Windows + Qt and how to capture webcam feed without OpenCV - windows

Question

I'm fighting with this problem from a long time.
I can't get OpenCV to work, and I have follow a lot of tutorials about it and how to use in Qt, so I get tired and I want to avoid the use of OpenCV for this.
Now, my requirement or question... I need to show a webcam feed (real time video, without audio) in a Qt GUI application with only one button: "Take Snapshot" which, obviusly, take a picture from the current feed and store it.
That's all.
Is there anyway to get this done without using OpenCV ?
System specification:
Qt 4.8
Windows XP 32 bits
USB 2.0.1.3M UVC WebCam (the one I'm using now, it should support other models too)
Hope anybody can help me with this because I'm getting crazy.
Thanks in advance!

Answer 1

Ok, I finally did it, so I will post here my solution so we have something clear about this.
I used a library called 'ESCAPI': http://sol.gfxile.net/escapi/index.html
This provide a extremely easy way to capture frames from the device. With this raw data, I just create a QImage which later show in a QLabel.
I created a simple object to handle this.
#include <QDebug>
#include "camera.h"
Camera::Camera(int width, int height, QObject *parent) :
QObject(parent),
width_(width),
height_(height)
{
capture_.mWidth = width;
capture_.mHeight = height;
capture_.mTargetBuf = new int[width * height];
int devices = setupESCAPI();
if (devices == 0)
{
qDebug() << "[Camera] ESCAPI initialization failure or no devices found";
}
}
Camera::~Camera()
{
deinitCapture(0);
}
int Camera::initialize()
{
if (initCapture(0, &capture_) == 0)
{
qDebug() << "[Camera] Capture failed - device may already be in use";
return -2;
}
return 0;
}
void Camera::deinitialize()
{
deinitCapture(0);
}
int Camera::capture()
{
doCapture(0);
while(isCaptureDone(0) == 0);
image_ = QImage(width_, height_, QImage::Format_ARGB32);
for(int y(0); y < height_; ++y)
{
for(int x(0); x < width_; ++x)
{
int index(y * width_ + x);
image_.setPixel(x, y, capture_.mTargetBuf[index]);
}
}
return 1;
}
And the header file:
#ifndef CAMERA_H
#define CAMERA_H
#include <QObject>
#include <QImage>
#include "escapi.h"
class Camera : public QObject
{
Q_OBJECT
public:
explicit Camera(int width, int height, QObject *parent = 0);
~Camera();
int initialize();
void deinitialize();
int capture();
const QImage& getImage() const { return image_; }
const int* getImageRaw() const { return capture_.mTargetBuf; }
private:
int width_;
int height_;
struct SimpleCapParams capture_;
QImage image_;
};
#endif // CAMERA_H
It's so simple, but just for example purposes.
The use should be something like:
Camera cam(320, 240);
cam.initialize();
cam.capture();
QImage img(cam.getImage());
ui->label->setPixmap(QPixmap::fromImage(img));
Of course, you can use a QTimer and update the frame in QLabel and you will have video there...
Hope it help! and thanks Nicholas for your help!