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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
commitc720f5655df159a630fa0290a0bd67c93e92b0bf (patch)
tree940d139d0ec1ff5201efddef6cc663166a8a2df3 /Documentation/DocBook/v4l/vidioc-g-enc-index.xml
parent33e6c1a0de818d3698cdab27c42915661011319d (diff)
parent84d6ae431f315e8973aac3c3fe1d550fc9240ef3 (diff)
downloadtalos-obmc-linux-c720f5655df159a630fa0290a0bd67c93e92b0bf.tar.gz
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Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (222 commits) V4L/DVB (13033): pt1: Don't use a deprecated DMA_BIT_MASK macro V4L/DVB (13029): radio-si4713: remove #include <linux/version.h> V4L/DVB (13027): go7007: convert printks to v4l2_info V4L/DVB (13026): s2250-board: Implement brightness and contrast controls V4L/DVB (13025): s2250-board: Fix memory leaks V4L/DVB (13024): go7007: Implement vidioc_g_std and vidioc_querystd V4L/DVB (13023): go7007: Merge struct gofh and go declarations V4L/DVB (13022): go7007: Fix mpeg controls V4L/DVB (13021): go7007: Fix whitespace and line lengths V4L/DVB (13020): go7007: Updates to Kconfig and Makefile V4L/DVB (13019): video: initial support for ADV7180 V4L/DVB (13018): kzalloc failure ignored in au8522_probe() V4L/DVB (13017): gspca: kmalloc failure ignored in sd_start() V4L/DVB (13016): kmalloc failure ignored in lgdt3304_attach() and s921_attach() V4L/DVB (13015): kmalloc failure ignored in m920x_firmware_download() V4L/DVB (13014): Add support for Compro VideoMate E800 (DVB-T part only) V4L/DVB (13013): FM TX: si4713: Kconfig: Fixed two typos. V4L/DVB (13012): uvc: introduce missing kfree V4L/DVB (13011): Change tuner type of BeholdTV cards V4L/DVB (13009): gspca - stv06xx-hdcs: Reduce exposure range ...
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+<refentry id="vidioc-g-enc-index">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_G_ENC_INDEX</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_G_ENC_INDEX</refname>
+ <refpurpose>Get meta data about a compressed video stream</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_enc_idx *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>fd</parameter></term>
+ <listitem>
+ <para>&fd;</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>request</parameter></term>
+ <listitem>
+ <para>VIDIOC_G_ENC_INDEX</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 <constant>VIDIOC_G_ENC_INDEX</constant> ioctl provides
+meta data about a compressed video stream the same or another
+application currently reads from the driver, which is useful for
+random access into the stream without decoding it.</para>
+
+ <para>To read the data applications must call
+<constant>VIDIOC_G_ENC_INDEX</constant> with a pointer to a
+&v4l2-enc-idx;. On success the driver fills the
+<structfield>entry</structfield> array, stores the number of elements
+written in the <structfield>entries</structfield> field, and
+initializes the <structfield>entries_cap</structfield> field.</para>
+
+ <para>Each element of the <structfield>entry</structfield> array
+contains meta data about one picture. A
+<constant>VIDIOC_G_ENC_INDEX</constant> call reads up to
+<constant>V4L2_ENC_IDX_ENTRIES</constant> entries from a driver
+buffer, which can hold up to <structfield>entries_cap</structfield>
+entries. This number can be lower or higher than
+<constant>V4L2_ENC_IDX_ENTRIES</constant>, but not zero. When the
+application fails to read the meta data in time the oldest entries
+will be lost. When the buffer is empty or no capturing/encoding is in
+progress, <structfield>entries</structfield> will be zero.</para>
+
+ <para>Currently this ioctl is only defined for MPEG-2 program
+streams and video elementary streams.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-enc-idx">
+ <title>struct <structname>v4l2_enc_idx</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>entries</structfield></entry>
+ <entry>The number of entries the driver stored in the
+<structfield>entry</structfield> array.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>entries_cap</structfield></entry>
+ <entry>The number of entries the driver can
+buffer. Must be greater than zero.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[4]</entry>
+ <entry spanname="hspan">Reserved for future extensions.
+Drivers must set the array to zero.</entry>
+ </row>
+ <row>
+ <entry>&v4l2-enc-idx-entry;</entry>
+ <entry><structfield>entry</structfield>[<constant>V4L2_ENC_IDX_ENTRIES</constant>]</entry>
+ <entry>Meta data about a compressed video stream. Each
+element of the array corresponds to one picture, sorted in ascending
+order by their <structfield>offset</structfield>.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="v4l2-enc-idx-entry">
+ <title>struct <structname>v4l2_enc_idx_entry</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u64</entry>
+ <entry><structfield>offset</structfield></entry>
+ <entry>The offset in bytes from the beginning of the
+compressed video stream to the beginning of this picture, that is a
+<wordasword>PES packet header</wordasword> as defined in <xref
+ linkend="mpeg2part1" /> or a <wordasword>picture
+header</wordasword> as defined in <xref linkend="mpeg2part2" />. When
+the encoder is stopped, the driver resets the offset to zero.</entry>
+ </row>
+ <row>
+ <entry>__u64</entry>
+ <entry><structfield>pts</structfield></entry>
+ <entry>The 33 bit <wordasword>Presentation Time
+Stamp</wordasword> of this picture as defined in <xref
+ linkend="mpeg2part1" />.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>length</structfield></entry>
+ <entry>The length of this picture in bytes.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>flags</structfield></entry>
+ <entry>Flags containing the coding type of this picture, see <xref
+ linkend="enc-idx-flags" />.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[2]</entry>
+ <entry>Reserved for future extensions.
+Drivers must set the array to zero.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="enc-idx-flags">
+ <title>Index Entry Flags</title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_ENC_IDX_FRAME_I</constant></entry>
+ <entry>0x00</entry>
+ <entry>This is an Intra-coded picture.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_ENC_IDX_FRAME_P</constant></entry>
+ <entry>0x01</entry>
+ <entry>This is a Predictive-coded picture.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_ENC_IDX_FRAME_B</constant></entry>
+ <entry>0x02</entry>
+ <entry>This is a Bidirectionally predictive-coded
+picture.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_ENC_IDX_FRAME_MASK</constant></entry>
+ <entry>0x0F</entry>
+ <entry><wordasword>AND</wordasword> the flags field with
+this mask to obtain the picture coding type.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The driver does not support this ioctl.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->
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