mirror of https://gitee.com/openkylin/linux.git
392 lines
14 KiB
XML
392 lines
14 KiB
XML
<refentry id="vidioc-enumstd">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_ENUMSTD</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_ENUMSTD</refname>
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<refpurpose>Enumerate supported video standards</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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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_standard *<parameter>argp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>&fd;</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>VIDIOC_ENUMSTD</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<para>To query the attributes of a video standard,
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especially a custom (driver defined) one, applications initialize the
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<structfield>index</structfield> field of &v4l2-standard; and call the
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<constant>VIDIOC_ENUMSTD</constant> ioctl with a pointer to this
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structure. Drivers fill the rest of the structure or return an
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&EINVAL; when the index is out of bounds. To enumerate all standards
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applications shall begin at index zero, incrementing by one until the
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driver returns <errorcode>EINVAL</errorcode>. Drivers may enumerate a
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different set of standards after switching the video input or
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output.<footnote>
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<para>The supported standards may overlap and we need an
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unambiguous set to find the current standard returned by
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<constant>VIDIOC_G_STD</constant>.</para>
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</footnote></para>
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<table pgwide="1" frame="none" id="v4l2-standard">
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<title>struct <structname>v4l2_standard</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u32</entry>
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<entry><structfield>index</structfield></entry>
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<entry>Number of the video standard, set by the
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application.</entry>
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</row>
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<row>
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<entry>&v4l2-std-id;</entry>
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<entry><structfield>id</structfield></entry>
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<entry>The bits in this field identify the standard as
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one of the common standards listed in <xref linkend="v4l2-std-id" />,
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or if bits 32 to 63 are set as custom standards. Multiple bits can be
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set if the hardware does not distinguish between these standards,
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however separate indices do not indicate the opposite. The
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<structfield>id</structfield> must be unique. No other enumerated
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<structname>v4l2_standard</structname> structure, for this input or
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output anyway, can contain the same set of bits.</entry>
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</row>
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<row>
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<entry>__u8</entry>
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<entry><structfield>name</structfield>[24]</entry>
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<entry>Name of the standard, a NUL-terminated ASCII
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string, for example: "PAL-B/G", "NTSC Japan". This information is
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intended for the user.</entry>
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</row>
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<row>
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<entry>&v4l2-fract;</entry>
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<entry><structfield>frameperiod</structfield></entry>
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<entry>The frame period (not field period) is numerator
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/ denominator. For example M/NTSC has a frame period of 1001 /
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30000 seconds.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>framelines</structfield></entry>
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<entry>Total lines per frame including blanking,
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e. g. 625 for B/PAL.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[4]</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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</row>
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</tbody>
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</tgroup>
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</table>
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<table pgwide="1" frame="none" id="v4l2-fract">
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<title>struct <structname>v4l2_fract</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u32</entry>
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<entry><structfield>numerator</structfield></entry>
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<entry></entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>denominator</structfield></entry>
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<entry></entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<table pgwide="1" frame="none" id="v4l2-std-id">
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<title>typedef <structname>v4l2_std_id</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u64</entry>
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<entry><structfield>v4l2_std_id</structfield></entry>
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<entry>This type is a set, each bit representing another
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video standard as listed below and in <xref
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linkend="video-standards" />. The 32 most significant bits are reserved
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for custom (driver defined) video standards.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para><programlisting>
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#define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001)
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#define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002)
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#define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004)
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#define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008)
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#define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010)
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#define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020)
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#define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040)
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#define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080)
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#define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100)
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#define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200)
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#define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400)
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#define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800)
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</programlisting></para><para><constant>V4L2_STD_PAL_60</constant> is
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a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color
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modulation with a 4.43 MHz color subcarrier. Some PAL video recorders
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can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic
