[media] DocBook: Move all media docbook stuff into its own directory

[pandora-kernel.git] / Documentation / DocBook / media / v4l / v4l2grab.c.xml

diff --git a/Documentation/DocBook/media/v4l/v4l2grab.c.xml b/Documentation/DocBook/media/v4l/v4l2grab.c.xml
new file mode 100644 (file)
index 0000000..bed12e4
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/v4l2grab.c.xml
@@ -0,0 +1,164 @@
+<programlisting>
+/* V4L2 video picture grabber
+   Copyright (C) 2009 Mauro Carvalho Chehab &lt;mchehab@infradead.org&gt;
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+ */
+
+#include &lt;stdio.h&gt;
+#include &lt;stdlib.h&gt;
+#include &lt;string.h&gt;
+#include &lt;fcntl.h&gt;
+#include &lt;errno.h&gt;
+#include &lt;sys/ioctl.h&gt;
+#include &lt;sys/types.h&gt;
+#include &lt;sys/time.h&gt;
+#include &lt;sys/mman.h&gt;
+#include &lt;linux/videodev2.h&gt;
+#include "../libv4l/include/libv4l2.h"
+
+#define CLEAR(x) memset(&amp;(x), 0, sizeof(x))
+
+struct buffer {
+        void   *start;
+        size_t length;
+};
+
+static void xioctl(int fh, int request, void *arg)
+{
+        int r;
+
+        do {
+                r = v4l2_ioctl(fh, request, arg);
+        } while (r == -1 &amp;&amp; ((errno == EINTR) || (errno == EAGAIN)));
+
+        if (r == -1) {
+                fprintf(stderr, "error %d, %s\n", errno, strerror(errno));
+                exit(EXIT_FAILURE);
+        }
+}
+
+int main(int argc, char **argv)
+{
+        struct <link linkend="v4l2-format">v4l2_format</link>              fmt;
+        struct <link linkend="v4l2-buffer">v4l2_buffer</link>              buf;
+        struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link>      req;
+        enum <link linkend="v4l2-buf-type">v4l2_buf_type</link>              type;
+        fd_set                          fds;
+        struct timeval                  tv;
+        int                             r, fd = -1;
+        unsigned int                    i, n_buffers;
+        char                            *dev_name = "/dev/video0";
+        char                            out_name[256];
+        FILE                            *fout;
+        struct buffer                   *buffers;
+
+        fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0);
+        if (fd &lt; 0) {
+                perror("Cannot open device");
+                exit(EXIT_FAILURE);
+        }
+
+        CLEAR(fmt);
+        fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        fmt.fmt.pix.width       = 640;
+        fmt.fmt.pix.height      = 480;
+        fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24;
+        fmt.fmt.pix.field       = V4L2_FIELD_INTERLACED;
+        xioctl(fd, VIDIOC_S_FMT, &amp;fmt);
+        if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) {
+                printf("Libv4l didn't accept RGB24 format. Can't proceed.\n");
+                exit(EXIT_FAILURE);
+        }
+        if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480))
+                printf("Warning: driver is sending image at %dx%d\n",
+                        fmt.fmt.pix.width, fmt.fmt.pix.height);
+
+        CLEAR(req);
+        req.count = 2;
+        req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        req.memory = V4L2_MEMORY_MMAP;
+        xioctl(fd, VIDIOC_REQBUFS, &amp;req);
+
+        buffers = calloc(req.count, sizeof(*buffers));
+        for (n_buffers = 0; n_buffers &lt; req.count; ++n_buffers) {
+                CLEAR(buf);
+
+                buf.type        = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory      = V4L2_MEMORY_MMAP;
+                buf.index       = n_buffers;
+
+                xioctl(fd, VIDIOC_QUERYBUF, &amp;buf);
+
+                buffers[n_buffers].length = buf.length;
+                buffers[n_buffers].start = v4l2_mmap(NULL, buf.length,
+                              PROT_READ | PROT_WRITE, MAP_SHARED,
+                              fd, buf.m.offset);
+
+                if (MAP_FAILED == buffers[n_buffers].start) {
+                        perror("mmap");
+                        exit(EXIT_FAILURE);
+                }
+        }
+
+        for (i = 0; i &lt; n_buffers; ++i) {
+                CLEAR(buf);
+                buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory = V4L2_MEMORY_MMAP;
+                buf.index = i;
+                xioctl(fd, VIDIOC_QBUF, &amp;buf);
+        }
+        type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+        xioctl(fd, VIDIOC_STREAMON, &amp;type);
+        for (i = 0; i &lt; 20; i++) {
+                do {
+                        FD_ZERO(&amp;fds);
+                        FD_SET(fd, &amp;fds);
+
+                        /* Timeout. */
+                        tv.tv_sec = 2;
+                        tv.tv_usec = 0;
+
+                        r = select(fd + 1, &amp;fds, NULL, NULL, &amp;tv);
+                } while ((r == -1 &amp;&amp; (errno = EINTR)));
+                if (r == -1) {
+                        perror("select");
+                        return errno;
+                }
+
+                CLEAR(buf);
+                buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory = V4L2_MEMORY_MMAP;
+                xioctl(fd, VIDIOC_DQBUF, &amp;buf);
+
+                sprintf(out_name, "out%03d.ppm", i);
+                fout = fopen(out_name, "w");
+                if (!fout) {
+                        perror("Cannot open image");
+                        exit(EXIT_FAILURE);
+                }
+                fprintf(fout, "P6\n%d %d 255\n",
+                        fmt.fmt.pix.width, fmt.fmt.pix.height);
+                fwrite(buffers[buf.index].start, buf.bytesused, 1, fout);
+                fclose(fout);
+
+                xioctl(fd, VIDIOC_QBUF, &amp;buf);
+        }
+
+        type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        xioctl(fd, VIDIOC_STREAMOFF, &amp;type);
+        for (i = 0; i &lt; n_buffers; ++i)
+                v4l2_munmap(buffers[i].start, buffers[i].length);
+        v4l2_close(fd);
+
+        return 0;
+}
+</programlisting>