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<p>WSS capture example.</p>
<div class="fragment"><div class="line"><span class="comment">/*</span></div><div class="line"><span class="comment"> * libzvbi WSS capture example</span></div><div class="line"><span class="comment"> *</span></div><div class="line"><span class="comment"> * Copyright (C) 2005 Michael H. Schimek</span></div><div class="line"><span class="comment"> *</span></div><div class="line"><span class="comment"> * Redistribution and use in source and binary forms, with or without</span></div><div class="line"><span class="comment"> * modification, are permitted provided that the following conditions</span></div><div class="line"><span class="comment"> * are met:</span></div><div class="line"><span class="comment"> * 1. Redistributions of source code must retain the above copyright</span></div><div class="line"><span class="comment"> * notice, this list of conditions and the following disclaimer.</span></div><div class="line"><span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span></div><div class="line"><span class="comment"> * notice, this list of conditions and the following disclaimer in</span></div><div class="line"><span class="comment"> * the documentation and/or other materials provided with the</span></div><div class="line"><span class="comment"> * distribution.</span></div><div class="line"><span class="comment"> * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS</span></div><div class="line"><span class="comment"> * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT</span></div><div class="line"><span class="comment"> * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR</span></div><div class="line"><span class="comment"> * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT</span></div><div class="line"><span class="comment"> * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,</span></div><div class="line"><span class="comment"> * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT</span></div><div class="line"><span class="comment"> * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,</span></div><div class="line"><span class="comment"> * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY</span></div><div class="line"><span class="comment"> * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT</span></div><div class="line"><span class="comment"> * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE</span></div><div class="line"><span class="comment"> * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</span></div><div class="line"><span class="comment"> */</span></div><div class="line"></div><div class="line"><span class="comment">/* $Id: wss.c,v 1.11 2008/02/19 00:52:04 mschimek Exp $ */</span></div><div class="line"></div><div class="line"><span class="comment">/* This example shows how to extract Wide Screen Signalling data</span></div><div class="line"><span class="comment"> (EN 300 294) from video images. The signal is transmitted on the</span></div><div class="line"><span class="comment"> first half of PAL/SECAM scan line 23, which ITU-R BT.601 defines</span></div><div class="line"><span class="comment"> as the first line of a 576 line picture.</span></div><div class="line"><span class="comment"></span></div><div class="line"><span class="comment"> The author is not aware of any drivers which can capture a scan</span></div><div class="line"><span class="comment"> line as raw VBI and video data at the same time, and sliced VBI</span></div><div class="line"><span class="comment"> capturing is not supported yet by libzvbi. Note some drivers like</span></div><div class="line"><span class="comment"> the Linux saa7134 driver cannot capture line 23 at all.</span></div><div class="line"><span class="comment"></span></div><div class="line"><span class="comment"> gcc -o wss wss.c `pkg-config zvbi-0.2 --cflags --libs` */</span></div><div class="line"></div><div class="line"><span class="preprocessor">#ifdef HAVE_CONFIG_H</span></div><div class="line"><span class="preprocessor"># include "config.h"</span></div><div class="line"><span class="preprocessor">#endif</span></div><div class="line"></div><div class="line"><span class="preprocessor">#include <stdio.h></span></div><div class="line"><span class="preprocessor">#include <stdlib.h></span></div><div class="line"><span class="preprocessor">#include <string.h></span></div><div class="line"><span class="preprocessor">#include <assert.h></span></div><div class="line"></div><div class="line"><span class="preprocessor">#ifdef