On Friday 12 June 2009 19:30:36 Eduardo Valentin wrote:
> 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 <[email protected]>
> ---
> v4l2-spec/Makefile | 1 +
> v4l2-spec/biblio.sgml | 10 +++
> v4l2-spec/controls.sgml | 205
> +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 216 insertions(+), 0 deletions(-)
>
> diff --git a/v4l2-spec/Makefile b/v4l2-spec/Makefile
> index 7a19924..bfe2965 100644
> --- a/v4l2-spec/Makefile
> +++ b/v4l2-spec/Makefile
> @@ -242,6 +242,7 @@ ENUMS = \
> v4l2_power_line_frequency \
> v4l2_priority \
> v4l2_tuner_type \
> + v4l2_fm_tx_preemphasis \
>
> STRUCTS = \
> v4l2_audio \
> diff --git a/v4l2-spec/biblio.sgml b/v4l2-spec/biblio.sgml
> index b013ece..0921849 100644
> --- a/v4l2-spec/biblio.sgml
> +++ b/v4l2-spec/biblio.sgml
> @@ -11,6 +11,16 @@
> url="http://www.eia.org";>http://www.eia.org</ulink>)</corpauthor>
> Service"</title>
> </biblioentry>
>
> + <biblioentry id="en50067">
> + <abbrev>EN 50067</abbrev>
> + <authorgroup>
> + <corpauthor>CENELEC European Committee for Electrotechnical
> Standardization
> +(<ulink
> url="http://www.cenelec.eu";>http://www.cenelec.eu</ulink>)</corpauthor>
> + </authorgroup>
> + <title>EN 50067 "Specification of the radio data system (RDS) for
> +VHF/FM sound broadcasting in the frequency range from 87,5 to 108,0
> MHz"</title>
> + </biblioentry>
> +
> <biblioentry id="en300294">
> <abbrev>EN 300 294</abbrev>
> <authorgroup>
> diff --git a/v4l2-spec/controls.sgml b/v4l2-spec/controls.sgml
> index 477a970..0bb6f00 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 +1822,205 @@ 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_ENABLED</constant> </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> </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> </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>
coding -> encodes
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_RDS_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_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. If broadcaster wishes to transmit longer PS
> names, programme-related information or any other
> +text, then RadioText should be used.</entry>
This is slightly ambiguous. I would suggest changing the ending to:
"should be used in addition to <constant>V4L2_CID_RDS_PS_NAME</constant>."
> + </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.
> +The unit, step and range are driver-specific.</entry>
I thought the unit was useconds?
> + </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_PREEMPHASIS</constant> </entry>
> + <entry>integer</entry>
> + </row>
> + <row id="v4l2-fm-tx-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_fm_tx_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_FM_TX_PREEMPHASIS_DISABLED</constant> </entry>
> + <entry>No pre-emphasis is applied.</entry>
> + </row>
> + <row>
> +
> <entry><constant>V4L2_FM_TX_PREEMPHASIS_50_uS</constant> </entry>
> + <entry>A pre-emphasis of 50 uS is used.</entry>
> + </row>
> + <row>
> +
> <entry><constant>V4L2_FM_TX_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>
>
> <!--
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
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