mirror of https://gitee.com/openkylin/linux.git
332 lines
11 KiB
XML
332 lines
11 KiB
XML
<refentry id="vidioc-g-dv-timings">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_G_DV_TIMINGS</refname>
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<refname>VIDIOC_S_DV_TIMINGS</refname>
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<refpurpose>Get or set DV timings for input or output</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_dv_timings *<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_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</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 set DV timings for the input or output, applications use the
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<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current timings,
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applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing
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information is filled in using the structure &v4l2-dv-timings;. These ioctls take
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a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported
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or the timing values are not correct, the driver returns &EINVAL;.</para>
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<para>The <filename>linux/v4l2-dv-timings.h</filename> header can be used to get the
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timings of the formats in the <xref linkend="cea861" /> and <xref linkend="vesadmt" />
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standards. If the current input or output does not support DV timings (e.g. if
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&VIDIOC-ENUMINPUT; does not set the <constant>V4L2_IN_CAP_DV_TIMINGS</constant> flag), then
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&ENODATA; is returned.</para>
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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>This ioctl is not supported, or the
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<constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>ENODATA</errorcode></term>
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<listitem>
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<para>Digital video timings are not supported for this input or output.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>EBUSY</errorcode></term>
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<listitem>
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<para>The device is busy and therefore can not change the timings.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<table pgwide="1" frame="none" id="v4l2-bt-timings">
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<title>struct <structname>v4l2_bt_timings</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>width</structfield></entry>
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<entry>Width of the active video in pixels.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>height</structfield></entry>
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<entry>Height of the active video frame in lines. So for interlaced formats the
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height of the active video in each field is <structfield>height</structfield>/2.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>interlaced</structfield></entry>
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<entry>Progressive (0) or interlaced (1)</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>polarities</structfield></entry>
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<entry>This is a bit mask that defines polarities of sync signals.
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bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set
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(1) it is positive polarity and if is cleared (0), it is negative polarity.</entry>
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</row>
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<row>
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<entry>__u64</entry>
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<entry><structfield>pixelclock</structfield></entry>
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<entry>Pixel clock in Hz. Ex. 74.25MHz->74250000</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>hfrontporch</structfield></entry>
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<entry>Horizontal front porch in pixels</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>hsync</structfield></entry>
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<entry>Horizontal sync length in pixels</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>hbackporch</structfield></entry>
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<entry>Horizontal back porch in pixels</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>vfrontporch</structfield></entry>
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<entry>Vertical front porch in lines. For interlaced formats this refers to the
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odd field (aka field 1).</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>vsync</structfield></entry>
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<entry>Vertical sync length in lines. For interlaced formats this refers to the
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odd field (aka field 1).</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>vbackporch</structfield></entry>
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<entry>Vertical back porch in lines. For interlaced formats this refers to the
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odd field (aka field 1).</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>il_vfrontporch</structfield></entry>
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<entry>Vertical front porch in lines for the even field (aka field 2) of
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interlaced field formats.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>il_vsync</structfield></entry>
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<entry>Vertical sync length in lines for the even field (aka field 2) of
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interlaced field formats.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>il_vbackporch</structfield></entry>
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<entry>Vertical back porch in lines for the even field (aka field 2) of
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interlaced field formats.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>standards</structfield></entry>
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<entry>The video standard(s) this format belongs to. This will be filled in by
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the driver. Applications must set this to 0. See <xref linkend="dv-bt-standards"/>
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for a list of standards.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>flags</structfield></entry>
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<entry>Several flags giving more information about the format.
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See <xref linkend="dv-bt-flags"/> for a description of the flags.
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</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-dv-timings">
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<title>struct <structname>v4l2_dv_timings</structname></title>
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<tgroup cols="4">
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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>type</structfield></entry>
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<entry></entry>
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<entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry>
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</row>
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<row>
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<entry>union</entry>
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<entry><structfield></structfield></entry>
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<entry></entry>
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</row>
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<row>
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<entry></entry>
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<entry>&v4l2-bt-timings;</entry>
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<entry><structfield>bt</structfield></entry>
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<entry>Timings defined by BT.656/1120 specifications</entry>
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</row>
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<row>
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<entry></entry>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[32]</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="dv-timing-types">
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<title>DV Timing types</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>Timing type</entry>
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<entry>value</entry>
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<entry>Description</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry>
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<entry></entry>
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</row>
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<row>
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<entry>V4L2_DV_BT_656_1120</entry>
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<entry>0</entry>
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<entry>BT.656/1120 timings</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="dv-bt-standards">
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<title>DV BT Timing standards</title>
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<tgroup cols="2">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>Timing standard</entry>
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<entry>Description</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry>
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</row>
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<row>
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<entry>V4L2_DV_BT_STD_CEA861</entry>
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<entry>The timings follow the CEA-861 Digital TV Profile standard</entry>
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</row>
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<row>
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<entry>V4L2_DV_BT_STD_DMT</entry>
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<entry>The timings follow the VESA Discrete Monitor Timings standard</entry>
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</row>
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<row>
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<entry>V4L2_DV_BT_STD_CVT</entry>
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<entry>The timings follow the VESA Coordinated Video Timings standard</entry>
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</row>
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<row>
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<entry>V4L2_DV_BT_STD_GTF</entry>
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<entry>The timings follow the VESA Generalized Timings Formula standard</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="dv-bt-flags">
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<title>DV BT Timing flags</title>
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<tgroup cols="2">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>Flag</entry>
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<entry>Description</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry>
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</row>
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<row>
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<entry>V4L2_DV_FL_REDUCED_BLANKING</entry>
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<entry>CVT/GTF specific: the timings use reduced blanking (CVT) or the 'Secondary
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GTF' curve (GTF). In both cases the horizontal and/or vertical blanking
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intervals are reduced, allowing a higher resolution over the same
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bandwidth. This is a read-only flag, applications must not set this.
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</entry>
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</row>
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<row>
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<entry>V4L2_DV_FL_CAN_REDUCE_FPS</entry>
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<entry>CEA-861 specific: set for CEA-861 formats with a framerate that is a multiple
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of six. These formats can be optionally played at 1 / 1.001 speed to
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be compatible with 60 Hz based standards such as NTSC and PAL-M that use a framerate of
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29.97 frames per second. If the transmitter can't generate such frequencies, then the
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flag will also be cleared. This is a read-only flag, applications must not set this.
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</entry>
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</row>
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<row>
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<entry>V4L2_DV_FL_REDUCED_FPS</entry>
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<entry>CEA-861 specific: only valid for video transmitters, the flag is cleared
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by receivers. It is also only valid for formats with the V4L2_DV_FL_CAN_REDUCE_FPS flag
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set, for other formats the flag will be cleared by the driver.
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If the application sets this flag, then the pixelclock used to set up the transmitter is
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divided by 1.001 to make it compatible with NTSC framerates. If the transmitter
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can't generate such frequencies, then the flag will also be cleared.
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</entry>
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</row>
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<row>
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<entry>V4L2_DV_FL_HALF_LINE</entry>
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<entry>Specific to interlaced formats: if set, then field 1 (aka the odd field)
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is really one half-line longer and field 2 (aka the even field) is really one half-line
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shorter, so each field has exactly the same number of half-lines. Whether half-lines can be
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detected or used depends on the hardware.
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</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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</refentry>
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