영상 캡쳐하는 프로그래밍 질문입니다

로지텍 퀵캠으로 영상처리를 하고 있는 학생입니다.
이미지 캡쳐하고 window하나 만들어서 보여주는 프로그램인데

return_value = ioctl(fd, VIDIOCSPICT, &pic);
if ( return_value < 0 )
{
fprintf(stderr,"Failed to set the image properties\n");
exit(1);
}

이 부분에서 자꾸 오류가 나면서 창이 그냥 닫힙니다. ㅠㅠ
(VIDIOCGPICT로 미리 pic도 얻었습니다)
나름대로 요것조것 해본결과 palette부분 설정이 바뀌지 않는것 같은데...

혹시해서 원래 설정대로 palette =VIDEO_PALETTE_YUV420P
로 하면 이 오류는 나지 않는데, 대신에
XIO: fatal IO error 14(Bad address) on X server ":0.0"
after 13 requests (6 known processed) with 0 events rremaining.
이라는 메시지가 나면서 창이 그냥 닫힙니다.
설마 x-window에서는 yuv포맷으론 display가 안되나요??

영상 처리 첨이라 힘드네요ㅠㅠ 도와주세요~~~

소스 첨부 합니다-------------------------

#include <X11/Xlib.h>
#include <unistd.h>
#include <stdio.h>
#include <linux/videodev.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

char *v4l_init();
char *v4l_capture();
int fd;
unsigned char *map;
struct video_mmap v_map;
struct video_mbuf m_buf;

int main( int argc, char * argv[] )
{
  Display *display;
  Window window;
  GC gc;
  Visual *visual;
  XImage *display_image;
  unsigned char *buffer;
  int window_width,window_height;

  display = XOpenDisplay("localhost:0.0");

/* window size 768*480 */
  window_width = 768; window_height = 480;
  window = XCreateSimpleWindow(display, RootWindow(display,0),
			       50, 50, window_width, window_height, 3,
			       BlackPixel(display,0), WhitePixel(display,0));
  gc = XCreateGC(display, window, 0L, (XGCValues *) NULL);

  XMapWindow(display, window);
  XFlush(display);

  buffer = v4l_init(); /* video capture device initialize */

  while ( 1 )
  {
    buffer = v4l_capture(); /* video capture */

/*
 * image create - depth = default(window depth)
 *                size = 768 * 480
 *                RGB color 32bit (blue, green, red, alpha)
 */
    display_image = XCreateImage(display, DefaultVisual(display, 0), 
				 DefaultDepth(display, 0), ZPixmap, 0,
				 buffer, 768, 480, 32, 0);
    display_image->byte_order = LSBFirst;
/* display image */
    XPutImage(display, window, gc, display_image, 0, 0, 0, 0, 768, 480);
  }

  return 0;
  
}



char *v4l_init()
{
  int width, height;
  int depth, palette;
  int return_value;
  char *device;

  struct video_capability cap;
  struct video_channel chan;
  struct video_window win;
  struct video_picture pic;

/* capture device is video0 */
  device = "/dev/video0";

  if ( (fd = open(device, O_RDONLY)) < 0 )
  {
    fprintf(stderr, "video device %s could not be opened\n", device);
    exit(1);
  }

  return_value = ioctl(fd , VIDIOCGCAP, &cap);
  if ( return_value < 0 )
  {
    fprintf(stderr, "ioctl on VIDIOCGCAP failled\n");
    exit(1);
  }

/* capture channel is 0 */
  chan.channel = 0;
 // chan.flags = 0;
  chan.type = VIDEO_TYPE_CAMERA;
  chan.norm = VIDEO_MODE_NTSC;
  return_value = ioctl(fd, VIDIOCSCHAN, &chan);
  if ( return_value < 0 )
  {
    fprintf(stderr, "ioctl on VIDIOCSCHAN failed\n");
    exit(1);
  }

  return_value = ioctl(fd, VIDIOCGWIN, &win);

/* capture image depth is 32 and palette is rgb32 */
  depth = 32;
  palette = VIDEO_PALETTE_RGB32;

  width = win.width = cap.maxwidth;
  height = win.height = cap.maxheight;
  win.x = win.y = win.chromakey = win.flags = 0;
  return_value = ioctl(fd, VIDIOCSWIN, &win);
  if ( return_value < 0 )
  {
    fprintf(stderr,"ioctl on VIDIOCSWIN failed\n");
    exit(1);
  }

  return_value = ioctl(fd, VIDIOCGPICT, &pic);
  if ( return_value < 0 )
  { 
    fprintf(stderr,"Failed to get the image properties\n");
    exit(1);
  }

  printf("depth = %d\n", pic.depth);
 if(pic.palette == VIDEO_PALETTE_YUV420P)
	  printf("2\n");
//  printf("palette = %d\n", pic.palette);
  
  pic.depth = depth;
  pic.palette = palette;

  return_value = ioctl(fd, VIDIOCSPICT, &pic);
  if ( return_value < 0 )
  {
    fprintf(stderr,"Failed to set the image properties\n");
    exit(1);
  }

  return_value = ioctl(fd, VIDIOCGMBUF, &m_buf);
  if ( return_value < 0 )
  {
    fprintf(stderr, "Failed to get information of capture memory space.\n");
    exit(1);
  }

  map = (char*) mmap(0, m_buf.size, PROT_READ, MAP_SHARED, fd, 0);
  if ( map == MAP_FAILED )
  {
    fprintf(stderr,"Failed to get pointer to memory mapped area.\n");
    exit(1);
  }

  v_map.height = height;
  v_map.width = width;

  v_map.format = palette;

/* 4 frame use */
  v_map.frame = 0;
  return_value = ioctl(fd, VIDIOCMCAPTURE, &v_map);
  v_map.frame = 1;
  return_value = ioctl(fd, VIDIOCMCAPTURE, &v_map);
  v_map.frame = 2;
  return_value = ioctl(fd, VIDIOCMCAPTURE, &v_map);
  v_map.frame = 3;
  return_value = ioctl(fd, VIDIOCMCAPTURE, &v_map);

  return map;
}


char *v4l_capture()
{
/* capture frame with 4 frame buffer */
  ioctl(fd, VIDIOCSYNC, &v_map);
  v_map.frame++;
  if ( v_map.frame == 4 )
    v_map.frame = 0;
  ioctl(fd, VIDIOCMCAPTURE, &v_map);

  return map+m_buf.offsets[v_map.frame];
}