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Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-g-tuner.xml')
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diff --git a/Documentation/DocBook/v4l/vidioc-g-tuner.xml b/Documentation/DocBook/v4l/vidioc-g-tuner.xml new file mode 100644 index 0000000..bd98c73 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-tuner.xml @@ -0,0 +1,535 @@ +<refentry id="vidioc-g-tuner"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_TUNER</refname> + <refname>VIDIOC_S_TUNER</refname> + <refpurpose>Get or set tuner attributes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>const struct v4l2_tuner +*<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>VIDIOC_G_TUNER, VIDIOC_S_TUNER</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the attributes of a tuner applications initialize the +<structfield>index</structfield> field and zero out the +<structfield>reserved</structfield> array of a &v4l2-tuner; and call the +<constant>VIDIOC_G_TUNER</constant> ioctl with a pointer to this +structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all tuners +applications shall begin at index zero, incrementing by one until the +driver returns <errorcode>EINVAL</errorcode>.</para> + + <para>Tuners have two writable properties, the audio mode and +the radio frequency. To change the audio mode, applications initialize +the <structfield>index</structfield>, +<structfield>audmode</structfield> and +<structfield>reserved</structfield> fields and call the +<constant>VIDIOC_S_TUNER</constant> ioctl. This will +<emphasis>not</emphasis> change the current tuner, which is determined +by the current video input. Drivers may choose a different audio mode +if the requested mode is invalid or unsupported. Since this is a +<!-- FIXME -->write-only ioctl, it does not return the actually +selected audio mode.</para> + + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available.</para> + + <table pgwide="1" frame="none" id="v4l2-tuner"> + <title>struct <structname>v4l2_tuner</structname></title> + <tgroup cols="3"> + <colspec colname="c1" colwidth="1*" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colname="c3" colwidth="1*" /> + <colspec colname="c4" colwidth="1*" /> + <spanspec spanname="hspan" namest="c3" nameend="c4" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry spanname="hspan">Identifies the tuner, set by the +application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry spanname="hspan"><para>Name of the tuner, a +NUL-terminated ASCII string. This information is intended for the +user.<!-- FIXME Video inputs already have a name, the purpose of this +field is not quite clear.--></para></entry> + </row> + <row> + <entry>&v4l2-tuner-type;</entry> + <entry><structfield>type</structfield></entry> + <entry spanname="hspan">Type of the tuner, see <xref + linkend="v4l2-tuner-type" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry spanname="hspan"><para>Tuner capability flags, see +<xref linkend="tuner-capability" />. Audio flags indicate the ability +to decode audio subprograms. They will <emphasis>not</emphasis> +change, for example with the current video standard.</para><para>When +the structure refers to a radio tuner only the +<constant>V4L2_TUNER_CAP_LOW</constant>, +<constant>V4L2_TUNER_CAP_STEREO</constant> and +<constant>V4L2_TUNER_CAP_RDS</constant> flags can be set.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangelow</structfield></entry> + <entry spanname="hspan">The lowest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rangehigh</structfield></entry> + <entry spanname="hspan">The highest tunable frequency in +units of 62.5 kHz, or if the <structfield>capability</structfield> +flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 +Hz.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>rxsubchans</structfield></entry> + <entry spanname="hspan"><para>Some tuners or audio +decoders can determine the received audio subprograms by analyzing +audio carriers, pilot tones or other indicators. To pass this +information drivers set flags defined in <xref + linkend="tuner-rxsubchans" /> in this field. For +example:</para></entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>receiving mono audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>STEREO | SAP</constant></entry> + <entry>receiving stereo audio and a secondary audio +program</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO</constant></entry> + <entry>receiving mono or stereo audio, the hardware cannot +distinguish</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>receiving bilingual audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry><constant>MONO | STEREO | LANG1 | LANG2</constant></entry> + <entry>receiving mono, stereo or bilingual +audio</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry spanname="hspan"><para>When the +<constant>V4L2_TUNER_CAP_STEREO</constant>, +<constant>_LANG1</constant>, <constant>_LANG2</constant> or +<constant>_SAP</constant> flag is cleared in the +<structfield>capability</structfield> field, the corresponding +<constant>V4L2_TUNER_SUB_</constant> flag must not be set +here.