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PAL TV.</para><para><programlisting>
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#define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000)
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#define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000)
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#define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000)
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</programlisting></para><para><constant>V4L2_STD_NTSC_443</constant>
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is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC
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color modulation with a 4.43 MHz color
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subcarrier.</para><para><programlisting>
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#define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000)
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#define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000)
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#define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000)
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#define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000)
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#define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000)
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#define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000)
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#define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000)
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#define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000)
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#define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000)
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/* ATSC/HDTV */
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#define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000)
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#define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000)
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</programlisting></para><para><!-- ATSC proposal by Mark McClelland,
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video4linux-list@redhat.com on 17 Oct 2002
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--><constant>V4L2_STD_ATSC_8_VSB</constant> and
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<constant>V4L2_STD_ATSC_16_VSB</constant> are U.S. terrestrial digital
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TV standards. Presently the V4L2 API does not support digital TV. See
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also the Linux DVB API at <ulink
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url="http://linuxtv.org">http://linuxtv.org</ulink>.</para>
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<para><programlisting>
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#define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\
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V4L2_STD_PAL_B1 |\
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V4L2_STD_PAL_G)
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#define V4L2_STD_B (V4L2_STD_PAL_B |\
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V4L2_STD_PAL_B1 |\
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V4L2_STD_SECAM_B)
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#define V4L2_STD_GH (V4L2_STD_PAL_G |\
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V4L2_STD_PAL_H |\
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V4L2_STD_SECAM_G |\
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V4L2_STD_SECAM_H)
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#define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\
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V4L2_STD_PAL_D1 |\
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V4L2_STD_PAL_K)
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#define V4L2_STD_PAL (V4L2_STD_PAL_BG |\
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V4L2_STD_PAL_DK |\
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V4L2_STD_PAL_H |\
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V4L2_STD_PAL_I)
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#define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\
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V4L2_STD_NTSC_M_JP |\
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V4L2_STD_NTSC_M_KR)
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#define V4L2_STD_MN (V4L2_STD_PAL_M |\
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V4L2_STD_PAL_N |\
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V4L2_STD_PAL_Nc |\
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V4L2_STD_NTSC)
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#define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\
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V4L2_STD_SECAM_K |\
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V4L2_STD_SECAM_K1)
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#define V4L2_STD_DK (V4L2_STD_PAL_DK |\
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V4L2_STD_SECAM_DK)
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#define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\
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V4L2_STD_SECAM_G |\
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V4L2_STD_SECAM_H |\
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V4L2_STD_SECAM_DK |\
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V4L2_STD_SECAM_L |\
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V4L2_STD_SECAM_LC)
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#define V4L2_STD_525_60 (V4L2_STD_PAL_M |\
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V4L2_STD_PAL_60 |\
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V4L2_STD_NTSC |\
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V4L2_STD_NTSC_443)
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#define V4L2_STD_625_50 (V4L2_STD_PAL |\
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V4L2_STD_PAL_N |\
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V4L2_STD_PAL_Nc |\
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V4L2_STD_SECAM)
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#define V4L2_STD_UNKNOWN 0
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#define V4L2_STD_ALL (V4L2_STD_525_60 |\
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V4L2_STD_625_50)
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</programlisting></para>
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<table pgwide="1" id="video-standards" orient="land">
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<title>Video Standards (based on [<xref linkend="itu470" />])</title>
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<tgroup cols="12" colsep="1" rowsep="1" align="center">
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<colspec colname="c1" align="left" />
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<colspec colname="c2" />
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<colspec colname="c3" />
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<colspec colname="c4" />
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<colspec colname="c5" />
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<colspec colnum="7" colname="c7" />
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<colspec colnum="9" colname="c9" />
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<colspec colnum="12" colname="c12" />
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<spanspec namest="c2" nameend="c3" spanname="m" align="center" />
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<spanspec namest="c4" nameend="c12" spanname="x" align="center" />
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<spanspec namest="c5" nameend="c7" spanname="b" align="center" />
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<spanspec namest="c9" nameend="c12" spanname="s" align="center" />
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<thead>
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<row>
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<entry>Characteristics</entry>
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<entry><para>M/NTSC<footnote><para>Japan uses a standard
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similar to M/NTSC
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(V4L2_STD_NTSC_M_JP).</para></footnote></para></entry>
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<entry>M/PAL</entry>
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<entry><para>N/PAL<footnote><para> The values in
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brackets apply to the combination N/PAL a.k.a.
