docs/plugins/html/gst-plugins-bad-plugins-videodetect.html

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  24 <a href="#gst-plugins-bad-plugins-videodetect.synopsis" class="shortcut">Top</a>
  25                    |
  26                   <a href="#gst-plugins-bad-plugins-videodetect.description" class="shortcut">Description</a>
  27                    |
  28                   <a href="#gst-plugins-bad-plugins-videodetect.object-hierarchy" class="shortcut">Object Hierarchy</a>
  29                    |
  30                   <a href="#gst-plugins-bad-plugins-videodetect.properties" class="shortcut">Properties</a>
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  33 <div class="refentry">
  34 <a name="gst-plugins-bad-plugins-videodetect"></a><div class="titlepage"></div>
  35 <div class="refnamediv"><table width="100%"><tr>
  36 <td valign="top">
  37 <h2><span class="refentrytitle"><a name="gst-plugins-bad-plugins-videodetect.top_of_page"></a>videodetect</span></h2>
  38 <p>videodetect — Detect patterns in a video signal</p>
  39 </td>
  40 <td valign="top" align="right"></td>
  41 </tr></table></div>
  42 <div class="refsynopsisdiv">
  43 <a name="gst-plugins-bad-plugins-videodetect.synopsis"></a><h2>Synopsis</h2>
  44 <a name="GstVideoDetect"></a><pre class="synopsis">struct              <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect-struct" title="struct GstVideoDetect">GstVideoDetect</a>;
  45 </pre>
  46 </div>
  47 <div class="refsect1">
  48 <a name="gst-plugins-bad-plugins-videodetect.object-hierarchy"></a><h2>Object Hierarchy</h2>
  49 <pre class="synopsis">
  50   <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
  51    +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a>
  52          +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a>
  53                +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseTransform.html">GstBaseTransform</a>
  54                      +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstvideofilter.html#GstVideoFilter">GstVideoFilter</a>
  55                            +----GstVideoDetect
  56 </pre>
  57 </div>
  58 <div class="refsect1">
  59 <a name="gst-plugins-bad-plugins-videodetect.properties"></a><h2>Properties</h2>
  60 <pre class="synopsis">
  61   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--message" title='The "message" property'>message</a>"                  <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write / Construct
  62   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-count" title='The "pattern-count" property'>pattern-count</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  63   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-data-count" title='The "pattern-data-count" property'>pattern-data-count</a>"       <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  64   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-height" title='The "pattern-height" property'>pattern-height</a>"           <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  65   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-sensitivity" title='The "pattern-sensitivity" property'>pattern-sensitivity</a>"      <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write / Construct
  66   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-width" title='The "pattern-width" property'>pattern-width</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  67   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--bottom-offset" title='The "bottom-offset" property'>bottom-offset</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  68   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--left-offset" title='The "left-offset" property'>left-offset</a>"              <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct
  69   "<a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-center" title='The "pattern-center" property'>pattern-center</a>"           <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write / Construct
  70 </pre>
  71 </div>
  72 <div class="refsect1">
  73 <a name="gst-plugins-bad-plugins-videodetect.description"></a><h2>Description</h2>
  74 <p>
  75 This plugin detects <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-count" title='The "pattern-count" property'><span class="type">"pattern-count"</span></a> squares in the bottom left
  76 corner of the video frames. The squares have a width and height of
  77 respectively <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-width" title='The "pattern-width" property'><span class="type">"pattern-width"</span></a> and <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-height" title='The "pattern-height" property'><span class="type">"pattern-height"</span></a>.
  78 Even squares must be black and odd squares must be white.
  79 </p>
  80 <p>
  81 When the pattern has been found, <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--pattern-data-count" title='The "pattern-data-count" property'><span class="type">"pattern-data-count"</span></a> squares
  82 after the pattern squares are read as a bitarray. White squares represent a 1
  83 bit and black squares a 0 bit. The bitarray will will included in the element
  84 message that is posted (see below).
  85 </p>
  86 <p>
  87 After the pattern has been found and the data pattern has been read, an
  88 element message called <code class="classname">"GstVideoDetect"</code> will
  89 be posted on the bus. If the pattern is no longer found in the frame, the
  90 same element message is posted with the have-pattern field set to <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><span class="type">FALSE</span></a>.
  91 The message is only posted if the <a class="link" href="gst-plugins-bad-plugins-videodetect.html#GstVideoDetect--message" title='The "message" property'><span class="type">"message"</span></a> property is <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a>.
  92 </p>
  93 <p>
  94 The message's structure contains these fields:
  95 </p>
  96 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
  97 <li class="listitem"><p>
  98   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>
  99   <code class="classname">"have-pattern"</code>:
 100   if the pattern was found. This field will be set to <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a> for as long as
 101   the pattern was found in the frame and set to FALSE for the first frame
 102   that does not contain the pattern anymore.