ENABLE_V4L2</span></div><div class="line"></div><div class="line"><span class="preprocessor">#include <fcntl.h></span> <span class="comment">/* low-level i/o */</span></div><div class="line"><span class="preprocessor">#include <unistd.h></span></div><div class="line"><span class="preprocessor">#include <errno.h></span></div><div class="line"><span class="preprocessor">#include <sys/stat.h></span></div><div class="line"><span class="preprocessor">#include <sys/types.h></span></div><div class="line"><span class="preprocessor">#include <sys/time.h></span></div><div class="line"><span class="preprocessor">#include <sys/mman.h></span></div><div class="line"><span class="preprocessor">#include <sys/ioctl.h></span></div><div class="line"></div><div class="line"><span class="preprocessor">#include <libzvbi.h></span></div><div class="line"></div><div class="line"><span class="preprocessor">#include <asm/types.h></span> <span class="comment">/* for videodev2.h */</span></div><div class="line"><span class="preprocessor">#include "videodev2k.h"</span></div><div class="line"></div><div class="line"><span class="preprocessor">#define CLEAR(x) memset (&(x), 0, sizeof (x))</span></div><div class="line"></div><div class="line"><span class="keyword">struct </span>buffer {</div><div class="line"> <span class="keywordtype">void</span> * start;</div><div class="line"> <span class="keywordtype">size_t</span> length;</div><div class="line">};</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">char</span> * dev_name = <span class="stringliteral">"/dev/video"</span>;</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> fd;</div><div class="line"><span class="keyword">static</span> <span class="keyword">struct </span>buffer * buffers;</div><div class="line"><span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> n_buffers;</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> quit;</div><div class="line"></div><div class="line"><span class="keyword">static</span> <a name="_a0"></a><a class="code" href="structvbi__raw__decoder.html">vbi_raw_decoder</a> rd;</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">errno_exit (<span class="keyword">const</span> <span class="keywordtype">char</span> * s)</div><div class="line">{</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s error %d, %s\n"</span>,</div><div class="line"> s, errno, strerror (errno));</div><div class="line"></div><div class="line"> exit (EXIT_FAILURE);</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span></div><div class="line">xioctl (<span class="keywordtype">int</span> fd,</div><div class="line"> <span class="keywordtype">int</span> request,</div><div class="line"> <span class="keywordtype">void</span> * p)</div><div class="line">{</div><div class="line"> <span class="keywordtype">int</span> r;</div><div class="line"></div><div class="line"> <span class="keywordflow">do</span> r = ioctl (fd, request, p);</div><div class="line"> <span class="keywordflow">while</span> (-1 == r && EINTR == errno);</div><div class="line"></div><div class="line"> <span class="keywordflow">return</span> r;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">decode_wss_625 (uint8_t * buf)</div><div class="line">{</div><div class="line"> <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">char</span> *formats [] = {</div><div class="line"> <span class="stringliteral">"Full format 4:3, 576 lines"</span>,</div><div class="line"> <span class="stringliteral">"Letterbox 14:9 centre, 504 lines"</span>,</div><div class="line"> <span class="stringliteral">"Letterbox 14:9 top, 504 lines"</span>,</div><div class="line"> <span class="stringliteral">"Letterbox 16:9 centre, 430 lines"</span>,</div><div class="line"> <span class="stringliteral">"Letterbox 16:9 top, 430 lines"</span>,</div><div class="line"> <span class="stringliteral">"Letterbox > 16:9 centre"</span>,</div><div class="line"> <span class="stringliteral">"Full format 14:9 centre, 576 lines"</span>,</div><div class="line"> <span class="stringliteral">"Anamorphic 16:9, 576 lines"</span></div><div class="line"> };</div><div class="line"> <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">char</span> *subtitles [] = {</div><div class="line"> <span class="stringliteral">"none"</span>,</div><div class="line"> <span class="stringliteral">"in active image area"</span>,</div><div class="line"> <span class="stringliteral">"out of active image area"</span>,</div><div class="line"> <span class="stringliteral">"<invalid>"</span></div><div class="line"> };</div><div class="line"> <span class="keywordtype">int</span> g1;</div><div class="line"> <span class="keywordtype">int</span> parity;</div><div class="line"></div><div class="line"> g1 = buf[0] & 15;</div><div class="line"></div><div class="line"> parity = g1;</div><div class="line"> parity ^= parity >> 2;</div><div class="line"> parity ^= parity >> 1;</div><div class="line"> g1 &= 7;</div><div class="line"></div><div class="line"> printf (<span class="stringliteral">"WSS PAL: "</span>);</div><div class="line"> <span class="keywordflow">if</span> (!