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.valen...@nokia.com>
---
v4l2-spec/Makefile | 1 +
v4l2-spec/controls.sgml | 210 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 211 insertions(+), 0 deletions(-)
diff --git a/v4l2-spec/Makefile b/v4l2-spec/Makefile
index 4f11745..7a8d161 100644
--- a/v4l2-spec/Makefile
+++ b/v4l2-spec/Makefile
@@ -243,6 +243,7 @@ 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 8e0e024..791df4d 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>
@@ -1815,6 +1821,210 @@ 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 includes 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_DEVIATION</constant> </entry>
+ <entry>integer</entry>
+ </row>
+ <row><entry spanname="descr">Configures RDS signal frequency
deviation level in Hz.
+The range and step are driver-specific.</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. In Annex E of <xref linkend="en50067">, the RDS specification,
+there is a full description of the correct character encoding for Programme
Service name strings.</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>. The encoding for Radio Text
strings is also fully described
+in Annex E of <xref linkend="en50067">.</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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