</para><para>This field is valid only if this is the tuner of the +current video input, or when the structure refers to a radio +tuner.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>audmode</structfield></entry> + <entry spanname="hspan"><para>The selected audio mode, see +<xref linkend="tuner-audmode" /> for valid values. The audio mode does +not affect audio subprogram detection, and like a <link +linkend="control">control</link> it does not automatically change +unless the requested mode is invalid or unsupported. See <xref + linkend="tuner-matrix" /> for possible results when +the selected and received audio programs do not +match.</para><para>Currently this is the only field of struct +<structname>v4l2_tuner</structname> applications can +change.</para></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>signal</structfield></entry> + <entry spanname="hspan">The signal strength if known, ranging +from 0 to 65535. Higher values indicate a better signal.</entry> + </row> + <row> + <entry>__s32</entry> + <entry><structfield>afc</structfield></entry> + <entry spanname="hspan">Automatic frequency control: When the +<structfield>afc</structfield> value is negative, the frequency is too +low, when positive too high.<!-- FIXME need example what to do when it never +settles at zero, &ie; range is what? --></entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[4]</entry> + <entry spanname="hspan">Reserved for future extensions. Drivers and +applications must set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-tuner-type"> + <title>enum v4l2_tuner_type</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_RADIO</constant></entry> + <entry>1</entry> + <entry></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_ANALOG_TV</constant></entry> + <entry>2</entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-capability"> + <title>Tuner and Modulator Capability Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_CAP_LOW</constant></entry> + <entry>0x0001</entry> + <entry>When set, tuning frequencies are expressed in units of +62.5 Hz, otherwise in units of 62.5 kHz.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_NORM</constant></entry> + <entry>0x0002</entry> + <entry>This is a multi-standard tuner; the video standard +can or must be switched. (B/G PAL tuners for example are typically not + considered multi-standard because the video standard is automatically + determined from the frequency band.) The set of supported video + standards is available from the &v4l2-input; pointing to this tuner, + see the description of ioctl &VIDIOC-ENUMINPUT; for details. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_STEREO</constant></entry> + <entry>0x0010</entry> + <entry>Stereo audio reception is supported.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG1</constant></entry> + <entry>0x0040</entry> + <entry>Reception of the primary language of a bilingual +audio program is supported. Bilingual audio is a feature of +two-channel systems, transmitting the primary language monaural on the +main audio carrier and a secondary language monaural on a second +carrier. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_LANG2</constant></entry> + <entry>0x0020</entry> + <entry>Reception of the secondary language of a bilingual +audio program is supported. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_SAP</constant></entry> + <entry>0x0020</entry> + <entry><para>Reception of a secondary audio program is +supported. This is a feature of the BTSC system which accompanies the +NTSC video standard. Two audio carriers are available for mono or +stereo transmissions of a primary language, and an independent third +carrier for a monaural secondary language. Only + <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</para><para>Note the +<constant>V4L2_TUNER_CAP_LANG2</constant> and +<constant>V4L2_TUNER_CAP_SAP</constant> flags are synonyms. +<constant>V4L2_TUNER_CAP_SAP</constant> applies when the tuner +supports the <constant>V4L2_STD_NTSC_M</constant> video +standard.</para><!-- FIXME what if PAL+NTSC and Bi but not SAP? --></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_CAP_RDS</constant></entry> + <entry>0x0080</entry> + <entry>RDS capture is supported. This capability is only valid for +radio tuners.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-rxsubchans"> + <title>Tuner Audio Reception Flags</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> + <entry>0x0001</entry> + <entry>The tuner receives a mono audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> + <entry>0x0002</entry> + <entry>The tuner receives a stereo audio signal.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> + <entry>0x0008</entry> + <entry>The tuner receives the primary language of a +bilingual audio signal. Drivers must clear this flag when the current +video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives the secondary language of a +bilingual audio signal (or a second audio program).