(parity & 1))</div><div class="line"> printf (<span class="stringliteral">"<parity error> "</span>);</div><div class="line"> printf (<span class="stringliteral">"%s; %s mode; %s colour coding; %s helper; "</span></div><div class="line"> <span class="stringliteral">"reserved b7=%d; %s Teletext subtitles; "</span></div><div class="line"> <span class="stringliteral">"open subtitles: %s; %s surround sound; "</span></div><div class="line"> <span class="stringliteral">"copyright %s; copying %s\n"</span>,</div><div class="line"> formats[g1],</div><div class="line"> (buf[0] & 0x10) ? <span class="stringliteral">"film"</span> : <span class="stringliteral">"camera"</span>,</div><div class="line"> (buf[0] & 0x20) ? <span class="stringliteral">"MA/CP"</span> : <span class="stringliteral">"standard"</span>,</div><div class="line"> (buf[0] & 0x40) ? <span class="stringliteral">"modulated"</span> : <span class="stringliteral">"no"</span>,</div><div class="line"> !!(buf[0] & 0x80),</div><div class="line"> (buf[1] & 0x01) ? <span class="stringliteral">"have"</span> : <span class="stringliteral">"no"</span>,</div><div class="line"> subtitles[(buf[1] >> 1) & 3],</div><div class="line"> (buf[1] & 0x08) ? <span class="stringliteral">"have"</span> : <span class="stringliteral">"no"</span>,</div><div class="line"> (buf[1] & 0x10) ? <span class="stringliteral">"asserted"</span> : <span class="stringliteral">"unknown"</span>,</div><div class="line"> (buf[1] & 0x20) ? <span class="stringliteral">"restricted"</span> : <span class="stringliteral">"not restricted"</span>);</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">process_image (<span class="keyword">const</span> <span class="keywordtype">void</span> * p)</div><div class="line">{</div><div class="line"> <a name="_a1"></a><a class="code" href="structvbi__sliced.html">vbi_sliced</a> sliced[1];</div><div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> n_lines;</div><div class="line"></div><div class="line"> n_lines = <a name="a2"></a><a class="code" href="group__Rawdec.html#ga590834a98acc13c74c08b72de4fbfe80">vbi_raw_decode</a> (&rd, (uint8_t *) p, sliced);</div><div class="line"> <span class="keywordflow">if</span> (0 <span class="comment">/* test */</span>) {</div><div class="line"> <span class="comment">/* Error ignored. */</span></div><div class="line"> write (STDOUT_FILENO, p, rd.<a name="a3"></a><a class="code" href="structvbi__raw__decoder.html#a0610feb3dba297670cadb678d8370e80">bytes_per_line</a>);</div><div class="line"> } <span class="keywordflow">else</span> <span class="keywordflow">if</span> (n_lines > 0) {</div><div class="line"> assert (VBI_SLICED_WSS_625 == sliced[0].<span class="keywordtype">id</span>);</div><div class="line"> assert (1 == n_lines);</div><div class="line"> decode_wss_625 (sliced[0].data);</div><div class="line"> } <span class="keywordflow">else</span> {</div><div class="line"> fputc (<span class="charliteral">'.'</span>, stdout);</div><div class="line"> fflush (stdout);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">init_decoder (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> services;</div><div class="line"></div><div class="line"> <a name="a4"></a><a class="code" href="group__Rawdec.html#ga5bbc43c12196c9be0065ecc566906adb">vbi_raw_decoder_init</a> (&rd);</div><div class="line"></div><div class="line"> rd.<a name="a5"></a><a class="code" href="structvbi__raw__decoder.html#a7ff6b942e66eae2ca7a3b6bbfbbc550f">scanning</a> = 625;</div><div class="line"> rd.<a name="a6"></a><a class="code" href="structvbi__raw__decoder.html#a042431c6c0abab3eeecce4f9a014bd1d">sampling_format</a> = VBI_PIXFMT_YUYV;</div><div class="line"></div><div class="line"> <span class="comment">/* Should be calculated from VIDIOC_CROPCAP information.</span></div><div class="line"><span class="comment"> Common sampling rates are 14.75 MHz to get 768 PAL/SECAM</span></div><div class="line"><span class="comment"> square pixels per line, and 13.5 MHz according to ITU-R Rec.