Skip to content

L
linux
Commit 7dcc606b authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files
Options

[media] V4L2 spec: document the new V4L2 DV timings ioctls 

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 06bba75d
Hide whitespace changes
Inline Side-by-side
Showing with 633 additions and 29 deletions
Documentation/DocBook/media/v4l/biblio.xml
View file @ 7dcc606b
......@@ -208,4 +208,22 @@ in the frequency range from 87,5 to 108,0 MHz</title>
recommended exposure index</title>
</biblioentry>
<biblioentry id="cea861">
<abbrev>CEA-861-E</abbrev>
<authorgroup>
<corpauthor>Consumer Electronics Association
(<ulink url="http://www.ce.org">http://www.ce.org</ulink>)</corpauthor>
</authorgroup>
<title>A DTV Profile for Uncompressed High Speed Digital Interfaces</title>
</biblioentry>
<biblioentry id="vesadmt">
<abbrev>VESA&nbsp;DMT</abbrev>
<authorgroup>
<corpauthor>Video Electronics Standards Association
(<ulink url="http://www.vesa.org">http://www.vesa.org</ulink>)</corpauthor>
</authorgroup>
<title>VESA and Industry Standards and Guidelines for Computer Display Monitor Timing (DMT)</title>
</biblioentry>
</bibliography>
Documentation/DocBook/media/v4l/common.xml
View file @ 7dcc606b
......@@ -724,41 +724,47 @@ if (-1 == ioctl (fd, &VIDIOC-S-STD;, &amp;std_id)) {
}
</programlisting>
</example>
</section>
<section id="dv-timings">
<title>Digital Video (DV) Timings</title>
<para>
The video standards discussed so far has been dealing with Analog TV and the
The video standards discussed so far have been dealing with Analog TV and the
corresponding video timings. Today there are many more different hardware interfaces
such as High Definition TV interfaces (HDMI), VGA, DVI connectors etc., that carry
video signals and there is a need to extend the API to select the video timings
for these interfaces. Since it is not possible to extend the &v4l2-std-id; due to
the limited bits available, a new set of IOCTLs is added to set/get video timings at
the limited bits available, a new set of IOCTLs was added to set/get video timings at
the input and output: </para><itemizedlist>
<listitem>
<para>DV Timings: This will allow applications to define detailed
video timings for the interface. This includes parameters such as width, height,
polarities, frontporch, backporch etc. The <filename>linux/v4l2-dv-timings.h</filename>
header can be used to get the timings of the formats in the <xref linkend="cea861" /> and
<xref linkend="vesadmt" /> standards.
</para>
</listitem>
<listitem>
<para>DV Presets: Digital Video (DV) presets. These are IDs representing a
video timing at the input/output. Presets are pre-defined timings implemented
by the hardware according to video standards. A __u32 data type is used to represent
a preset unlike the bit mask that is used in &v4l2-std-id; allowing future extensions
to support as many different presets as needed.</para>
</listitem>
<listitem>
<para>Custom DV Timings: This will allow applications to define more detailed
custom video timings for the interface. This includes parameters such as width, height,
polarities, frontporch, backporch etc.
</para>
</listitem>
</itemizedlist>
<para>To enumerate and query the attributes of the DV timings supported by a device,
applications use the &VIDIOC-ENUM-DV-TIMINGS; and &VIDIOC-DV-TIMINGS-CAP; ioctls.
To set DV timings for the device, applications use the
&VIDIOC-S-DV-TIMINGS; ioctl and to get current DV timings they use the
&VIDIOC-G-DV-TIMINGS; ioctl. To detect the DV timings as seen by the video receiver applications
use the &VIDIOC-QUERY-DV-TIMINGS; ioctl.</para>
<para>To enumerate and query the attributes of DV presets supported by a device,
applications use the &VIDIOC-ENUM-DV-PRESETS; ioctl. To get the current DV preset,
applications use the &VIDIOC-G-DV-PRESET; ioctl and to set a preset they use the
&VIDIOC-S-DV-PRESET; ioctl.</para>
<para>To set custom DV timings for the device, applications use the
&VIDIOC-S-DV-TIMINGS; ioctl and to get current custom DV timings they use the
&VIDIOC-G-DV-TIMINGS; ioctl.</para>
&VIDIOC-S-DV-PRESET; ioctl. To detect the preset as seen by the video receiver applications
use the &VIDIOC-QUERY-DV-PRESET; ioctl.</para>
<para>Applications can make use of the <xref linkend="input-capabilities" /> and
<xref linkend="output-capabilities"/> flags to decide what ioctls are available to set the
video timings for the device.</para>
</section>
</section>
&sub-controls;
......