</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> + <entry>0x0004</entry> + <entry>The tuner receives a Second Audio Program. Note the +<constant>V4L2_TUNER_SUB_LANG2</constant> and +<constant>V4L2_TUNER_SUB_SAP</constant> flags are synonyms. The +<constant>V4L2_TUNER_SUB_SAP</constant> flag applies when the +current video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> + <entry>0x0010</entry> + <entry>The tuner receives an RDS channel.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="tuner-audmode"> + <title>Tuner Audio Modes</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_TUNER_MODE_MONO</constant></entry> + <entry>0</entry> + <entry>Play mono audio. When the tuner receives a stereo +signal this a down-mix of the left and right channel. When the tuner +receives a bilingual or SAP signal this mode selects the primary +language.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_STEREO</constant></entry> + <entry>1</entry> + <entry><para>Play stereo audio. When the tuner receives +bilingual audio it may play different languages on the left and right +channel or the primary language is played on both channels.</para><para>Playing +different languages in this mode is +deprecated. New drivers should do this only in +<constant>MODE_LANG1_LANG2</constant>.</para><para>When the tuner +receives no stereo signal or does not support stereo reception the +driver shall fall back to <constant>MODE_MONO</constant>.</para></entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1</constant></entry> + <entry>3</entry> + <entry>Play the primary language, mono or stereo. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG2</constant></entry> + <entry>2</entry> + <entry>Play the secondary language, mono. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_SAP</constant></entry> + <entry>2</entry> + <entry>Play the Second Audio Program. When the tuner +receives no bilingual audio or SAP, or their reception is not +supported the driver shall fall back to mono or stereo mode. Only +<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this mode. +Note the <constant>V4L2_TUNER_MODE_LANG2</constant> and +<constant>V4L2_TUNER_MODE_SAP</constant> are synonyms.</entry> + </row> + <row> + <entry><constant>V4L2_TUNER_MODE_LANG1_LANG2</constant></entry> + <entry>4</entry> + <entry>Play the primary language on the left channel, the +secondary language on the right channel. When the tuner receives no +bilingual audio or SAP, it shall fall back to +<constant>MODE_LANG1</constant> or <constant>MODE_MONO</constant>. +Only <constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this +mode.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="all" id="tuner-matrix"> + <title>Tuner Audio Matrix</title> + <tgroup cols="6" align="center"> + <colspec align="left" /> + <colspec colname="c2" colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colwidth="1*" /> + <colspec colnum="6" colname="c6" colwidth="1*" /> + <spanspec namest="c2" nameend="c6" spanname="hspan" align="center" /> + <thead> + <row> + <entry></entry> + <entry spanname="hspan">Selected +<constant>V4L2_TUNER_MODE_</constant></entry> + </row> + <row> + <entry>Received <constant>V4L2_TUNER_SUB_</constant></entry> + <entry><constant>MONO</constant></entry> + <entry><constant>STEREO</constant></entry> + <entry><constant>LANG1</constant></entry> + <entry><constant>LANG2 = SAP</constant></entry> + <entry><constant>LANG1_LANG2</constant><footnote><para>This +mode has been added in Linux 2.6.17 and may not be supported by older +drivers.</para></footnote></entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>MONO</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + </row> + <row> + <entry><constant>MONO | SAP</constant></entry> + <entry>Mono</entry> + <entry>Mono/Mono</entry> + <entry>Mono</entry> + <entry>SAP</entry> + <entry>Mono/SAP (preferred) or Mono/Mono</entry> + </row> + <row> + <entry><constant>STEREO</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>L/R (preferred) or L+R/L+R</entry> + </row> + <row> + <entry><constant>STEREO | SAP</constant></entry> + <entry>L+R</entry> + <entry>L/R</entry> + <entry>Stereo L/R (preferred) or Mono L+R</entry> + <entry>SAP</entry> + <entry>L+R/SAP (preferred) or L/R or L+R/L+R</entry> + </row> + <row> + <entry><constant>LANG1 | LANG2</constant></entry> + <entry>Language 1</entry> + <entry>Lang1/Lang2 (deprecated<footnote><para>Playback of +both languages in <constant>MODE_STEREO</constant> is deprecated. In +the future drivers should produce only the primary language in this +mode. Applications should request +<constant>MODE_LANG1_LANG2</constant> to record both languages or a +stereo signal.</para></footnote>) or +Lang1/Lang1</entry> + <entry>Language 1</entry> + <entry>Language 2</entry> + <entry>Lang1/Lang2 (preferred) or Lang1/Lang1</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-tuner; <structfield>index</structfield> is +out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> |
