Can I suggest you a look in my homepage ? I have some source code, examples that people from this mail list sent me some time ago, and I also maintain videodog, a proggie to capture frames from any v4l device. In the latest release there is some effect and image manipulation code too. The url is: http://videodog.cjb.net or http://planeta.terra.com.br/informatica/gleicon/ Regards. ----- Original Message ----- From: "Ken Hirsch" <khirsch11414@xxxxxxxxx> To: <video4linux-list@xxxxxxxxxx> Sent: Tuesday, July 10, 2001 1:56 PM Subject: Simple capture (Newbie Question) > Hello > > I am probably repeating a question that has been asked a 1000 times but > here it goes. I just want to capture an image from my Booktree device > (WinTV card) and manipulate the stream in memory. I don't care about > printing it out to screen. I am certainly a newbie programmer and reading > over the api on the V4L just doesn't sink in enough. > > I've been using the code from below (vgrabber.c by Phil Blundell) however > evrytime I get to the read function the program hangs. I read on the API > page that not all devices can be read from so I might have to use the mmap > funtion. However I have not found an example of this that is easy to > follow for a newbie and was wondering if there was any available. > > Also I am having troubles switching tuners (I am trying to go to Composite > 1 in) can anyone see why this code is failing? > > struct video_channel chan; > > chan.channel=1; > > if (ioctl(fd, VIDIOCGCHAN, &chan) < 0) { > perror("VIDIOCGCHAN"); > fprintf(stderr, "(" FILE " Didn't Work"); > close(fd); > exit(1); > > chan.channel=1; > chan.type=VIDEO_TYPE_CAMERA; > > if (ioctl(fd, VIDIOCSCHAN, &chan) < 0) { > perror("VIDIOGSCHAN"); > fprintf(stderr, "(" FILE " Didn't work"); > close(fd); > exit(1); > > > This code fails at the ioctl VIDIOCSCHAN call. > > Thanks for any help you might be able to offer. > > > int main(void) > { > int fd = open(FILE, O_RDONLY), f; > struct video_capability cap; > struct video_window win; > struct video_picture vpic; > > unsigned char *buffer, *src; > int bpp = 24, r, g, b; > unsigned int i, src_depth; > > if (fd < 0) { > perror(FILE); > exit(1); > } > > if (ioctl(fd, VIDIOCGCAP, &cap) < 0) { > perror("VIDIOGCAP"); > fprintf(stderr, "(" FILE " not a video4linux device?)\n"); > close(fd); > exit(1); > } > > if (ioctl(fd, VIDIOCGWIN, &win) < 0) { > perror("VIDIOCGWIN"); > close(fd); > exit(1); > } > > if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) { > perror("VIDIOCGPICT"); > close(fd); > exit(1); > } > > if (cap.type & VID_TYPE_MONOCHROME) { > vpic.depth=8; > vpic.palette=VIDEO_PALETTE_GREY; /* 8bit grey */ > if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) { > vpic.depth=6; > if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) { > vpic.depth=4; > if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) { > fprintf(stderr, "Unable to find a supported capture format.\n"); > close(fd); > exit(1); > } > } > } > } else { > vpic.depth=24; > vpic.palette=VIDEO_PALETTE_RGB24; > > if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) { > vpic.palette=VIDEO_PALETTE_RGB565; > vpic.depth=16; > > if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) { > vpic.palette=VIDEO_PALETTE_RGB555; > vpic.depth=15; > > if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) { > fprintf(stderr, "Unable to find a supported capture format.\n"); > return -1; > } > } > } > } > > buffer = malloc(win.width * win.height * bpp); > if (!buffer) { > fprintf(stderr, "Out of memory.\n"); > exit(1); > } > > do { > int newbright; > read(fd, buffer, win.width * win.height * bpp); > f = get_brightness_adj(buffer, win.width * win.height, &newbright); > if (f) { > vpic.brightness += (newbright << 8); > if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) { > perror("VIDIOSPICT"); > break; > } > } > } while (f); > > fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height); > > src = buffer; > > for (i = 0; i < win.width * win.height; i++) { > READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b); > fputc(r>>8, stdout); > fputc(g>>8, stdout); > fputc(b>>8, stdout); > } > > close(fd); > } > > __________________________________________________ > Do You Yahoo!? > Get personalized email addresses from Yahoo! Mail > http://personal.mail.yahoo.com/ > > > > _______________________________________________ > Video4linux-list mailing list > Video4linux-list@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/video4linux-list >
