Re: [PATCHv7 5/9] v4l2-spec: Add documentation description for FM TX extended control class

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Hi Hans,

On Sun, Jun 14, 2009 at 1:41 PM, Hans Verkuil<hverkuil@xxxxxxxxx> wrote:
> 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 <eduardo.valentin@xxxxxxxxx>
>> ---
>>  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&nbsp;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&nbsp;300&nbsp;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>&nbsp;</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>&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>
>
> coding -> encodes

Right.

>
>> +       </row>
>> +       <row>
>> +         <entry spanname="id"><constant>V4L2_CID_RDS_PS_NAME</constant>&nbsp;</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>&nbsp;</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>."

I see. I'll change this.

>
>> +       </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>
>
> I thought the unit was useconds?

Yeah. Changing.

>
>> +       </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 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&nbsp;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>&nbsp;</entry>
>> +                   <entry>No pre-emphasis is applied.</entry>
>> +                 </row>
>> +                 <row>
>> +                   <entry><constant>V4L2_FM_TX_PREEMPHASIS_50_uS</constant>&nbsp;</entry>
>> +                   <entry>A pre-emphasis of 50 uS is used.</entry>
>> +                 </row>
>> +                 <row>
>> +                   <entry><constant>V4L2_FM_TX_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>
>> +
>> +<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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-- 
Eduardo Bezerra Valentin
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