C # Video header operations

Underlying operation class:

Using system;
Using system. runtime. interopservices;

Namespace getphoto
{
/// <Summary>
/// Summary of avicapture.
/// </Summary>
Public class showvideo
{
// Call acicap32.dll to read camera data
[Dllimport ("avicap32.dll")]
Public static extern intptr capcreatecapturew.wa (byte [] lpszwindowname, int dwstyle, int X, int y, int nwidth, int nheight, intptr hwndparent, int NID );
[Dllimport ("avicap32.dll")]
Public static extern bool capgetdriverdescriptiona (short wdriver, byte [] lpszname, int cbname, byte [] lpszver, int cbver );
[Dllimport ("user32.dll")]
Public static extern bool sendmessage (intptr hwnd, int wmsg, bool wparam, int lparam );
[Dllimport ("user32.dll")]
Public static extern bool sendmessage (intptr hwnd, int wmsg, short wparam, int lparam );
[Dllimport ("user32.dll")]
Public static extern bool sendmessage (intptr hwnd, int wmsg, short wparam, frameeventhandler lparam );
[Dllimport ("user32.dll")]
Public static extern bool sendmessage (intptr hwnd, int wmsg, int wparam, ref bitmapinfo lparam );
[Dllimport ("user32.dll")]
Public static extern bool sendmessage (intptr hwnd, int wmsg, int wparam, ref capdrivercaps lparam );
[Dllimport ("user32.dll")]
Public static extern int setwindowpos (intptr hwnd, int hwndinsertafter, int X, int y, int CX, int cy, int wflags );
[Dllimport ("avicap32.dll")]
Public static extern int capgetvideoformat (intptr hwnd, intptr psvideoformat, int wsize );

// Some constants
Public const int wm_user = 0x400;
Public const int ws_child = 0x40000000;
Public const int ws_visible = 0x10000000;
Public const int swp_nomove = 0x2;
Public const int swp_nozorder = 0x4;
Public const int wm_cap_driver_connect = wm_user + 10;
Public const int wm_cap_driver_disconnect = wm_user + 11;
Public const int wm_cap_set_callback_frame = wm_user + 5;
Public const int wm_cap_set_preview = wm_user + 50;
Public const int wm_cap_set_previewrate = wm_user + 52;
Public const int wm_cap_set_videoformat = wm_user + 45;
Public const int wm_cap_savedib = wm_user + 25;
Public const int wm_cap_set_overlay = wm_user + 51;
Public const int wm_cap_get_caps = wm_user + 14;
Public const int wm_cap_dlg_videoformat = wm_user + 41;
Public const int wm_cap_dlg_videosource = wm_user + 42;
Public const int wm_cap_dlg_videodisplay = wm_user + 43;
Public const int wm_cap_edit_copy = wm_user + 30;
Public const int wm_cap_set_sequence_setup = wm_user + 64;
Public const int wm_cap_get_sequence_setup = wm_user + 65;


// Structure
[Structlayout (layoutkind. Sequential)]
// Videohdr
Public struct videohdr
{
[Financialas (unmanagedtype. I4)]
Public int lpdata;
[Financialas (unmanagedtype. I4)]
Public int dwbufferlength;
[Financialas (unmanagedtype. I4)]
Public int dwbytesused;
[Financialas (unmanagedtype. I4)]
Public int dwtimecaptured;
[Financialas (unmanagedtype. I4)]
Public int dwuser;
[Financialas (unmanagedtype. I4)]
Public int dwflags;
[Financialas (unmanagedtype. byvalarray, sizeconst = 4)]
Public int [] dwreserved;
}

