testvideo.c

基于SDL的framegrabber适用于简单的UI下的webcam应用开发

/* 

    TestVideo - SDL_bgrab Sample Player

*/

#ifdef WIN32
 #include <windows.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <ctype.h>

#include <SDL/SDL.h>

#include "SDL/SDL_bgrab.h"

#define DEFAULT_W	640
#define DEFAULT_H	480

/* Commandline configurable items */

char *bgrab_device = NULL;
int framerate = 60;
int deinterlace = 1;
int channel = 1;
int mode = 1;
int region = 1;
int frequency = 1;

char *channel_name[3] = {"Tuner","Composite","SVideo"};
char *mode_name[3] = {"PAL","NTSC","SECAM"};
char *deinterlace_name[4] = {"none","blend","smart blend","smooth blend"};

/* Drawing loop */

void Draw(SDL_Surface *screen, tSDL_bgrab *bgrab)
{
 SDL_Event event; 
 int inloop;
   
 /* Black screen */
 SDL_FillRect(screen,NULL,0);
 SDL_UpdateRect(screen,0,0,0,0);
  
 inloop=1;
 while (inloop) {
    
  /* Check for events */
  while ( SDL_PollEvent(&event) ) {
   switch (event.type) {
    case SDL_KEYDOWN:
     if (event.key.keysym.sym == 'd') {
      deinterlace = ((deinterlace + 1) % 4) ;
      fprintf (stderr,"Deinterlace method: %i (%s)\n",deinterlace,deinterlace_name[deinterlace]);
     } else
     if (event.key.keysym.sym == 'c') {
      channel = ((channel + 1) % 3) ;
      bgrabSetChannel(bgrab,channel,mode);
      fprintf (stderr,"Input Channel: %i (%s)\n",channel,channel_name[channel]);
     } else
     if (event.key.keysym.sym == 'm') {
      mode = ((mode + 1) % 3) ;
      bgrabSetChannel(bgrab,channel,mode);
      fprintf (stderr,"Video Mode: %i (%s)\n",mode,mode_name[mode]);
     } else
     if (event.key.keysym.sym == 'r') {
      region = ((region + 1) % 9) ;
      bgrabSetFrequency(bgrab,region,frequency);
      fprintf (stderr,"Frequency Region: %i\n",region);
     } else
     if (event.key.keysym.sym == 'f') {
      frequency = ((frequency + 1) % 128) ;
      bgrabSetFrequency(bgrab,region,frequency);
      fprintf (stderr,"Frequency Index: %i\n",frequency);
     } else
     if (event.key.keysym.sym == SDLK_ESCAPE) {
      inloop=0;
     }
     break;     
    case SDL_QUIT:
     inloop=0;
     break;
    }
   }

   /* Blit Video screen */
   if (bgrabBlitFramebuffer(bgrab, screen, deinterlace) ) {
    /* Display by updating display */
    SDL_UpdateRect(screen,0,0,0,0);
   }
    
   /* Delay to limit rate */                   
   SDL_Delay(1000/framerate);
   
 }
}

void PrintUsage()
{
 fprintf (stderr,"Usage: TestVideo [SDL parameters] [Video parameters]\n");
 fprintf (stderr," SDL parameters\n");
 fprintf (stderr,"  -width [i]		Set screen width (default: %i)\n",DEFAULT_W);
 fprintf (stderr,"  -height [i]		Set_screen height (default: %i)\n",DEFAULT_H);
 fprintf (stderr,"  -bpp [i]		Set [i] bits per pixel\n");
 fprintf (stderr,"  -warp			Use hardware palette\n");
 fprintf (stderr,"  -hw			Use hardware surface\n");
 fprintf (stderr,"  -fullscreen		Go into fullscreen mode\n");
 fprintf (stderr," Video Parameters\n");
 fprintf (stderr,"  -device [s]		Video device to use\n");
 fprintf (stderr," Program Parameters\n");
 fprintf (stderr,"  -framerate [i]	Target framerate for screen display\n");
}

#ifdef WIN32
 extern char ** __argv;
 extern int __argc;
 int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
#else // non WIN32
 int main ( int argc, char *argv[] )
#endif
{
	SDL_Surface *screen;
	int w, h;
	int desired_bpp;
	Uint32 bgrab_flags;
#ifdef WIN32
	int argc;
	char **argv;

	argv = __argv;
	argc = __argc;
#endif
	tSDL_bgrab bgrab;

