From: Hans Verkuil <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
---
Documentation/DocBook/media/v4l/v4l2.xml | 1 +
.../DocBook/media/v4l/vidioc-decoder-cmd.xml | 250 ++++++++++++++++++++
2 files changed, 251 insertions(+), 0 deletions(-)
create mode 100644 Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml
b/Documentation/DocBook/media/v4l/v4l2.xml
index 2ab365c..7fc11db 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -473,6 +473,7 @@ and discussions on the V4L mailing list.</revremark>
&sub-cropcap;
&sub-dbg-g-chip-ident;
&sub-dbg-g-register;
+ &sub-decoder-cmd;
&sub-dqevent;
&sub-encoder-cmd;
&sub-enumaudio;
diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
new file mode 100644
index 0000000..bf016f0
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml
@@ -0,0 +1,250 @@
+<refentry id="vidioc-decoder-cmd">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_DECODER_CMD,
VIDIOC_TRY_DECODER_CMD</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_DECODER_CMD</refname>
+ <refname>VIDIOC_TRY_DECODER_CMD</refname>
+ <refpurpose>Execute an decoder command</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_decoder_cmd
*<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_DECODER_CMD, VIDIOC_TRY_DECODER_CMD</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>These ioctls control an audio/video (usually MPEG-) decoder.
+<constant>VIDIOC_DECODER_CMD</constant> sends a command to the
+decoder, <constant>VIDIOC_TRY_DECODER_CMD</constant> can be used to
+try a command without actually executing it. To send a command applications
+must initialize all fields of a &v4l2-decoder-cmd; and call
+<constant>VIDIOC_DECODER_CMD</constant> or
<constant>VIDIOC_TRY_DECODER_CMD</constant>
+with a pointer to this structure.</para>
+
+ <para>The <structfield>cmd</structfield> field must contain the
+command code. Some commands use the <structfield>flags</structfield> field for
+additional information.
+</para>
+
+ <para>A <function>write</function>() call sends a START command to
+the decoder if it has not been started yet.
+</para>
+
+ <para>A <function>close</function>() call sends an immediate STOP
+to the decoder, and all buffered data is discarded.</para>
+
+ <para>These ioctls are optional, not all drivers may support
+them. They were introduced in Linux 3.3.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-decoder-cmd">
+ <title>struct <structname>v4l2_decoder_cmd</structname></title>
+ <tgroup cols="5">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>cmd</structfield></entry>
+ <entry></entry>
+ <entry></entry>
+ <entry>The decoder command, see <xref linkend="decoder-cmds"
/>.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>flags</structfield></entry>
+ <entry></entry>
+ <entry></entry>
+ <entry>Flags to go with the command. If no flags are defined for
+this command, drivers and applications must set this field to zero.</entry>
+ </row>
+ <row>
+ <entry>union</entry>
+ <entry>(anonymous)</entry>
+ <entry></entry>
+ <entry></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry>struct</entry>
+ <entry><structfield>start</structfield></entry>
+ <entry></entry>
+ <entry>Structure containing additional data for the
+<constant>V4L2_DEC_CMD_START</constant> command.</entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry></entry>
+ <entry>__u32</entry>
+ <entry><structfield>speed</structfield></entry>
+ <entry>Playback speed and direction. The playback speed is defined
as
+<structfield>speed</structfield>/1000 of the normal speed. So 1000 is normal
playback.
+Negative numbers denote reverse playback, so -1000 does reverse playback at
normal
+speed. Speeds -1, 0 and 1 have special meanings: speed 0 is shorthand for 1000
+(normal playback). A speed of 1 steps just one frame forward, a speed of -1
steps
+just one frame back.
+ </entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry></entry>
+ <entry>__u32</entry>
+ <entry><structfield>format</structfield></entry>
+ <entry>Format restrictions. This field is set by the driver, not
the
+application. Possible values are <constant>V4L2_DEC_START_FMT_NONE</constant>
if
+there are no format restrictions or <constant>V4L2_DEC_START_FMT_GOP</constant>
+if the decoder operates on full GOPs (<wordasword>Group Of
Pictures</wordasword>).
+This is usually the case for reverse playback: the decoder needs full GOPs,
which
+it can then play in reverse order. So to implement reverse playback the
application
+must feed the decoder the last GOP in the video file, then the GOP before
that, etc. etc.
+ </entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry>struct</entry>
+ <entry><structfield>stop</structfield></entry>
+ <entry></entry>
+ <entry>Structure containing additional data for the
+<constant>V4L2_DEC_CMD_STOP</constant> command.</entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry></entry>
+ <entry>__u64</entry>
+ <entry><structfield>pts</structfield></entry>
+ <entry>Stop playback at this <structfield>pts</structfield> or
immediately
+if the playback is already past that timestamp. Leave to 0 if you want to stop
after the
+last frame was decoded.
+ </entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry>struct</entry>
+ <entry><structfield>raw</structfield></entry>
+ <entry></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry></entry>
+ <entry>__u32</entry>
+ <entry><structfield>data</structfield>[16]</entry>
+ <entry>Reserved for future extensions. Drivers and
+applications must set the array to zero.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="decoder-cmds">
+ <title>Decoder Commands</title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_DEC_CMD_START</constant></entry>
+ <entry>0</entry>
+ <entry>Start the decoder. When the decoder is already
+running or paused, this command does nothing. There are no flags
+associated with this command.
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_DEC_CMD_STOP</constant></entry>
+ <entry>1</entry>
+ <entry>Stop the decoder. When the decoder is already stopped,
+this command does nothing. This command has two flags:
+if <constant>V4L2_DEC_CMD_STOP_TO_BLACK</constant> is set, then the decoder
will
+set the picture to black after it stopped decoding. Otherwise the last image
will
+repeat. If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the
decoder
+stops immediately (ignoring the <structfield>pts</structfield> value),
otherwise it
+will keep decoding until timestamp >= pts or until the last of the pending
data from
+its internal buffers was decoded.
+</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_DEC_CMD_PAUSE</constant></entry>
+ <entry>2</entry>
+ <entry>Pause the decoder. When the decoder has not been
+started yet, the driver will return an &EPERM;. When the decoder is
+already paused, this command does nothing. This command has one flag:
+if <constant>V4L2_DEC_CMD_PAUSE_TO_BLACK</constant> is set, then set the
+decoder output to black when paused.
+</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_DEC_CMD_RESUME</constant></entry>
+ <entry>3</entry>
+ <entry>Resume decoding after a PAUSE command. When the
+decoder has not been started yet, the driver will return an &EPERM;.
+When the decoder is already running, this command does nothing. No
+flags are defined for this command.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The <structfield>cmd</structfield> field is invalid.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>EPERM</errorcode></term>
+ <listitem>
+ <para>The application sent a PAUSE or RESUME command when
+the decoder was not running.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
--
1.7.7.3
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