音
• Qt-无音频输出设备-Yocto/poky
• Qt +柯南=使用空输出设备，无可用

我不知道这是与Fedora有关的问题还是与Qt有关的问题.请帮忙！

I don't know if this is a fedora related issue or a Qt related issue. Please help!

myaudiorecorder.h:

myaudiorecorder.h:

 #ifndef MYAUDIORECORDER_H
 #define MYAUDIORECORDER_H

#include <QAudioFormat>
#include <QAudioDeviceInfo>
#include <QTextStream>
#include <QAudioInput>
#include <QAudioOutput>
#include <QObject>

class MyAudioRecorder : public QObject
{
    Q_OBJECT

public:
    MyAudioRecorder();

    QAudioFormat formatIn;
    QAudioFormat formatOut;

    QAudioInput *m_audioInput;
    QAudioOutput *m_audioOutput;

    QAudioDeviceInfo m_InputDevice;
    QAudioDeviceInfo m_OutputDevice;

    QIODevice *m_input;
    QIODevice *m_output;

    QAudioDeviceInfo deviceIn;
    QAudioDeviceInfo deviceOut;

    void getFormat();
    void createAudioInput();
    void createAudioOutput();
    void beginAudio();

};

#endif // MYAUDIORECORDER_H

myaudiorecorder.cpp:

myaudiorecorder.cpp:

#include "myaudiorecorder.h"

MyAudioRecorder::MyAudioRecorder() {
    getFormat();
    createAudioInput();
    createAudioOutput();
}


void MyAudioRecorder::getFormat(){
    formatIn.setSampleSize(8);
    formatIn.setCodec("audio/pcm");
    formatIn.setByteOrder(QAudioFormat::LittleEndian);
    formatIn.setSampleType(QAudioFormat::UnSignedInt);

    deviceIn = QAudioDeviceInfo::availableDevices(QAudio::AudioInput).at(1);
    if(!deviceIn.isFormatSupported(formatIn)){
    QTextStream(stdout) << " default formatIn not supported " << endl;
    formatIn = deviceIn.nearestFormat(formatIn);
    } else {
    QTextStream(stdout) << " default formatIn supported " << endl;
    }

    deviceOut = QAudioDeviceInfo::availableDevices(QAudio::AudioOutput).at(0);
    if(!deviceOut.isFormatSupported(formatOut)) {
    QTextStream(stdout) << "1. default formatOut not supported " << endl;
    formatOut = deviceOut.nearestFormat(formatOut);
    }

}


void MyAudioRecorder::createAudioInput(){
    m_audioInput = new QAudioInput(m_InputDevice, formatIn, 0);
}

void MyAudioRecorder::createAudioOutput(){
    m_audioOutput = new QAudioOutput(m_OutputDevice, formatOut, 0);
}

void MyAudioRecorder::beginAudio(){
    m_output = m_audioOutput->start();
    m_input = m_audioInput->start();
}

推荐答案

void MyAudioRecorder::beginAudio(){
    m_output = m_audioOutput->start();
    m_audioInput->start(m_output);


   //Above should do the trick but do check the volume, state and error if any:
   qDebug() << "m_audioInput: volume=" <<  m_audioInput->volume()
            << ", state=" << m_audioInput->state()
            << ", error=" << m_audioInput->error();
   qDebug() << "m_audioOutput: volume=" <<  m_audioOutput->volume()
            << ", state=" << m_audioOutput->state()
            << ", error=" << m_audioOutput->error();

}

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