diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 259 |
1 files changed, 0 insertions, 259 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml deleted file mode 100644 index 73eb5cfe698a..000000000000 --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml +++ /dev/null @@ -1,259 +0,0 @@ -<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> - - <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>() or &VIDIOC-STREAMON; call sends an implicit -START command to the decoder if it has not been started yet. -</para> - - <para>A <function>close</function>() or &VIDIOC-STREAMOFF; call of a streaming -file descriptor sends an implicit immediate STOP command 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>__s32</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 will just change the playback speed. -That means that calling <constant>V4L2_DEC_CMD_START</constant> when -the decoder was paused will <emphasis>not</emphasis> resume the decoder. -You have to explicitly call <constant>V4L2_DEC_CMD_RESUME</constant> for that. -This command has one flag: -<constant>V4L2_DEC_CMD_START_MUTE_AUDIO</constant>. If set, then audio will -be muted when playing back at a non-standard speed. - </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. mem2mem decoders will stop producing new frames altogether. They will send -a <constant>V4L2_EVENT_EOS</constant> event when the last frame has been decoded -and all frames are ready to be dequeued and will set the -<constant>V4L2_BUF_FLAG_LAST</constant> buffer flag on the last buffer of the -capture queue to indicate there will be no new buffers produced to dequeue. This -buffer may be empty, indicated by the driver setting the -<structfield>bytesused</structfield> field to 0. Once the -<constant>V4L2_BUF_FLAG_LAST</constant> flag was set, the -<link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl will not block anymore, -but return an &EPIPE;. -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> |