Documentation/DocBook/media/v4l/compat.xml
View file @ 7dcc606b
......@@ -2407,6 +2407,11 @@ details.</para>
<para>Added <link linkend="jpeg-controls">JPEG compression control
class</link>.</para>
</listitem>
<listitem>
<para>Extended the DV Timings API:
&VIDIOC-ENUM-DV-TIMINGS;, &VIDIOC-QUERY-DV-TIMINGS; and
&VIDIOC-DV-TIMINGS-CAP;.</para>
</listitem>
</orderedlist>
</section>
......@@ -2548,6 +2553,10 @@ and may change in the future.</para>
</listitem>
<listitem>
<para>&VIDIOC-ENCODER-CMD; and &VIDIOC-TRY-ENCODER-CMD;
ioctls.</para>
</listitem>
<listitem>
<para>&VIDIOC-DECODER-CMD; and &VIDIOC-TRY-DECODER-CMD;
ioctls.</para>
</listitem>
<listitem>
......@@ -2557,6 +2566,10 @@ ioctls.</para>
<listitem>
<para>&VIDIOC-DBG-G-CHIP-IDENT; ioctl.</para>
</listitem>
<listitem>
<para>&VIDIOC-ENUM-DV-TIMINGS;, &VIDIOC-QUERY-DV-TIMINGS; and
&VIDIOC-DV-TIMINGS-CAP; ioctls.</para>
</listitem>
<listitem>
<para>Flash API. <xref linkend="flash-controls" /></para>
</listitem>
......
Documentation/DocBook/media/v4l/v4l2.xml
View file @ 7dcc606b
......@@ -28,8 +28,8 @@ documentation.</contrib>
<firstname>Hans</firstname>
<surname>Verkuil</surname>
<contrib>Designed and documented the VIDIOC_LOG_STATUS ioctl,
the extended control ioctls and major parts of the sliced VBI
API.</contrib>
the extended control ioctls, major parts of the sliced VBI API, the
MPEG encoder and decoder APIs and the DV Timings API.</contrib>
<affiliation>
<address>
<email>hverkuil@xs4all.nl</email>
......@@ -123,6 +123,7 @@ Remote Controller chapter.</contrib>
<year>2009</year>
<year>2010</year>
<year>2011</year>
<year>2012</year>
<holder>Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin
Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab,
Pawel Osciak</holder>
......@@ -153,6 +154,11 @@ applications. -->
V4L2_CID_AUTO_FOCUS_STOP, V4L2_CID_AUTO_FOCUS_STATUS
and V4L2_CID_AUTO_FOCUS_RANGE.
</revremark>
<date>2012-05-01</date>
<authorinitials>hv</authorinitials>
<revremark>Added VIDIOC_ENUM_DV_TIMINGS, VIDIOC_QUERY_DV_TIMINGS and
VIDIOC_DV_TIMINGS_CAP.
</revremark>
</revision>
<revision>
......@@ -461,7 +467,7 @@ and discussions on the V4L mailing list.</revremark>
</partinfo>
<title>Video for Linux Two API Specification</title>
<subtitle>Revision 3.3</subtitle>
<subtitle>Revision 3.5</subtitle>
<chapter id="common">
&sub-common;
......@@ -519,10 +525,12 @@ and discussions on the V4L mailing list.</revremark>
&sub-dbg-g-register;
&sub-decoder-cmd;
&sub-dqevent;
&sub-dv-timings-cap;
&sub-encoder-cmd;
&sub-enumaudio;
&sub-enumaudioout;
&sub-enum-dv-presets;
&sub-enum-dv-timings;
&sub-enum-fmt;
&sub-enum-framesizes;
&sub-enum-frameintervals;
......@@ -557,6 +565,7 @@ and discussions on the V4L mailing list.</revremark>
&sub-querycap;
&sub-queryctrl;
&sub-query-dv-preset;
&sub-query-dv-timings;
&sub-querystd;
&sub-prepare-buf;
&sub-reqbufs;
......
Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
View file @ 7dcc606b
......@@ -48,6 +48,12 @@
<refsect1>
<title>Description</title>
<note>
<title>Experimental</title>
<para>This is an <link linkend="experimental"> experimental </link>
interface and may change in the future.</para>
</note>
<para>This ioctl is used to create buffers for <link linkend="mmap">memory
mapped</link> or <link linkend="userp">user pointer</link>
I/O. It can be used as an alternative or in addition to the
......
Documentation/DocBook/media/v4l/vidioc-dv-timings-cap.xml 0 → 100644
View file @ 7dcc606b
<refentry id="vidioc-dv-timings-cap">
<refmeta>
<refentrytitle>ioctl VIDIOC_DV_TIMINGS_CAP</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_DV_TIMINGS_CAP</refname>
<refpurpose>The capabilities of the Digital Video receiver/transmitter</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_dv_timings_cap *<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_DV_TIMINGS_CAP</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<note>
<title>Experimental</title>
<para>This is an <link linkend="experimental"> experimental </link>
interface and may change in the future.</para>
</note>
<para>To query the available timings, applications initialize the
<structfield>index</structfield> field and zero the reserved array of &v4l2-dv-timings-cap;
and call the <constant>VIDIOC_DV_TIMINGS_CAP</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 supported DV timings,
applications shall begin at index zero, incrementing by one until the
driver returns <errorcode>EINVAL</errorcode>. Note that drivers may enumerate a
different set of DV timings after switching the video input or
output.</para>
<table pgwide="1" frame="none" id="v4l2-bt-timings-cap">
<title>struct <structname>v4l2_bt_timings_cap</structname></title>
<tgroup cols="3">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>min_width</structfield></entry>
<entry>Minimum width of the active video in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>max_width</structfield></entry>
<entry>Maximum width of the active video in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>min_height</structfield></entry>
<entry>Minimum height of the active video in lines.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>max_height</structfield></entry>
<entry>Maximum height of the active video in lines.</entry>
</row>
<row>
<entry>__u64</entry>
<entry><structfield>min_pixelclock</structfield></entry>
<entry>Minimum pixelclock frequency in Hz.</entry>
</row>
<row>
<entry>__u64</entry>
<entry><structfield>max_pixelclock</structfield></entry>
<entry>Maximum pixelclock frequency in Hz.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>standards</structfield></entry>
<entry>The video standard(s) supported by the hardware.
See <xref linkend="dv-bt-standards"/> for a list of standards.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>capabilities</structfield></entry>
<entry>Several flags giving more information about the capabilities.
See <xref linkend="dv-bt-cap-capabilities"/> for a description of the flags.
</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[16]</entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="v4l2-dv-timings-cap">
<title>struct <structname>v4l2_dv_timings_cap</structname></title>
<tgroup cols="4">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[3]</entry>
<entry>Reserved for future extensions. Drivers must set the array to zero.</entry>
</row>
<row>
<entry>union</entry>
<entry><structfield></structfield></entry>
<entry></entry>
</row>
<row>
<entry></entry>
<entry>&v4l2-bt-timings-cap;</entry>
<entry><structfield>bt</structfield></entry>
<entry>BT.656/1120 timings capabilities of the hardware.</entry>
</row>
<row>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>raw_data</structfield>[32]</entry>
<entry></entry>
</row>
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="dv-bt-cap-capabilities">
<title>DV BT Timing capabilities</title>
<tgroup cols="2">
&cs-str;
<tbody valign="top">
<row>
<entry>Flag</entry>
<entry>Description</entry>
</row>
<row>
<entry></entry>
<entry></entry>
</row>
<row>
<entry>V4L2_DV_BT_CAP_INTERLACED</entry>
<entry>Interlaced formats are supported.
</entry>
</row>
<row>
<entry>V4L2_DV_BT_CAP_PROGRESSIVE</entry>
<entry>Progressive formats are supported.
</entry>
</row>
<row>
<entry>V4L2_DV_BT_CAP_REDUCED_BLANKING</entry>
<entry>CVT/GTF specific: the timings can make use of reduced blanking (CVT)
or the 'Secondary GTF' curve (GTF).
