doc-rst: linux_tv DocBook to reST migration (docs-next)
This is the restructuredText (reST) migration of the ``media``
DocBook-XML set from the linux_tv project.
Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/linux_tv/media/v4l/vidioc-decoder-cmd.rst b/Documentation/linux_tv/media/v4l/vidioc-decoder-cmd.rst
new file mode 100644
index 0000000..77c7bdf
--- /dev/null
+++ b/Documentation/linux_tv/media/v4l/vidioc-decoder-cmd.rst
@@ -0,0 +1,280 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _vidioc-decoder-cmd:
+
+************************************************
+ioctl VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD
+************************************************
+
+*man VIDIOC_DECODER_CMD(2)*
+
+VIDIOC_TRY_DECODER_CMD
+Execute an decoder command
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, int request, struct v4l2_decoder_cmd *argp )
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+ VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD
+
+``argp``
+
+
+Description
+===========
+
+These ioctls control an audio/video (usually MPEG-) decoder.
+``VIDIOC_DECODER_CMD`` sends a command to the decoder,
+``VIDIOC_TRY_DECODER_CMD`` can be used to try a command without actually
+executing it. To send a command applications must initialize all fields
+of a struct :ref:`v4l2_decoder_cmd <v4l2-decoder-cmd>` and call
+``VIDIOC_DECODER_CMD`` or ``VIDIOC_TRY_DECODER_CMD`` with a pointer to
+this structure.
+
+The ``cmd`` field must contain the command code. Some commands use the
+``flags`` field for additional information.
+
+A :c:func:`write()`() or :ref:`VIDIOC_STREAMON <vidioc-streamon>`
+call sends an implicit START command to the decoder if it has not been
+started yet.
+
+A :c:func:`close()`() or :ref:`VIDIOC_STREAMOFF <vidioc-streamon>`
+call of a streaming file descriptor sends an implicit immediate STOP
+command to the decoder, and all buffered data is discarded.
+
+These ioctls are optional, not all drivers may support them. They were
+introduced in Linux 3.3.
+
+
+.. _v4l2-decoder-cmd:
+
+.. flat-table:: struct v4l2_decoder_cmd
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2 1 1
+
+
+ - .. row 1
+
+ - __u32
+
+ - ``cmd``
+
+ -
+ -
+ - The decoder command, see :ref:`decoder-cmds`.
+
+ - .. row 2
+
+ - __u32
+
+ - ``flags``
+
+ -
+ -
+ - Flags to go with the command. If no flags are defined for this
+ command, drivers and applications must set this field to zero.
+
+ - .. row 3
+
+ - union
+
+ - (anonymous)
+
+ -
+ -
+ -
+
+ - .. row 4
+
+ -
+ - struct
+
+ - ``start``
+
+ -
+ - Structure containing additional data for the
+ ``V4L2_DEC_CMD_START`` command.
+
+ - .. row 5
+
+ -
+ -
+ - __s32
+
+ - ``speed``
+
+ - Playback speed and direction. The playback speed is defined as
+ ``speed``/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.
+
+ - .. row 6
+
+ -
+ -
+ - __u32
+
+ - ``format``
+
+ - Format restrictions. This field is set by the driver, not the
+ application. Possible values are ``V4L2_DEC_START_FMT_NONE`` if
+ there are no format restrictions or ``V4L2_DEC_START_FMT_GOP`` if
+ the decoder operates on full GOPs (*Group Of Pictures*). 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.
+
+ - .. row 7
+
+ -
+ - struct
+
+ - ``stop``
+
+ -
+ - Structure containing additional data for the ``V4L2_DEC_CMD_STOP``
+ command.
+
+ - .. row 8
+
+ -
+ -
+ - __u64
+
+ - ``pts``
+
+ - Stop playback at this ``pts`` or immediately if the playback is
+ already past that timestamp. Leave to 0 if you want to stop after
+ the last frame was decoded.
+
+ - .. row 9
+
+ -
+ - struct
+
+ - ``raw``
+
+ -
+ -
+
+ - .. row 10
+
+ -
+ -
+ - __u32
+
+ - ``data``\ [16]
+
+ - Reserved for future extensions. Drivers and applications must set
+ the array to zero.
+
+
+
+.. _decoder-cmds:
+
+.. flat-table:: Decoder Commands
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 3 1 4
+
+
+ - .. row 1
+
+ - ``V4L2_DEC_CMD_START``
+
+ - 0
+
+ - Start the decoder. When the decoder is already running or paused,
+ this command will just change the playback speed. That means that
+ calling ``V4L2_DEC_CMD_START`` when the decoder was paused will
+ *not* resume the decoder. You have to explicitly call
+ ``V4L2_DEC_CMD_RESUME`` for that. This command has one flag:
+ ``V4L2_DEC_CMD_START_MUTE_AUDIO``. If set, then audio will be
+ muted when playing back at a non-standard speed.
+
+ - .. row 2
+
+ - ``V4L2_DEC_CMD_STOP``
+
+ - 1
+
+ - Stop the decoder. When the decoder is already stopped, this
+ command does nothing. This command has two flags: if
+ ``V4L2_DEC_CMD_STOP_TO_BLACK`` 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 ``V4L2_EVENT_EOS`` event when the
+ last frame has been decoded and all frames are ready to be
+ dequeued and will set the ``V4L2_BUF_FLAG_LAST`` 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 ``bytesused`` field to 0. Once
+ the ``V4L2_BUF_FLAG_LAST`` flag was set, the
+ :ref:`VIDIOC_DQBUF <vidioc-qbuf>` ioctl will not block anymore,
+ but return an EPIPE error code. If
+ ``V4L2_DEC_CMD_STOP_IMMEDIATELY`` is set, then the decoder stops
+ immediately (ignoring the ``pts`` value), otherwise it will keep
+ decoding until timestamp >= pts or until the last of the pending
+ data from its internal buffers was decoded.
+
+ - .. row 3
+
+ - ``V4L2_DEC_CMD_PAUSE``
+
+ - 2
+
+ - Pause the decoder. When the decoder has not been started yet, the
+ driver will return an EPERM error code. When the decoder is
+ already paused, this command does nothing. This command has one
+ flag: if ``V4L2_DEC_CMD_PAUSE_TO_BLACK`` is set, then set the
+ decoder output to black when paused.
+
+ - .. row 4
+
+ - ``V4L2_DEC_CMD_RESUME``
+
+ - 3
+
+ - Resume decoding after a PAUSE command. When the decoder has not
+ been started yet, the driver will return an EPERM error code. When
+ the decoder is already running, this command does nothing. No
+ flags are defined for this command.
+
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EINVAL
+ The ``cmd`` field is invalid.
+
+EPERM
+ The application sent a PAUSE or RESUME command when the decoder was
+ not running.
+
+
+.. ------------------------------------------------------------------------------
+.. This file was automatically converted from DocBook-XML with the dbxml
+.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
+.. from the linux kernel, refer to:
+..
+.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
+.. ------------------------------------------------------------------------------