This single patch adds documentation description for FM Modulator (FM_TX)
Extended Control Class and its Control IDs. The text was added under
"Extended Controls" section.
Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxxxxx>
---
v4l2-spec/Makefile | 1 +
v4l2-spec/controls.sgml | 200 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 201 insertions(+), 0 deletions(-)
diff --git a/v4l2-spec/Makefile b/v4l2-spec/Makefile
index 7a19924..6b46433 100644
--- a/v4l2-spec/Makefile
+++ b/v4l2-spec/Makefile
@@ -242,6 +242,7 @@ ENUMS = \
v4l2_power_line_frequency \
v4l2_priority \
v4l2_tuner_type \
+ v4l2_preemphasis \
STRUCTS = \
v4l2_audio \
diff --git a/v4l2-spec/controls.sgml b/v4l2-spec/controls.sgml
index 477a970..205a7a6 100644
--- a/v4l2-spec/controls.sgml
+++ b/v4l2-spec/controls.sgml
@@ -458,6 +458,12 @@ video is actually encoded into that format.</para>
<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 @@ control must support read access and may support write access.</entry>
</tgroup>
</table>
</section>
+
+ <section id="fm-tx-controls">
+ <title>FM Transmitter Control Reference</title>
+
+ <para>The FM Transmitter (FM_TX) 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="fm-tx-control-id">
+ <title>FM_TX 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_FM_TX_CLASS</constant> </entry>
+ <entry>class</entry>
+ </row><row><entry spanname="descr">The FM_TX 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_TX_PI</constant> </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_TX_PTY</constant> </entry>
+ <entry>integer</entry>
+ </row>
+ <row><entry spanname="descr">Sets the RDS Programme Type field for transmission.
+This encodes up to 31 pre-defined programme types.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_RDS_TX_PS_NAME</constant> </entry>
+ <entry>string</entry>
+ </row>
+ <row><entry spanname="descr">Sets the Programme Service name (PS_NAME) for transmission.
+It is intended for static display on a receiver. It is the primary aid to listeners in programme service
+identification and selection. The use of PS to transmit text other than a single eight character name is not permitted.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_RDS_TX_RADIO_TEXT</constant> </entry>
+ <entry>string</entry>
+ </row>
+ <row><entry spanname="descr">Sets the Radio Text info for transmission. It is a textual description of
+what is being broadcasted. RDS Radio Text can be applied when broadcaster wishes to transmit longer PS names,
+programme-related information or any other text. In these cases, RadioText should be used in addition to
+<constant>V4L2_CID_RDS_TX_PS_NAME</constant>.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_ENABLED</constant> </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> </entry>
+ <entry>integer</entry>
+ </row>
+ <row><entry spanname="descr">Sets the audio deviation limiter feature release time.
+Unit is in useconds. Step and range are driver-specific.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_AUDIO_LIMITER_DEVIATION</constant> </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> </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> </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> </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> </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> </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> </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> </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> </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_FM_TX_PREEMPHASIS</constant> </entry>
+ <entry>integer</entry>
+ </row>
+ <row id="v4l2-preemphasis"><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. The enum v4l2_preemphasis
+defines possible values for pre-emphasis. Here they are:</entry>
+ </row><row>
+ <entrytbl spanname="descr" cols="2">
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_PREEMPHASIS_DISABLED</constant> </entry>
+ <entry>No pre-emphasis is applied.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_PREEMPHASIS_50_uS</constant> </entry>
+ <entry>A pre-emphasis of 50 uS is used.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_PREEMPHASIS_75_uS</constant> </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> </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> </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>
+
+<para>For more details about RDS specification, refer to
+<xref linkend="en50067"> document, from CENELEC.</para>
+ </section>
</section>
<!--
--
1.6.2.GIT
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