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<refentry id="vidioc-enumoutput">
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<refentrytitle>ioctl VIDIOC_ENUMOUTPUT</refentrytitle>
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<refname>VIDIOC_ENUMOUTPUT</refname>
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<refpurpose>Enumerate video outputs</refpurpose>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>struct v4l2_output *<parameter>argp</parameter></paramdef>
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<title>Arguments</title>
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<term><parameter>fd</parameter></term>
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<term><parameter>request</parameter></term>
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<para>VIDIOC_ENUMOUTPUT</para>
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<term><parameter>argp</parameter></term>
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<title>Description</title>
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<para>To query the attributes of a video outputs applications
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initialize the <structfield>index</structfield> field of &v4l2-output;
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and call the <constant>VIDIOC_ENUMOUTPUT</constant> ioctl with a
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pointer to this structure. Drivers fill the rest of the structure or
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return an &EINVAL; when the index is out of bounds. To enumerate all
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outputs applications shall begin at index zero, incrementing by one
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until the driver returns <errorcode>EINVAL</errorcode>.</para>
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<table frame="none" pgwide="1" id="v4l2-output">
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<title>struct <structname>v4l2_output</structname></title>
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<entry><structfield>index</structfield></entry>
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<entry>Identifies the output, set by the
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<entry><structfield>name</structfield>[32]</entry>
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<entry>Name of the video output, a NUL-terminated ASCII
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string, for example: "Vout". This information is intended for the
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user, preferably the connector label on the device itself.</entry>
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<entry><structfield>type</structfield></entry>
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<entry>Type of the output, see <xref
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linkend="output-type" />.</entry>
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<entry><structfield>audioset</structfield></entry>
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<entry><para>Drivers can enumerate up to 32 video and
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audio outputs. This field shows which audio outputs were
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selectable as the current output if this was the currently selected
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video output. It is a bit mask. The LSB corresponds to audio output 0,
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the MSB to output 31. Any number of bits can be set, or
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none.</para><para>When the driver does not enumerate audio outputs no
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bits must be set. Applications shall not interpret this as lack of
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audio support. Drivers may automatically select audio outputs without
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enumerating them.</para><para>For details on audio outputs and how to
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select the current output see <xref linkend="audio" />.</para></entry>
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<entry><structfield>modulator</structfield></entry>
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<entry>Output devices can have zero or more RF modulators.
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When the <structfield>type</structfield> is
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<constant>V4L2_OUTPUT_TYPE_MODULATOR</constant> this is an RF
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connector and this field identifies the modulator. It corresponds to
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&v4l2-modulator; field <structfield>index</structfield>. For details
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on modulators see <xref linkend="tuner" />.</entry>
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<entry>&v4l2-std-id;</entry>
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<entry><structfield>std</structfield></entry>
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<entry>Every video output supports one or more different
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video standards. This field is a set of all supported standards. For
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details on video standards and how to switch see <xref
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linkend="standard" />.</entry>
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<entry><structfield>capabilities</structfield></entry>
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<entry>This field provides capabilities for the
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output. See <xref linkend="output-capabilities" /> for flags.</entry>
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<entry><structfield>reserved</structfield>[3]</entry>
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<entry>Reserved for future extensions. Drivers must set
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the array to zero.</entry>
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<table frame="none" pgwide="1" id="output-type">
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<title>Output Type</title>
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<entry><constant>V4L2_OUTPUT_TYPE_MODULATOR</constant></entry>
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<entry>This output is an analog TV modulator.</entry>
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<entry><constant>V4L2_OUTPUT_TYPE_ANALOG</constant></entry>
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<entry>Analog baseband output, for example Composite /
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CVBS, S-Video, RGB.</entry>
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<entry><constant>V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY</constant></entry>
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<!-- Capabilities flags based on video timings RFC by Muralidharan
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Karicheri, titled RFC (v1.2): V4L - Support for video timings at the
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input/output interface to linux-media@vger.kernel.org on 19 Oct 2009.
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<table frame="none" pgwide="1" id="output-capabilities">
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<title>Output capabilities</title>
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<entry><constant>V4L2_OUT_CAP_PRESETS</constant></entry>
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<entry>0x00000001</entry>
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<entry>This output supports setting DV presets by using VIDIOC_S_DV_PRESET.</entry>
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<entry><constant>V4L2_OUT_CAP_CUSTOM_TIMINGS</constant></entry>
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<entry>0x00000002</entry>
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<entry>This output supports setting custom video timings by using VIDIOC_S_DV_TIMINGS.</entry>
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<entry><constant>V4L2_OUT_CAP_STD</constant></entry>
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<entry>0x00000004</entry>
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<entry>This output supports setting the TV standard by using VIDIOC_S_STD.</entry>
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<term><errorcode>EINVAL</errorcode></term>
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<para>The &v4l2-output; <structfield>index</structfield>
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is out of bounds.</para>
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sgml-parent-document: "v4l2.sgml"
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