delphi - Take screenshot in webcam using VFrames in Console Application -

i'm doing program take picture of webcam using delphi xe2 , vframes achieve this, problem have figured out, in graphic application works fine, when use unit in console application, returns me error saying

first chance exception @ $76b6b727. exception class eaccessviolation message 'access violation @ address 004a271b in module 'console.exe'. read of address 00000260'. process console.exe (3676)

my unit :

unit webcam;  interface  uses sysutils, windows, vcl.imaging.jpeg, vcl.graphics, vsample,   vframes, classes;  type   twebcam = class   private     procedure newvideoframeevent(sender: tobject; width, height: integer;       dataptr: pointer);   public     constructor create;     destructor destroy; override;     procedure capture_webcam(take_name: string);    end;  var   web_image: tvideoimage;   name_screen: string;  implementation  constructor twebcam.create; begin   inherited create; end;  destructor twebcam.destroy; begin   inherited destroy; end;  procedure twebcam.newvideoframeevent(sender: tobject; width, height: integer;   dataptr: pointer); var   bitmap: tbitmap;   name: string; begin   name := name_screen;   if (fileexists(name))   begin     deletefile(pchar(name));   end;   bitmap := tbitmap.create;   bitmap.pixelformat := pf24bit;   web_image.getbitmap(bitmap);   bitmap.savetofile(name);   bitmap.free;   web_image.videostop;   web_image.free; end;  procedure twebcam.capture_webcam(take_name: string); var   list_cams: tstringlist; begin    web_image := tvideoimage.create();    list_cams := tstringlist.create;    web_image.getlistofdevices(list_cams);   if not(list_cams.count = 0)   begin     name_screen := take_name;     web_image.videostart(list_cams[0]);   end;    list_cams.free;    web_image.onnewvideoframe := newvideoframeevent;  end;  end. 

console :

program console;  {$apptype console} {$r *.res}  uses   system.sysutils,   webcam;  var   webcamz: twebcam;  begin   try     webcamz := twebcam.create();     webcamz.capture_webcam('test.jpg');     webcamz.free();   except     on e: exception       writeln(e.classname, ': ', e.message);   end;  end. 

what should ?

the relevent source code vframes unit available on github:

https://github.com/heise/grblize/blob/edge/vframes.pas

https://github.com/heise/grblize/blob/edge/vsample.pas

the tvideoimage.videostart() method has dependancy on application.mainform.handle. console application not have mainform default, alone crash code in console application unless create mainform (which defeats purpose of making console app).

aside that, tvideoimage has dependancy on message loop, creates hidden window receive video notifications used fire onnewvideoframe event. console application not have message loop. , if did, freeing tvideoimage object before event fire anyway, capture_webcam() code not waiting event fire before exiting.

also, tvideosample class (which tvideoimage uses internally) uses directshow api capture images webcam's video stream. directshow com-based api. console application not initializing com before using tvideoimage. alone cause getlistofdevices() fail , return blank list. , if attempted ignore , provide device name anyway, videostart() still crash when tries access com object tvideosample not able create during construction.