hyperion.ng/include/grabber/V4L2Grabber.h

#pragma once

// stl includes
#include <string>
#include <vector>

// Qt includes
#include <QObject>
#include <QSocketNotifier>

// util includes
#include <utils/Image.h>
#include <utils/ColorRgb.h>
#include <utils/PixelFormat.h>
#include <utils/VideoMode.h>
#include <utils/ImageResampler.h>

// grabber includes
#include <grabber/VideoStandard.h>

/// Capture class for V4L2 devices
///
/// @see http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html
class V4L2Grabber : public QObject
{
    Q_OBJECT

public:
    V4L2Grabber(const std::string & device,
            int input,
            VideoStandard videoStandard, PixelFormat pixelFormat,
            int width,
            int height,
            int frameDecimation,
            int horizontalPixelDecimation,
            int verticalPixelDecimation);
    virtual ~V4L2Grabber();

public slots:
    void setCropping(int cropLeft,
                     int cropRight,
                     int cropTop,
                     int cropBottom);

    void set3D(VideoMode mode);

    void setSignalThreshold(double redSignalThreshold,
                    double greenSignalThreshold,
                    double blueSignalThreshold,
                    int noSignalCounterThreshold);

    void start();

    void stop();

signals:
    void newFrame(const Image<ColorRgb> & image);

private slots:
    int read_frame();

private:
    void open_device();

    void close_device();

    void init_read(unsigned int buffer_size);

    void init_mmap();

    void init_userp(unsigned int buffer_size);

    void init_device(VideoStandard videoStandard, int input);

    void uninit_device();

    void start_capturing();

    void stop_capturing();

    bool process_image(const void *p, int size);

    void process_image(const uint8_t *p);

    int xioctl(int request, void *arg);

    void throw_exception(const std::string &error);

    void throw_errno_exception(const std::string &error);

private:
    enum io_method {
            IO_METHOD_READ,
            IO_METHOD_MMAP,
            IO_METHOD_USERPTR
    };

    struct buffer {
            void   *start;
            size_t  length;
    };

private:
    const std::string _deviceName;
    const io_method _ioMethod;
    int _fileDescriptor;
    std::vector<buffer> _buffers;

    PixelFormat _pixelFormat;
    int _width;
    int _height;
    int _lineLength;
    int _frameByteSize;
    int _frameDecimation;
    int _noSignalCounterThreshold;

    ColorRgb _noSignalThresholdColor;

    int _currentFrame;
    int _noSignalCounter;

    QSocketNotifier * _streamNotifier;

    ImageResampler _imageResampler;
};