 103   </p></li>
 104 <li class="listitem"><p>
 105   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 106   <code class="classname">"timestamp"</code>:
 107   the timestamp of the buffer that triggered the message.
 108   </p></li>
 109 <li class="listitem"><p>
 110   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 111   <code class="classname">"stream-time"</code>:
 112   the stream time of the buffer.
 113   </p></li>
 114 <li class="listitem"><p>
 115   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 116   <code class="classname">"running-time"</code>:
 117   the running_time of the buffer.
 118   </p></li>
 119 <li class="listitem"><p>
 120   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 121   <code class="classname">"duration"</code>:
 122   the duration of the buffer.
 123   </p></li>
 124 <li class="listitem"><p>
 125   <span class="type">guint64</span>
 126   <code class="classname">"data-uint64"</code>:
 127   the data-pattern found after the pattern or 0 when have-signal is <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><span class="type">FALSE</span></a>.
 128   </p></li>
 129 <li class="listitem"><p>
 130   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a>
 131   <code class="classname">"data"</code>:
 132   the data-pattern found after the pattern or 0 when have-signal is <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><span class="type">FALSE</span></a>.
 133   </p></li>
 134 </ul></div>
 135 <p>
 136 </p>
 137 <p>
 138 </p>
 139 <div class="refsect2">
 140 <a name="idp23525664"></a><h3>Example launch line</h3>
 141 <div class="informalexample">
 142   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 143     <tbody>
 144       <tr>
 145         <td class="listing_lines" align="right"><pre>1</pre></td>
 146         <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch videotestsrc <span class="gtkdoc opt">!</span> videodetect <span class="gtkdoc opt">!</span> ffmpegcolorspace <span class="gtkdoc opt">!</span> ximagesink</pre></td>
 147       </tr>
 148     </tbody>
 149   </table>
 150 </div>
 151
 152 </div>
 153 <p>
 154 </p>
 155 <p>
 156 Last reviewed on 2007-05-30 (0.10.5)
 157 </p>
 158 <div class="refsynopsisdiv">
 159 <h2>Synopsis</h2>
 160 <div class="refsect2">
 161 <a name="idp23528768"></a><h3>Element Information</h3>
 162 <div class="variablelist"><table border="0">
 163 <col align="left" valign="top">
 164 <tbody>
 165 <tr>
 166 <td><p><span class="term">plugin</span></p></td>
 167 <td>
 168             <a class="link" href="gst-plugins-bad-plugins-plugin-videosignal.html#plugin-videosignal">videosignal</a>
 169           </td>
 170 </tr>
 171 <tr>
 172 <td><p><span class="term">author</span></p></td>
 173 <td>Wim Taymans &lt;wim@fluendo.com&gt;</td>
 174 </tr>
 175 <tr>
 176 <td><p><span class="term">class</span></p></td>
 177 <td>Filter/Effect/Video</td>
 178 </tr>
 179 </tbody>
 180 </table></div>
 181 </div>
 182 <hr>
 183 <div class="refsect2">
 184 <a name="idp23536224"></a><h3>Element Pads</h3>
 185 <div class="variablelist"><table border="0">
 186 <col align="left" valign="top">
 187 <tbody>
 188 <tr>
 189 <td><p><span class="term">name</span></p></td>
 190 <td>sink</td>
 191 </tr>
 192 <tr>
 193 <td><p><span class="term">direction</span></p></td>
 194 <td>sink</td>
 195 </tr>
 196 <tr>
 197 <td><p><span class="term">presence</span></p></td>
 198 <td>always</td>
 199 </tr>
 200 <tr>
 201 <td><p><span class="term">details</span></p></td>
 202 <td>video/x-raw-yuv, format=(fourcc){ I420, YV12, Y41B, Y42B, Y444, YUY2, UYVY, AYUV, YVYU }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]</td>
 203 </tr>
 204 </tbody>
 205 </table></div>
 206 <div class="variablelist"><table border="0">
 207 <col align="left" valign="top">
 208 <tbody>
 209 <tr>
 210 <td><p><span class="term">name</span></p></td>
 211 <td>src</td>
 212 </tr>
 213 <tr>
 214 <td><p><span class="term">direction</span></p></td>
 215 <td>source</td>
 216 </tr>
 217 <tr>
 218 <td><p><span class="term">presence</span></p></td>
 219 <td>always</td>
 220 </tr>
 221 <tr>
 222 <td><p><span class="term">details</span></p></td>
 223 <td>video/x-raw-yuv, format=(fourcc){ I420, YV12, Y41B, Y42B, Y444, YUY2, UYVY, AYUV, YVYU }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]</td>