</span></div><div class="line"><span class="comment"> BT.601 with 720 pixels/line. Note BT.601 overscans the line:</span></div><div class="line"><span class="comment"> 13.5e6 / 720 > 14.75e6 / 768. Don't be fooled by a driver</span></div><div class="line"><span class="comment"> scaling 768 square pixels to 720. */</span></div><div class="line"> rd.<a name="a7"></a><a class="code" href="structvbi__raw__decoder.html#a72596d7bf3dd5f3fedf8ce51f25f6377">sampling_rate</a> = 768 * 14.75e6 / 768;</div><div class="line"></div><div class="line"> rd.<a class="code" href="structvbi__raw__decoder.html#a0610feb3dba297670cadb678d8370e80">bytes_per_line</a> = 768 * 2;</div><div class="line"></div><div class="line"> <span class="comment">/* Should be calculated from VIDIOC_CROPCAP information. */</span></div><div class="line"> rd.<a name="a8"></a><a class="code" href="structvbi__raw__decoder.html#aec686bff8271a5304417cdb2e84dd198">offset</a> = 0;</div><div class="line"></div><div class="line"> rd.<a name="a9"></a><a class="code" href="structvbi__raw__decoder.html#ab8a8df50593ebc6ab7d9f52f0cc8275d">start</a>[0] = 23;</div><div class="line"> rd.<a name="a10"></a><a class="code" href="structvbi__raw__decoder.html#ab77ddf5224b63d84d66c36daded1ab90">count</a>[0] = 1;</div><div class="line"></div><div class="line"> rd.<a class="code" href="structvbi__raw__decoder.html#ab8a8df50593ebc6ab7d9f52f0cc8275d">start</a>[1] = 0;</div><div class="line"> rd.<a class="code" href="structvbi__raw__decoder.html#ab77ddf5224b63d84d66c36daded1ab90">count</a>[1] = 0;</div><div class="line"></div><div class="line"> rd.<a name="a11"></a><a class="code" href="structvbi__raw__decoder.html#ab21be06e2fb0141314311d820c51b35f">interlaced</a> = FALSE; <span class="comment">/* just one line */</span></div><div class="line"> rd.<a name="a12"></a><a class="code" href="structvbi__raw__decoder.html#adbeef46d32445684cdf52c4cfbe8f3ac">synchronous</a> = TRUE;</div><div class="line"></div><div class="line"> services = <a name="a13"></a><a class="code" href="group__Rawdec.html#ga18c46d4a4885261c45e32e8eb509d1b9">vbi_raw_decoder_add_services</a> (&rd,</div><div class="line"> VBI_SLICED_WSS_625,</div><div class="line"> <span class="comment">/* strict */</span> 2);</div><div class="line"> <span class="keywordflow">if</span> (0 == services) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Cannot decode WSS\n"</span>);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">mainloop (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> quit = 0;</div><div class="line"></div><div class="line"> <span class="keywordflow">while</span> (!quit) {</div><div class="line"> <span class="keyword">struct </span>v4l2_buffer buf;</div><div class="line"></div><div class="line"> <span class="keywordflow">for</span> (;;) {</div><div class="line"> fd_set fds;</div><div class="line"> <span class="keyword">struct </span>timeval tv;</div><div class="line"> <span class="keywordtype">int</span> r;</div><div class="line"></div><div class="line"> FD_ZERO (&fds);</div><div class="line"> FD_SET (fd, &fds);</div><div class="line"></div><div class="line"> tv.tv_sec = 2;</div><div class="line"> tv.tv_usec = 0;</div><div class="line"></div><div class="line"> r = select (fd + 1, &fds, NULL, NULL, &tv);</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == r) {</div><div class="line"> <span class="keywordflow">if</span> (EINTR == errno) {</div><div class="line"> <span class="comment">/* XXX should subtract the elapsed</span></div><div class="line"><span class="comment"> time from timeout here. */</span></div><div class="line"> <span class="keywordflow">continue</span>;</div><div class="line"> }</div><div class="line"></div><div class="line"> errno_exit (<span class="stringliteral">"select"</span>);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (0 == r) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"select timeout\n"</span>);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">break</span>;</div><div class="line"> }</div><div class="line"></div><div class="line"> CLEAR (buf);</div><div class="line"></div><div class="line"> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"> buf.memory = V4L2_MEMORY_MMAP;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_DQBUF, &buf)) {</div><div class="line"> <span class="keywordflow">if</span> (EAGAIN == errno)</div><div class="line"> <span class="keywordflow">continue</span>;</div><div class="line"></div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_DQBUF"</span>);</div><div class="line"> }</div><div class="line"></div><div class="line"> assert (buf.index < n_buffers);</div><div class="line"></div><div