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N<subscript>C</subscript> used in Argentina
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(V4L2_STD_PAL_Nc).</para></footnote></para></entry>
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<entry align="center">B, B1, G/PAL</entry>
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<entry align="center">D, D1, K/PAL</entry>
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<entry align="center">H/PAL</entry>
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<entry align="center">I/PAL</entry>
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<entry align="center">B, G/SECAM</entry>
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<entry align="center">D, K/SECAM</entry>
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<entry align="center">K1/SECAM</entry>
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<entry align="center">L/SECAM</entry>
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</row>
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</thead>
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<tbody valign="top">
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<row>
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<entry>Frame lines</entry>
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<entry spanname="m">525</entry>
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<entry spanname="x">625</entry>
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</row>
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<row>
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<entry>Frame period (s)</entry>
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<entry spanname="m">1001/30000</entry>
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<entry spanname="x">1/25</entry>
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</row>
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<row>
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<entry>Chrominance sub-carrier frequency (Hz)</entry>
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<entry>3579545 ± 10</entry>
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<entry>3579611.49 ± 10</entry>
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<entry>4433618.75 ± 5 (3582056.25
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± 5)</entry>
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<entry spanname="b">4433618.75 ± 5</entry>
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<entry>4433618.75 ± 1</entry>
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<entry spanname="s">f<subscript>OR</subscript> =
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4406250 ± 2000, f<subscript>OB</subscript> = 4250000
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± 2000</entry>
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</row>
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<row>
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<entry>Nominal radio-frequency channel bandwidth
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(MHz)</entry>
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<entry>6</entry>
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<entry>6</entry>
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<entry>6</entry>
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<entry>B: 7; B1, G: 8</entry>
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<entry>8</entry>
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<entry>8</entry>
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<entry>8</entry>
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<entry>8</entry>
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<entry>8</entry>
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<entry>8</entry>
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<entry>8</entry>
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</row>
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<row>
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<entry>Sound carrier relative to vision carrier
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(MHz)</entry>
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<entry>+ 4.5</entry>
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<entry>+ 4.5</entry>
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<entry>+ 4.5</entry>
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<entry><para>+ 5.5 ± 0.001
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<footnote><para>In the Federal Republic of Germany, Austria, Italy,
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the Netherlands, Slovakia and Switzerland a system of two sound
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carriers is used, the frequency of the second carrier being
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242.1875 kHz above the frequency of the first sound carrier. For
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stereophonic sound transmissions a similar system is used in
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Australia.</para></footnote> <footnote><para>New Zealand uses a sound
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carrier displaced 5.4996 ± 0.0005 MHz from the vision
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carrier.</para></footnote> <footnote><para>In Denmark, Finland, New
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Zealand, Sweden and Spain a system of two sound carriers is used. In
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Iceland, Norway and Poland the same system is being introduced. The
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second carrier is 5.85 MHz above the vision carrier and is DQPSK
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modulated with 728 kbit/s sound and data multiplex. (NICAM
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system)</para></footnote> <footnote><para>In the United Kingdom, a
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system of two sound carriers is used. The second sound carrier is
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6.552 MHz above the vision carrier and is DQPSK modulated with a
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728 kbit/s sound and data multiplex able to carry two sound
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channels. (NICAM system)</para></footnote></para></entry>
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<entry>+ 6.5 ± 0.001</entry>
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<entry>+ 5.5</entry>
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<entry>+ 5.9996 ± 0.0005</entry>
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<entry>+ 5.5 ± 0.001</entry>
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<entry>+ 6.5 ± 0.001</entry>
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<entry>+ 6.5</entry>
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<entry><para>+ 6.5 <footnote><para>In France, a
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digital carrier 5.85 MHz away from the vision carrier may be used in
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addition to the main sound carrier. It is modulated in differentially
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encoded QPSK with a 728 kbit/s sound and data multiplexer capable of
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carrying two sound channels. (NICAM
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system)</para></footnote></para></entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</refsect1>
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<refsect1>
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&return-value;
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<variablelist>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The &v4l2-standard; <structfield>index</structfield>
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is out of bounds.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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</refentry>
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<!--
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Local Variables:
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mode: sgml
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sgml-parent-document: "v4l2.sgml"
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indent-tabs-mode: nil
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End:
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-->
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