[Structlayout (layoutkind. Sequential)]
// Bitmapinfoheader
Public struct bitmapinfoheader
{
[Financialas (unmanagedtype. I4)]
Public int32 bisize;
[Financialas (unmanagedtype. I4)]
Public int32 biwidth;
[Financialas (unmanagedtype. I4)]
Public int32 biheight;
[Financialas (unmanagedtype. I2)]
Public short biplanes;
[Financialas (unmanagedtype. I2)]
Public short bibitcount;
[Financialas (unmanagedtype. I4)]
Public int32 bicompression;
[Financialas (unmanagedtype. I4)]
Public int32 bisizeimage;
[Financialas (unmanagedtype. I4)]
Public int32 bixpelspermeter;
[Financialas (unmanagedtype. I4)]
Public int32 biypelspermeter;
[Financialas (unmanagedtype. I4)]
Public int32 biclrused;
[Financialas (unmanagedtype. I4)]
Public int32 biclrimportant;
}

[Structlayout (layoutkind. Sequential)]
// Bitmapinfo
Public struct bitmapinfo
{
[Financialas (unmanagedtype. struct, sizeconst = 40)]
Public bitmapinfoheader bmiheader;
[Financialas (unmanagedtype. byvalarray, sizeconst = 1024)]
Public int32 [] bmicolors;
}

[Structlayout (layoutkind. Sequential)]
Public struct capdrivercaps
{
[Financialas (unmanagedtype. U2)]
Public uint16 wdeviceindex;
[Financialas (unmanagedtype. bool)]
Public bool fhasoverlay;
[Financialas (unmanagedtype. bool)]
Public bool fhasdlgvideosource;
[Financialas (unmanagedtype. bool)]
Public bool fhasdlgvideoformat;
[Financialas (unmanagedtype. bool)]
Public bool fhasdlgvideodisplay;
[Financialas (unmanagedtype. bool)]
Public bool fcaptureinitialized;
[Financialas (unmanagedtype. bool)]
Public bool fdriversuppliespalettes;
[Financialas (unmanagedtype. I4)]
Public int hvideoin;
[Financialas (unmanagedtype. I4)]
Public int hvideoout;
[Financialas (unmanagedtype. I4)]
Public int hvideoextin;
[Financialas (unmanagedtype. I4)]
Public int hvideoextout;
}


Public Delegate void frameeventhandler (intptr lwnd, intptr lpvhdr );

// Public Functions
Public static object getstructure (intptr, valuetype structure)
{
Return marshal. ptrtostructure (PTR, structure. GetType ());
}

Public static object getstructure (int ptr, valuetype structure)
{
Return getstructure (New intptr (PTR), structure );
}

Public static void copy (intptr, byte [] data)
{
Marshal. Copy (PTR, Data, 0, Data. Length );
}

Public static void copy (int ptr, byte [] data)
{
Copy (New intptr (PTR), data );
}

Public static int sizeof (object structure)
{
Return marshal. sizeof (structure );
}
}
}

Function operation class:

Using system;
Using system. runtime. interopservices;

Namespace getphoto
{
/// <Summary>
/// Summary of camera.
/// </Summary>

Public class webcamera
{
Private intptr lwndc;
Private intptr mcontrolptr;
Private int mwidth;
Private int mheight;

// Constructor
Public webcamera (intptr handle, int width, int height)
{
Mcontrolptr = handle;
Mwidth = width;
Mheight = height;
}

// Delegate of frame callback
Public Delegate void recievedframeeventhandler (byte [] data );
Public event recievedframeeventhandler recievedframe;
Private showvideo. frameeventhandler mframeeventhandler;

// Close the camera
Public void closewebcam ()
{
This. capdriverdisconnect (this. lwndc );
}

// enable the camera
Public bool startwebcam ()
{
byte [] lpszname = new byte [100];
byte [] lpszver = new byte [100];
try
{< br> showvideo. capgetdriverdescriptiona (0, lpszname, 100, lpszver, 100);
This. lwndc = showvideo. capcreatecapturew.wa (lpszname, showvideo. ws_visible + showvideo. ws_child, 0, 0, mwidth, mheight, mcontrolptr, 0);

If (this. capdriverconnect (this. lwndc, 0 ))
{
This. cappreviewrate (this. lwndc, 66 );