 224 </tr>
 225 </tbody>
 226 </table></div>
 227 </div>
 228 </div>
 229 <p>
 230 </p>
 231 </div>
 232 <div class="refsect1">
 233 <a name="gst-plugins-bad-plugins-videodetect.details"></a><h2>Details</h2>
 234 <div class="refsect2">
 235 <a name="GstVideoDetect-struct"></a><h3>struct GstVideoDetect</h3>
 236 <pre class="programlisting">struct GstVideoDetect;</pre>
 237 <p>
 238 Opaque datastructure.
 239 </p>
 240 </div>
 241 </div>
 242 <div class="refsect1">
 243 <a name="gst-plugins-bad-plugins-videodetect.property-details"></a><h2>Property Details</h2>
 244 <div class="refsect2">
 245 <a name="GstVideoDetect--message"></a><h3>The <code class="literal">"message"</code> property</h3>
 246 <pre class="programlisting">  "message"                  <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write / Construct</pre>
 247 <p>Post statics messages.</p>
 248 <p>Default value: TRUE</p>
 249 </div>
 250 <hr>
 251 <div class="refsect2">
 252 <a name="GstVideoDetect--pattern-count"></a><h3>The <code class="literal">"pattern-count"</code> property</h3>
 253 <pre class="programlisting">  "pattern-count"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 254 <p>The number of pattern markers.</p>
 255 <p>Allowed values: &gt;= 0</p>
 256 <p>Default value: 4</p>
 257 </div>
 258 <hr>
 259 <div class="refsect2">
 260 <a name="GstVideoDetect--pattern-data-count"></a><h3>The <code class="literal">"pattern-data-count"</code> property</h3>
 261 <pre class="programlisting">  "pattern-data-count"       <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 262 <p>The number of extra data pattern markers.</p>
 263 <p>Allowed values: &gt;= 0</p>
 264 <p>Default value: 5</p>
 265 </div>
 266 <hr>
 267 <div class="refsect2">
 268 <a name="GstVideoDetect--pattern-height"></a><h3>The <code class="literal">"pattern-height"</code> property</h3>
 269 <pre class="programlisting">  "pattern-height"           <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 270 <p>The height of the pattern markers.</p>
 271 <p>Allowed values: &gt;= 1</p>
 272 <p>Default value: 16</p>
 273 </div>
 274 <hr>
 275 <div class="refsect2">
 276 <a name="GstVideoDetect--pattern-sensitivity"></a><h3>The <code class="literal">"pattern-sensitivity"</code> property</h3>
 277 <pre class="programlisting">  "pattern-sensitivity"      <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write / Construct</pre>
 278 <p>The sensitivity around the center for detecting the markers (0.0 = lowest, 1.0 highest).</p>
 279 <p>Allowed values: [0,1]</p>
 280 <p>Default value: 0.3</p>
 281 </div>
 282 <hr>
 283 <div class="refsect2">
 284 <a name="GstVideoDetect--pattern-width"></a><h3>The <code class="literal">"pattern-width"</code> property</h3>
 285 <pre class="programlisting">  "pattern-width"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 286 <p>The width of the pattern markers.</p>
 287 <p>Allowed values: &gt;= 1</p>
 288 <p>Default value: 4</p>
 289 </div>
 290 <hr>
 291 <div class="refsect2">
 292 <a name="GstVideoDetect--bottom-offset"></a><h3>The <code class="literal">"bottom-offset"</code> property</h3>
 293 <pre class="programlisting">  "bottom-offset"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 294 <p>The offset from the bottom border where the pattern starts.</p>
 295 <p>Allowed values: &gt;= 0</p>
 296 <p>Default value: 0</p>
 297 </div>
 298 <hr>
 299 <div class="refsect2">
 300 <a name="GstVideoDetect--left-offset"></a><h3>The <code class="literal">"left-offset"</code> property</h3>
 301 <pre class="programlisting">  "left-offset"              <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write / Construct</pre>
 302 <p>The offset from the left border where the pattern starts.</p>
 303 <p>Allowed values: &gt;= 0</p>
 304 <p>Default value: 0</p>
 305 </div>
 306 <hr>
 307 <div class="refsect2">
 308 <a name="GstVideoDetect--pattern-center"></a><h3>The <code class="literal">"pattern-center"</code> property</h3>
 309 <pre class="programlisting">  "pattern-center"           <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write / Construct</pre>
 310 <p>The center of the black/white separation (0.0 = lowest, 1.0 highest).</p>
 311 <p>Allowed values: [0,1]</p>
 312 <p>Default value: 0.5</p>
 313 </div>
 314 </div>
 315 <div class="refsect1">
 316 <a name="gst-plugins-bad-plugins-videodetect.see-also"></a><h2>See Also</h2>
 317 <a class="link" href="gst-plugins-bad-plugins-videomark.html#GstVideoMark"><span class="type">GstVideoMark</span></a>
 318 </div>
 319 </div>
 320 <div class="footer">
 321 <hr>
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