</entry>
</row>
<row>
<entry>V4L2_DV_BT_CAP_CUSTOM</entry>
<entry>Can support non-standard timings, i.e. timings not belonging to the
standards set in the <structfield>standards</structfield> field.
</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
&return-value;
</refsect1>
</refentry>
<!--
Local Variables:
mode: sgml
sgml-parent-document: "v4l2.sgml"
indent-tabs-mode: nil
End:
-->
Documentation/DocBook/media/v4l/vidioc-enum-dv-presets.xml
View file @ 7dcc606b
......@@ -48,6 +48,10 @@
<refsect1>
<title>Description</title>
<para>This ioctl is <emphasis role="bold">deprecated</emphasis>.
New drivers and applications should use &VIDIOC-ENUM-DV-TIMINGS; instead.
</para>
<para>To query the attributes of a DV preset, applications initialize the
<structfield>index</structfield> field and zero the reserved array of &v4l2-dv-enum-preset;
and call the <constant>VIDIOC_ENUM_DV_PRESETS</constant> ioctl with a pointer to this
......
Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml 0 → 100644
View file @ 7dcc606b
<refentry id="vidioc-enum-dv-timings">
<refmeta>
<refentrytitle>ioctl VIDIOC_ENUM_DV_TIMINGS</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_ENUM_DV_TIMINGS</refname>
<refpurpose>Enumerate supported Digital Video timings</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_enum_dv_timings *<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_ENUM_DV_TIMINGS</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<note>
<title>Experimental</title>
<para>This is an <link linkend="experimental"> experimental </link>
interface and may change in the future.</para>
</note>
<para>While some DV receivers or transmitters support a wide range of timings, others
support only a limited number of timings. With this ioctl applications can enumerate a list
of known supported timings. Call &VIDIOC-DV-TIMINGS-CAP; to check if it also supports other
standards or even custom timings that are not in this list.</para>
<para>To query the available timings, applications initialize the
<structfield>index</structfield> field and zero the reserved array of &v4l2-enum-dv-timings;
and call the <constant>VIDIOC_ENUM_DV_TIMINGS</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 supported DV timings,
applications shall begin at index zero, incrementing by one until the
driver returns <errorcode>EINVAL</errorcode>. Note that drivers may enumerate a
different set of DV timings after switching the video input or
output.</para>
<table pgwide="1" frame="none" id="v4l2-enum-dv-timings">
<title>struct <structname>v4l2_enum_dv_timings</structname></title>
<tgroup cols="3">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>index</structfield></entry>
<entry>Number of the DV timings, set by the
application.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[3]</entry>
<entry>Reserved for future extensions. Drivers must set the array to zero.</entry>
</row>
<row>
<entry>&v4l2-dv-timings;</entry>
<entry><structfield>timings</structfield></entry>
<entry>The timings.</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The &v4l2-enum-dv-timings; <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:
-->
Documentation/DocBook/media/v4l/vidioc-enuminput.xml
View file @ 7dcc606b
......@@ -285,7 +285,7 @@ input/output interface to linux-media@vger.kernel.org on 19 Oct 2009.
<row>
<entry><constant>V4L2_IN_CAP_CUSTOM_TIMINGS</constant></entry>
<entry>0x00000002</entry>
<entry>This input supports setting custom video timings by using VIDIOC_S_DV_TIMINGS.</entry>
<entry>This input supports setting video timings by using VIDIOC_S_DV_TIMINGS.</entry>
</row>
<row>
<entry><constant>V4L2_IN_CAP_STD</constant></entry>
......
Documentation/DocBook/media/v4l/vidioc-enumoutput.xml
View file @ 7dcc606b
......@@ -170,7 +170,7 @@ input/output interface to linux-media@vger.kernel.org on 19 Oct 2009.
<row>
<entry><constant>V4L2_OUT_CAP_CUSTOM_TIMINGS</constant></entry>
<entry>0x00000002</entry>
<entry>This output supports setting custom video timings by using VIDIOC_S_DV_TIMINGS.</entry>
<entry>This output supports setting video timings by using VIDIOC_S_DV_TIMINGS.</entry>
</row>
<row>
<entry><constant>V4L2_OUT_CAP_STD</constant></entry>
......