This. cappreview (this. lwndc, true );
This. capoverlay (this. lwndc, true );
Showvideo. bitmapinfo = new showvideo. bitmapinfo ();
Bitmapinfo. bmiheader. bisize = showvideo. sizeof (bitmapinfo. bmiheader );
Bitmapinfo. bmiheader. biwidth = This. mwidth;
Bitmapinfo. bmiheader. biheight = This. mheight;
Bitmapinfo. bmiheader. biplanes = 1;
Bitmapinfo. bmiheader. bibitcount = 24;
This. capsetvideoformat (this. lwndc, ref bitmapinfo, showvideo. sizeof (bitmapinfo ));

This. mframeeventhandler = new showvideo. frameeventhandler (framecallback );
This. capsetcallbackonframe (this. lwndc, this. mframeeventhandler );
Showvideo. setwindowpos (this. lwndc, 0, 0, 0, mwidth, mheight, 6 );
Return true;
}
Else
{
Return false;
}
}
Catch
{
Return false;
}
}

Public void grabimage (string path) // capture a graph to a file
{
Intptr hbmp = marshal. stringtohglobalansi (PATH );
Showvideo. sendmessage (lwndc, showvideo. wm_cap_savedib, 0, hbmp. toint32 ());
}
Public void setcapturesource () // The color Setting dialog box is displayed.
{
Showvideo. capdrivercaps caps = new showvideo. capdrivercaps ();
Showvideo. sendmessage (lwndc, showvideo. wm_cap_get_caps, showvideo. sizeof (CAPs), ref caps );
If (caps. fhasdlgvideosource)
{
Showvideo. sendmessage (lwndc, showvideo. wm_cap_dlg_videosource, 0, 0 );

}
}
Public void setcaptureformat () // The video format Setting dialog box is displayed.
{
Showvideo. capdrivercaps caps = new showvideo. capdrivercaps ();
Showvideo. sendmessage (lwndc, showvideo. wm_cap_get_caps, showvideo. sizeof (CAPs), ref caps );
If (caps. fhasdlgvideosource)
{
Showvideo. sendmessage (lwndc, showvideo. wm_cap_dlg_videoformat, 0, 0 );

}< BR >}< br> Public bool copytoclipboard () // capture the image to the clipboard
{< br> return showvideo. sendmessage (lwndc, showvideo. wm_cap_edit_copy, 0, 0);
}

// The following are private functions
Private bool capdriverconnect (intptr lwnd, short I)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_driver_connect, I, 0 );
}

Private bool capdriverdisconnect (intptr lwnd)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_driver_disconnect, 0, 0 );
}

Private bool cappreview (intptr lwnd, bool F)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_set_preview, F, 0 );
}

Private bool cappreviewrate (intptr lwnd, short WMS)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_set_previewrate, WMS, 0 );
}

Private bool capsetcallbackonframe (intptr lwnd, showvideo. frameeventhandler lpproc)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_set_callback_frame, 0, lpproc );
}

Private bool capsetvideoformat (intptr hcapwnd, ref showvideo. bitmapinfo BMP format, int capformatsize)
{
Return showvideo. sendmessage (hcapwnd, showvideo. wm_cap_set_videoformat, capformatsize, ref BMP format );
}

Private void framecallback (intptr lwnd, intptr lpvhdr)
{
Showvideo. videohdr videoheader = new showvideo. videohdr ();
Byte [] videodata;
Videoheader = (showvideo. videohdr) showvideo. getstructure (lpvhdr, videoheader );
Videodata = new byte [videoheader. dwbytesused];
Showvideo. Copy (videoheader. lpdata, videodata );
If (this. recievedframe! = NULL)
This. recievedframe (videodata );
}
Private bool capoverlay (intptr lwnd, bool F)
{
Return showvideo. sendmessage (lwnd, showvideo. wm_cap_set_overlay, F, 0 );
}

}
}