class="line"> process_image (buffers[buf.index].start);</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_QBUF, &buf))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_QBUF"</span>);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">start_capturing (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;</div><div class="line"> <span class="keyword">enum</span> v4l2_buf_type type;</div><div class="line"></div><div class="line"> <span class="keywordflow">for</span> (i = 0; i < n_buffers; ++i) {</div><div class="line"> <span class="keyword">struct </span>v4l2_buffer buf;</div><div class="line"></div><div class="line"> CLEAR (buf);</div><div class="line"></div><div class="line"> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"> buf.memory = V4L2_MEMORY_MMAP;</div><div class="line"> buf.index = i;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_QBUF, &buf))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_QBUF"</span>);</div><div class="line"> }</div><div class="line"></div><div class="line"> type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_STREAMON, &type))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_STREAMON"</span>);</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">init_device (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> <span class="keyword">struct </span>v4l2_capability cap;</div><div class="line"> v4l2_std_id std_id;</div><div class="line"> <span class="keyword">struct </span>v4l2_format fmt;</div><div class="line"> <span class="keyword">struct </span>v4l2_requestbuffers req;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_QUERYCAP, &cap)) {</div><div class="line"> <span class="keywordflow">if</span> (EINVAL == errno) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s is no V4L2 device\n"</span>,</div><div class="line"> dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> } <span class="keywordflow">else</span> {</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_QUERYCAP"</span>);</div><div class="line"> }</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s is no video capture device\n"</span>,</div><div class="line"> dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (!(cap.capabilities & V4L2_CAP_STREAMING)) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s does not support streaming I/O\n"</span>,</div><div class="line"> dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> std_id = V4L2_STD_PAL;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_S_STD, &std_id))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_S_STD"</span>);</div><div class="line"></div><div class="line"> CLEAR (fmt);</div><div class="line"></div><div class="line"> <span class="comment">/* We need the top field without vertical scaling,</span></div><div class="line"><span class="comment"> width must be at least 320 pixels. */</span></div><div class="line"></div><div class="line"> fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"> fmt.fmt.pix.width = 768; </div><div class="line"> fmt.fmt.pix.height = 576;</div><div class="line"> fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;</div><div class="line"> fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_S_FMT, &fmt))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_S_FMT"</span>);</div><div class="line"></div><div class="line"> <span class="comment">/* XXX the driver may adjust width and height, some</span></div><div class="line"><span class="comment"> even change the pixelformat, that should be checked here. */</span></div><div class="line"></div><div class="line"> CLEAR (req);</div><div class="line"></div><div class="line"> req.count = 4;</div><div class="line"> req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"> req.memory = V4L2_MEMORY_MMAP;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_REQBUFS, &req)) {</div><div class="line"> <span class="keywordflow">if</span> (EINVAL == errno) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s does not support "</span></div><div class="line"> <span class="stringliteral">"memory mapping\n"</span>, dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> } <span class="keywordflow">else</span> {</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_REQBUFS"</span>);</div><div class="line"> }</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (req.count < 2) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Insufficient buffer memory on %s\n"</span>,</div><div class="line"> dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> buffers = calloc (req.count, sizeof (*buffers));</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (!buffers) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Out of memory\n"</span>);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">for</span> (n_buffers = 0; n_buffers < req.count; ++n_buffers) {</div><div class="line"> <span class="keyword">struct </span>v4l2_buffer buf;</div><div class="line"></div><div class="line"> CLEAR (buf);</div><div class="line"></div><div class="line"> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;</div><div class="line"> buf.memory = V4L2_MEMORY_MMAP;</div><div class="line"> buf.index = n_buffers;</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == xioctl (fd, VIDIOC_QUERYBUF, &buf))</div><div class="line"> errno_exit (<span class="stringliteral">"VIDIOC_QUERYBUF"</span>);</div><div class="line"></div><div class="line"> buffers[n_buffers].length = buf.length;</div><div class="line"> buffers[n_buffers].start =</div><div class="line"> mmap (NULL <span class="comment">/* start anywhere */</span>,</div><div class="line"> buf.length,</div><div class="line"> PROT_READ | PROT_WRITE <span class="comment">/* required */</span>,</div><div class="line"> MAP_SHARED <span class="comment">/* recommended */</span>,</div><div class="line"> fd, buf.m.offset);</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (MAP_FAILED == buffers[n_buffers].start)</div><div class="line"> errno_exit (<span class="stringliteral">"mmap"</span>);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span></div><div class="line">open_device (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> <span class="keyword">struct </span>stat st; </div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == stat (dev_name, &st)) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Cannot identify '%s': %d, %s\n"</span>,</div><div class="line"> dev_name, errno, strerror (errno));</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (!S_ISCHR (st.st_mode)) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"%s is no device\n"</span>, dev_name);</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line"></div><div class="line"> fd = open (dev_name, O_RDWR | O_NONBLOCK, 0);</div><div class="line"></div><div class="line"> <span class="keywordflow">if</span> (-1 == fd) {</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Cannot open '%s': %d, %s\n"</span>,</div><div class="line"> dev_name, errno, strerror (errno));</div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> }</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keywordtype">int</span></div><div class="line">main (<span class="keywordtype">void</span>)</div><div class="line">{</div><div class="line"> <span class="comment">/* Helps debugging. */</span></div><div class="line"> <a name="a14"></a><a class="code" href="group__Basic.html#ga594dbe49c85f00a11c3586a131203b61">vbi_set_log_fn</a> (<span class="comment">/* mask: log everything */</span> -1,</div><div class="line"> <a name="a15"></a><a class="code" href="group__Basic.html#ga892c64da1c60919512f0c4db6641a708">vbi_log_on_stderr</a>,</div><div class="line"> <span class="comment">/* user_data */</span> NULL);</div><div class="line"></div><div class="line"> open_device ();</div><div class="line"></div><div class="line"> init_device ();</div><div class="line"></div><div class="line"> init_decoder ();</div><div class="line"></div><div class="line"> start_capturing ();</div><div class="line"></div><div class="line"> mainloop ();</div><div class="line"></div><div class="line"> exit (EXIT_SUCCESS);</div><div class="line"></div><div class="line"> <span class="keywordflow">return</span> 0;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="preprocessor">#else </span><span class="comment">/* !ENABLE_V4L2 */</span><span class="preprocessor"></span></div><div class="line"></div><div class="line"><span class="keywordtype">int</span></div><div class="line">main (<span class="keywordtype">int</span> argc,</div><div class="line"> <span class="keywordtype">char</span> ** argv)</div><div class="line">{</div><div class="line"> fprintf (stderr, <span class="stringliteral">"Sorry, V4L2 only. Patches welcome.\n"</span>);</div><div class="line"></div><div class="line"> exit (EXIT_FAILURE);</div><div class="line"> </div><div class="line"> <span class="keywordflow">return</span> 0;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="preprocessor">#endif </span><span class="comment">/* !ENABLE_V4L2 */</span><span class="preprocessor"></span></div></div><!-- fragment --> </div><!-- contents -->
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