media/v4l/vidioc-decoder-cmd.rst

1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 VIDIOC_DECODER_CMD - VIDIOC_TRY_DECODER_CMD - Execute an decoder command
38 These ioctls control an audio/video (usually MPEG-) decoder.
55 command to the decoder, and all buffered data is discarded. Applies to both
68 .. flat-table:: struct v4l2_decoder_cmd
69     :header-rows:  0
70     :stub-columns: 0
73     * - __u32
74       - ``cmd``
75       -
76       - The decoder command, see :ref:`decoder-cmds`.
77     * - __u32
78       - ``flags``
79       -
80       - Flags to go with the command. If no flags are defined for this
82     * - union {
83       - (anonymous)
84     * - struct
85       - ``start``
86       -
87       - Structure containing additional data for the
89     * -
90       - __s32
91       - ``speed``
92       - Playback speed and direction. The playback speed is defined as
94 	Negative numbers denote reverse playback, so -1000 does reverse
95 	playback at normal speed. Speeds -1, 0 and 1 have special
97 	of 1 steps just one frame forward, a speed of -1 steps just one
99     * -
100       - __u32
101       - ``format``
102       - Format restrictions. This field is set by the driver, not the
110     * - struct
111       - ``stop``
112       -
113       - Structure containing additional data for the ``V4L2_DEC_CMD_STOP``
115     * -
116       - __u64
117       - ``pts``
118       - