QCameraInfo and OpenCV

[QtCoder87]

Dear Community,

I have a problem:

It is my Settings Widget. I have Audio In, Audio Out and Video In (Webcam).

opencv is working. But how can I open cv::VideoCapture with the Device Name of QCameraInfo? I am using Visual Studio Community 2019 and Windows 10.
VListWidgetItem is similar to QListWidgetItem but instead of using QVariant it uses std::any to store data.

KSecureSettings.hpp

#pragma once

#include <QWidget>
#include "ui_KSecureSettings.h"
#include<InternationalizationLib/language.hpp>
#include<QAudioDeviceInfo>
#undef max
#include"toml.hpp"
#include"VListWidgetItem.hpp"
#include<QCameraInfo>
#include<qpoint.h>
#include<qmenu.h>
#include<QSound>
#include<QAudioOutput>
#include<qfile.h>
#include<opencv2/opencv.hpp>
#include<QMessageBox>

class KSecureSettings : public QWidget
{
	Q_OBJECT

public:
	KSecureSettings(const lang::Language& lang,toml::table* table, QWidget *parent = Q_NULLPTR);
	~KSecureSettings();

protected:
	void setupLanguage();
	void setupSettings();
	void setupCallbacks();

	void testSound();
	void webcamtest();
	void outputContextMenu(const QPoint& pos);
	void webcamContextMenu(const QPoint& pos);

	void tabChanged(int index);

private:
	Ui::KSecureSettings ui;
	const lang::Language& language;
	toml::table* settings = nullptr;
	QAudioOutput* output = nullptr;
	QFile* file = nullptr;
};

and
KSecureSettings.cpp

#include "KSecureSettings.hpp"

#ifdef _WIN32
#ifdef _DEBUG
#pragma comment(lib,"opencv_world430d.lib")
#else
#pragma comment(lib,"opencv_world430.lib")
#endif
#endif

KSecureSettings::KSecureSettings(const lang::Language& lang,toml::table* table, QWidget *parent)
	: language(lang),settings(table), QWidget(parent)
{
	ui.setupUi(this);
	this->setupLanguage();
	this->setupSettings();
	this->setupCallbacks();
}

KSecureSettings::~KSecureSettings()
{
}

void KSecureSettings::setupLanguage()
{
	this->setWindowTitle(QString::fromStdU32String(this->language["OptionsForm"]["Caption"]["title"]));
	this->ui.btnOK->setText(QString::fromStdU32String(this->language["OptionsForm"]["Caption"]["btnok"]));
	this->ui.btnCancel->setText(QString::fromStdU32String(this->language["OptionsForm"]["Caption"]["btncancel"]));
	this->ui.tabWidget->setTabText(0, QString::fromStdU32String(this->language["OptionsForm"]["Tabs"]["one"]));
	this->ui.tabWidget->setTabText(1, QString::fromStdU32String(this->language["OptionsForm"]["Tabs"]["two"]));
	this->ui.tabWidget->setTabText(2, QString::fromStdU32String(this->language["OptionsForm"]["Tabs"]["three"]));
	this->ui.tabWidget->setTabText(3, QString::fromStdU32String(this->language["OptionsForm"]["Tabs"]["four"]));
	this->ui.grp_stun->setTitle(QString::fromStdU32String(this->language["OptionsForm"]["Stun"]["grp_stun"]));
	this->ui.grp_nat->setTitle(QString::fromStdU32String(this->language["OptionsForm"]["NAT"]["grp_nat"]));
	this->ui.lbl_ipv4->setText(QString::fromStdU32String(this->language["OptionsForm"]["Stun"]["ipv4"]));
	this->ui.lbl_ipv6->setText(QString::fromStdU32String(this->language["OptionsForm"]["Stun"]["ipv6"]));
	this->ui.lbl_port->setText(QString::fromStdU32String(this->language["OptionsForm"]["Stun"]["port"]));
	this->ui.lbl_ipv4_2->setText(this->ui.lbl_ipv4->text());
	this->ui.lbl_ipv6_2->setText(this->ui.lbl_ipv6->text());
	this->ui.lbl_port_2->setText(this->ui.lbl_port->text());
	this->ui.lbl_input->setText(QString::fromStdU32String(this->language["OptionsForm"]["Multimedia"]["lbl_input"]));
	this->ui.lbl_output->setText(QString::fromStdU32String(this->language["OptionsForm"]["Multimedia"]["lbl_output"]));
	this->ui.lbl_webcam->setText(QString::fromStdU32String(this->language["OptionsForm"]["Multimedia"]["lbl_webcam"]));
}

void KSecureSettings::setupSettings()
{
	const auto& sys = *this->settings;
	this->ui.txt_ip4stun->setText(QString::fromStdString(sys["server"]["stun"]["ipv4"].value_or<std::string>("")));
	this->ui.txt_ip6stun->setText(QString::fromStdString(sys["server"]["stun"]["ipv6"].value_or<std::string>("")));
	this->ui.txt_portstun->setText(QString::number(sys["server"]["stun"]["port"].value_or<uint32_t>(0)));
	//
	this->ui.txt_ip4nat->setText(QString::fromStdString(sys["server"]["nat"]["ipv4"].value_or<std::string>("")));
	this->ui.txt_ip6nat->setText(QString::fromStdString(sys["server"]["nat"]["ipv6"].value_or<std::string>("")));
	this->ui.txt_portnat->setText(QString::number(sys["server"]["nat"]["port"].value_or<uint32_t>(0)));

	auto ilist = QAudioDeviceInfo::availableDevices(QAudio::Mode::AudioInput);
	auto olist = QAudioDeviceInfo::availableDevices(QAudio::Mode::AudioOutput);
	for (auto& item : ilist) {
		
		auto* li = new VListWidgetItem(QIcon(":/KSecureDesktopQT/speaker.png"),item.deviceName(),item);
		this->ui.lw_input->addItem(li);
	}
	for (auto& item : olist) {
		auto* li = new VListWidgetItem(QIcon(":/KSecureDesktopQT/speaker.png"), item.deviceName(), item);
		this->ui.lw_output->addItem(li);
	}
	auto vlist = QCameraInfo::availableCameras();
	for (auto& item : vlist) {
		auto* li = new VListWidgetItem(QIcon(":/KSecureDesktopQT/camera.png"), item.deviceName(), item);
		this->ui.lw_webcam->addItem(li);
	}
	
}

void KSecureSettings::setupCallbacks()
{
	connect(this->ui.lw_output, &QListWidget::customContextMenuRequested, this, &KSecureSettings::outputContextMenu);
	connect(this->ui.lw_webcam, &QListWidget::customContextMenuRequested, this, &KSecureSettings::webcamContextMenu);
	connect(this->ui.tabWidget, &QTabWidget::currentChanged, this, &KSecureSettings::tabChanged);
}

void KSecureSettings::testSound()
{
	auto* item = this->ui.lw_output->selectedItems()[0];
	//QSound* s = new QSound("testsound.wav");
	//s->play();
	auto* citem = static_cast<VListWidgetItem*>(item);
	auto dev = citem->getData<QAudioDeviceInfo>();
	auto name = dev.deviceName();
	QAudioFormat format;
	format.setCodec("audio/pcm");
	format.setSampleRate(8000);
	format.setChannelCount(1);
	format.setSampleSize(8);
	format.setByteOrder(QAudioFormat::LittleEndian);
	format.setSampleType(QAudioFormat::UnSignedInt);
	this->output = new QAudioOutput(dev, format);
	this->file = new QFile(":/KSecureDesktopQT/testsound.wav");
	this->file->open(QIODevice::ReadOnly);
	this->output->start(this->file);

}

void KSecureSettings::webcamtest()
{
	using namespace cv;
	VideoCapture cap;
	if (!cap.open(0)) {
		QMessageBox::critical(nullptr, "ERROR", "Could not open Video Input");
		return;
	}
	for (;;) {
		Mat frame;
		cap >> frame;
		if (frame.empty()) break; //Video empty;
		imshow("TEST", frame);
		if (waitKey(10) == 27) break;
	}
}

void KSecureSettings::outputContextMenu(const QPoint& pos)
{
	QMenu ctx;
	ctx.addAction(QString::fromStdU32String(this->language["OptionsForm"]["ContextOutput"]["testsound"]), [&]() {this->testSound(); });
	QAction *stop = new QAction(QString::fromStdU32String(this->language["OptionsForm"]["ContextOutput"]["stopsound"]));
	connect(stop, &QAction::triggered, this, [&]() {this->output->stop(); });
	if (!this->output)
		stop->setEnabled(false);
	ctx.addAction(stop);
	ctx.exec(QCursor::pos());
}

void KSecureSettings::webcamContextMenu(const QPoint& pos)
{
	QMenu ctx;
	ctx.addAction(QString::fromStdU32String(this->language["OptionsForm"]["ContextVideo"]["webcamtest"]), [&]() {this->webcamtest(); });
	ctx.exec(QCursor::pos());
}

void KSecureSettings::tabChanged(int index)
{
	if (index != 3)
		return;
	if (this->ui.lw_webcam->selectedItems().count() < 1)
		return;
	auto dev = (static_cast<VListWidgetItem*>((this->ui.lw_webcam->selectedItems()[0]))->getData<QCameraInfo>());
	
	cv::VideoCapture cap(dev.deviceName().toStdString());
	bool t = cap.isOpened();
}

[SGaist]

Hi and welcome to devnet,

You should rather enumerate the cameras with OpenCV as well so you will be consistent to access them.