diff -r 6220548f4843 -r ccae4c3150d2 v4l2-spec/controls.sgml
--- a/v4l2-spec/controls.sgml	Wed May 27 11:56:46 2009 +0300
+++ b/v4l2-spec/controls.sgml	Wed May 13 13:10:24 2009 +0300
@@ -458,6 +458,12 @@
       <para>Unfortunately, the original control API lacked some
 features needed for these new uses and so it was extended into the
 (not terribly originally named) extended control API.</para>
+
+      <para>Even though the MPEG encoding API was the first effort
+to use the Extended Control API, nowadays there are also other classes
+of Extended Controls, such as Camera Controls and FM Transmitter Controls.
+The Extended Controls API as well as all Extended Controls classes are
+described in the following text.</para>
     </section>
 
     <section>
@@ -1816,6 +1822,200 @@
       </tgroup>
     </table>
   </section>
+
+    <section id="fmtx-controls">
+      <title>FM Transmitter Control Reference</title>
+
+      <para>The FM Transmitter (FMTX) class includes controls for common features of
+FM transmissions capable devices. Currently this class include parameters for audio
+compression, pilot tone generation, audio deviation limiter, RDS transmission and
+tuning power features.</para>
+
+      <table pgwide="1" frame="none" id="fmtx-control-id">
+      <title>FMTX Control IDs</title>
+
+      <tgroup cols="4">
+	<colspec colname="c1" colwidth="1*">
+	<colspec colname="c2" colwidth="6*">
+	<colspec colname="c3" colwidth="2*">
+	<colspec colname="c4" colwidth="6*">
+	<spanspec namest="c1" nameend="c2" spanname="id">
+	<spanspec namest="c2" nameend="c4" spanname="descr">
+	<thead>
+	  <row>
+	    <entry spanname="id" align="left">ID</entry>
+	    <entry align="left">Type</entry>
+	  </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
+	  </row>
+	</thead>
+	<tbody valign="top">
+	  <row><entry></entry></row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_FMTX_CLASS</constant>&nbsp;</entry>
+	    <entry>class</entry>
+	  </row><row><entry spanname="descr">The FMTX class
+descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
+description of this control class.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_RDS_ENABLED</constant>&nbsp;</entry>
+	    <entry>boolean</entry>
+	  </row>
+	  <row><entry spanname="descr">Enables or disables the RDS transmission feature.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_RDS_PI</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the RDS Programme Identification field
+for transmission.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_RDS_PTY</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the RDS Programme Type field for transmission.
+This coding of up to 31 pre-defined programme types.</entry>
+	  </row>
+<!--
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_RDS_PS_NAME</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_RDS_RADIO_TEXT</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">.</entry>
+	  </row>
+-->
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant>&nbsp;</entry>
+	    <entry>boolean</entry>
+	  </row>
+	  <row><entry spanname="descr">Enables or disables the audio deviation limiter feature.
+The limiter is useful when trying to maximize the audio volume, minimize receiver-generated
+distortion and prevent overmodulation.
+</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_RELEASE_TIME</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the audio deviation limiter feature release time.
+The unit, step and range are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Configures audio frequency deviation level in Hz.
+The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ENABLED</constant>&nbsp;</entry>
+	    <entry>boolean</entry>
+	  </row>
+	  <row><entry spanname="descr">Enables or disables the audio compression feature.
+This feature amplifies signals below the threshold by a fixed gain and compresses audio
+signals above the threshold by the ratio of Threshold/(Gain + Threshold).</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_GAIN</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the gain for audio compression feature. It is
+a dB value. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_THRESHOLD</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the threshold level for audio compression freature.
+It is a dB value. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the attack time for audio compression feature.
+It is a useconds value. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the release time for audio compression feature.
+It is a useconds value. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_ENABLED</constant>&nbsp;</entry>
+	    <entry>boolean</entry>
+	  </row>
+	  <row><entry spanname="descr">Enables or disables the pilot tone generation feature.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_DEVIATION</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Configures pilot tone frequency deviation level. Unit is
+in Hz. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_PILOT_TONE_FREQUENCY</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Configures pilot tone frequency value. Unit is
+in Hz. The range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_PREEMPHASIS</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Configures the pre-emphasis value for broadcasting.
+A pre-emphasis filter is applied to the broadcast to accentuate the high audio frequencies.
+Depending on the region, a time constant of either 50 or 75 useconds is used. Possible values
+are:</entry>
+	</row><row>
+	<entrytbl spanname="descr" cols="2">
+		  <tbody valign="top">
+		    <row>
+		      <entry><constant>V4L2_FMTX_PREEMPHASIS_DISABLED</constant>&nbsp;</entry>
+		      <entry>No pre-emphasis is applied.</entry>
+		    </row>
+		    <row>
+		      <entry><constant>V4L2_FMTX_PREEMPHASIS_50_uS</constant>&nbsp;</entry>
+		      <entry>A pre-emphasis of 50 uS is used.</entry>
+		    </row>
+		    <row>
+		      <entry><constant>V4L2_FMTX_PREEMPHASIS_75_uS</constant>&nbsp;</entry>
+		      <entry>A pre-emphasis of 75 uS is used.</entry>
+		    </row>
+		  </tbody>
+		</entrytbl>
+
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_TUNE_POWER_LEVEL</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">Sets the output power level for signal transmission.
+Unit is in dBuV. Range and step are driver-specific.</entry>
+	  </row>
+	  <row>
+	    <entry spanname="id"><constant>V4L2_CID_TUNE_ANTENNA_CAPACITOR</constant>&nbsp;</entry>
+	    <entry>integer</entry>
+	  </row>
+	  <row><entry spanname="descr">This selects the value of antenna tuning capacitor
+manually or automatically if set to zero. Unit, range and step are driver-specific.</entry>
+	  </row>
+	  <row><entry></entry></row>
+	</tbody>
+      </tgroup>
+      </table>
+    </section>
 </section>
 
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