	/* Title */
	fprintf (stderr,"SDL_bgrab Sample Video Player - LGPL, A. Schiffler, [e-mail]\n\n");

	/* Set default options and check command-line */
	w = DEFAULT_W;
	h = DEFAULT_H;
	desired_bpp = 0;
	bgrab_flags = 0;
	while ( argc > 1 ) {

		/* SDL specific arguments */
		
		if ( strcmp(argv[1], "-width") == 0 ) {
			if ( argv[2] && ((w = atoi(argv[2])) > 0) ) {
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,
				"The -width option requires an argument\n");
				exit(1);
			}
		} else
		if ( strcmp(argv[1], "-height") == 0 ) {
			if ( argv[2] && ((h = atoi(argv[2])) > 0) ) {
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,"The -height option requires an argument\n");
				exit(1);
			}
		} else
		if ( strcmp(argv[1], "-bpp") == 0 ) {
			if ( argv[2] ) {
				desired_bpp = atoi(argv[2]);
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,"The -bpp option requires an argument\n");
				exit(1);
			}
		} else
		if ( strcmp(argv[1], "-warp") == 0 ) {
			bgrab_flags |= SDL_HWPALETTE;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-hw") == 0 ) {
			bgrab_flags |= SDL_HWSURFACE;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-fullscreen") == 0 ) {
			bgrab_flags |= SDL_FULLSCREEN;
			argv += 1;
			argc -= 1;
		} else

		
		/* Video specific arguments */

		if ( strcmp(argv[1], "-device") == 0 ) {
			if (argv[2]) {
				bgrab_device = strdup(argv[2]);
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,"The -device option requires an argument\n");
				exit(1);
			}
		} else

		/* Program specific arguments */
		
		if ( strcmp(argv[1], "-framerate") == 0 ) {
			if (argv[2]) {
				framerate = atoi(argv[2]);
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,"The -framerate option requires an argument\n");
				exit(1);
			}
		} else {
			PrintUsage();
			exit(0);
			break;
		}
	}

	/* Force double buffering */
	bgrab_flags |= SDL_DOUBLEBUF;

	/* Check/Adjust Video parameters */
	if (bgrab_device==NULL) {
	 bgrab_device=strdup("/dev/v4l/video0");
	 fprintf(stderr,"Defaulting to device '%s'.\n",bgrab_device);
        }
        if ((framerate<1) || (framerate>300)) {
	 fprintf (stderr,"Bad framerate (%i). Use a value from 1 to 300.\n",framerate);
	 PrintUsage();
         exit(1);
	}        
        
	/* Initialize SDL */
	if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
		exit(1);
	}
	atexit(SDL_Quit);			/* Clean up on exit */

	/* Initialize the display */
	screen = SDL_SetVideoMode(w, h, desired_bpp, bgrab_flags);
	if ( screen == NULL ) {
		fprintf(stderr, "Couldn't set %dx%dx%d bgrab mode: %s\n",
					w, h, desired_bpp, SDL_GetError());
		exit(1);
	}

	/* Set the window manager title bar */
	SDL_WM_SetCaption("TestVideo", "testbgrab");

	/* Start grabbing */
	bgrabOpen(&bgrab,bgrab_device);
		
	/* Print some device info */
	bgrabPrintInfo(&bgrab);

	/* Configure card */
	bgrabSetChannel(&bgrab,channel,mode);
        fprintf (stderr,"Input Channel: %i (%s)\n",channel,channel_name[channel]);
        fprintf (stderr,"Video Mode: %i (%s)\n",mode,mode_name[mode]);
        fprintf (stderr,"Frequency Region: %i\n",region);
        fprintf (stderr,"Frequency Index: %i\n",frequency);

        /* Deinterlace Info */        
        fprintf (stderr,"Deinterlace method: %i (%s)\n",deinterlace,deinterlace_name[deinterlace]);
	
	/* Keyboard info */
	fprintf (stderr,"\nKeyboard:\n\tESC = quit\n\tm = video mode\n\tc = input channel\n\td = deinterlace mode\n\tr = frequency region\n\tf = frequency\n\n");
	/* Start grabbing */
	bgrabStart(&bgrab,640,480 , 1);
	
	/* Do all the drawing work */
	Draw (screen, &bgrab);
		
	/* Stop grabbing */
	bgrabStop(&bgrab);
	bgrabClose(&bgrab);
	
	return(0);
}