Documentation/DocBook/media/v4l/vidioc-g-dv-timings.xml
View file @ 7dcc606b
......@@ -7,7 +7,7 @@
<refnamediv>
<refname>VIDIOC_G_DV_TIMINGS</refname>
<refname>VIDIOC_S_DV_TIMINGS</refname>
<refpurpose>Get or set custom DV timings for input or output</refpurpose>
<refpurpose>Get or set DV timings for input or output</refpurpose>
</refnamediv>
<refsynopsisdiv>
......@@ -48,12 +48,15 @@
<refsect1>
<title>Description</title>
<para>To set custom DV timings for the input or output, applications use the
<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current custom timings,
<para>To set DV timings for the input or output, applications use the
<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current timings,
applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing
information is filled in using the structure &v4l2-dv-timings;. These ioctls take
a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported
or the timing values are not correct, the driver returns &EINVAL;.</para>
<para>The <filename>linux/v4l2-dv-timings.h</filename> header can be used to get the
timings of the formats in the <xref linkend="cea861" /> and <xref linkend="vesadmt" />
standards.</para>
</refsect1>
<refsect1>
......@@ -83,12 +86,13 @@ or the timing values are not correct, the driver returns &EINVAL;.</para>
<row>
<entry>__u32</entry>
<entry><structfield>width</structfield></entry>
<entry>Width of the active video in pixels</entry>
<entry>Width of the active video in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>height</structfield></entry>
<entry>Height of the active video in lines</entry>
<entry>Height of the active video frame in lines. So for interlaced formats the
height of the active video in each field is <structfield>height</structfield>/2.</entry>
</row>
<row>
<entry>__u32</entry>
......@@ -125,32 +129,52 @@ bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_H
<row>
<entry>__u32</entry>
<entry><structfield>vfrontporch</structfield></entry>
<entry>Vertical front porch in lines</entry>
<entry>Vertical front porch in lines. For interlaced formats this refers to the
odd field (aka field 1).</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>vsync</structfield></entry>
<entry>Vertical sync length in lines</entry>
<entry>Vertical sync length in lines. For interlaced formats this refers to the
odd field (aka field 1).</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>vbackporch</structfield></entry>
<entry>Vertical back porch in lines</entry>
<entry>Vertical back porch in lines. For interlaced formats this refers to the
odd field (aka field 1).</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>il_vfrontporch</structfield></entry>
<entry>Vertical front porch in lines for bottom field of interlaced field formats</entry>
<entry>Vertical front porch in lines for the even field (aka field 2) of
interlaced field formats.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>il_vsync</structfield></entry>
<entry>Vertical sync length in lines for bottom field of interlaced field formats</entry>
<entry>Vertical sync length in lines for the even field (aka field 2) of
interlaced field formats.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>il_vbackporch</structfield></entry>
<entry>Vertical back porch in lines for bottom field of interlaced field formats</entry>
<entry>Vertical back porch in lines for the even field (aka field 2) of
interlaced field formats.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>standards</structfield></entry>
<entry>The video standard(s) this format belongs to. This will be filled in by
the driver. Applications must set this to 0. See <xref linkend="dv-bt-standards"/>
for a list of standards.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>flags</structfield></entry>
<entry>Several flags giving more information about the format.
See <xref linkend="dv-bt-flags"/> for a description of the flags.
</entry>
</row>
</tbody>
</tgroup>
......@@ -211,6 +235,90 @@ bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_H
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="dv-bt-standards">
<title>DV BT Timing standards</title>
<tgroup cols="2">
&cs-str;
<tbody valign="top">
<row>
<entry>Timing standard</entry>
<entry>Description</entry>
</row>
<row>
<entry></entry>
<entry></entry>
</row>
<row>
<entry>V4L2_DV_BT_STD_CEA861</entry>
<entry>The timings follow the CEA-861 Digital TV Profile standard</entry>
</row>
<row>
<entry>V4L2_DV_BT_STD_DMT</entry>
<entry>The timings follow the VESA Discrete Monitor Timings standard</entry>
</row>
<row>
<entry>V4L2_DV_BT_STD_CVT</entry>
<entry>The timings follow the VESA Coordinated Video Timings standard</entry>
</row>
<row>
<entry>V4L2_DV_BT_STD_GTF</entry>
<entry>The timings follow the VESA Generalized Timings Formula standard</entry>
</row>
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="dv-bt-flags">
<title>DV BT Timing flags</title>
<tgroup cols="2">
&cs-str;
<tbody valign="top">
<row>
<entry>Flag</entry>
<entry>Description</entry>
</row>
<row>
<entry></entry>
<entry></entry>
</row>
<row>
<entry>V4L2_DV_FL_REDUCED_BLANKING</entry>
<entry>CVT/GTF specific: the timings use reduced blanking (CVT) or the 'Secondary
GTF' curve (GTF). In both cases the horizontal and/or vertical blanking
intervals are reduced, allowing a higher resolution over the same
bandwidth. This is a read-only flag, applications must not set this.
</entry>
</row>
<row>
<entry>V4L2_DV_FL_CAN_REDUCE_FPS</entry>
<entry>CEA-861 specific: set for CEA-861 formats with a framerate that is a multiple
of six. These formats can be optionally played at 1 / 1.001 speed to
be compatible with 60 Hz based standards such as NTSC and PAL-M that use a framerate of
29.97 frames per second. If the transmitter can't generate such frequencies, then the
flag will also be cleared. This is a read-only flag, applications must not set this.
</entry>
</row>
<row>
<entry>V4L2_DV_FL_REDUCED_FPS</entry>
<entry>CEA-861 specific: only valid for video transmitters, the flag is cleared
by receivers. It is also only valid for formats with the V4L2_DV_FL_CAN_REDUCE_FPS flag
set, for other formats the flag will be cleared by the driver.
If the application sets this flag, then the pixelclock used to set up the transmitter is
divided by 1.001 to make it compatible with NTSC framerates. If the transmitter
can't generate such frequencies, then the flag will also be cleared.
</entry>
</row>
<row>
<entry>V4L2_DV_FL_HALF_LINE</entry>
<entry>Specific to interlaced formats: if set, then field 1 (aka the odd field)
is really one half-line longer and field 2 (aka the even field) is really one half-line
shorter, so each field has exactly the same number of half-lines. Whether half-lines can be
detected or used depends on the hardware.
</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
<refsect1>
&return-value;
......
Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml
View file @ 7dcc606b
......@@ -48,6 +48,12 @@
<refsect1>
<title>Description</title>
<note>
<title>Experimental</title>
<para>This is an <link linkend="experimental"> experimental </link>
interface and may change in the future.</para>
</note>
<para>Applications can optionally call the
<constant>VIDIOC_PREPARE_BUF</constant> ioctl to pass ownership of the buffer
to the driver before actually enqueuing it, using the
......
Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml 0 → 100644
View file @ 7dcc606b
<refentry id="vidioc-query-dv-timings">
<refmeta>
<refentrytitle>ioctl VIDIOC_QUERY_DV_TIMINGS</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_QUERY_DV_TIMINGS</refname>
<refpurpose>Sense the DV preset received by the current
input</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_dv_timings *<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_QUERY_DV_TIMINGS</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<note>
<title>Experimental</title>
<para>This is an <link linkend="experimental"> experimental </link>
interface and may change in the future.</para>
</note>
<para>The hardware may be able to detect the current DV timings
automatically, similar to sensing the video standard. To do so, applications
call <constant>VIDIOC_QUERY_DV_TIMINGS</constant> with a pointer to a
&v4l2-dv-timings;. Once the hardware detects the timings, it will fill in the
timings structure.
If the timings could not be detected because there was no signal, then
<errorcode>ENOLINK</errorcode> is returned. If a signal was detected, but
it was unstable and the receiver could not lock to the signal, then
<errorcode>ENOLCK</errorcode> is returned. If the receiver could lock to the signal,
but the format is unsupported (e.g. because the pixelclock is out of range
of the hardware capabilities), then the driver fills in whatever timings it
could find and returns <errorcode>ERANGE</errorcode>. In that case the application
can call &VIDIOC-DV-TIMINGS-CAP; to compare the found timings with the hardware's
capabilities in order to give more precise feedback to the user.
</para>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>ENOLINK</errorcode></term>
<listitem>
<para>No timings could be detected because no signal was found.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENOLCK</errorcode></term>
<listitem>
<para>The signal was unstable and the hardware could not lock on to it.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ERANGE</errorcode></term>
<listitem>
<para>Timings were found, but they are out of range of the hardware
capabilities.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7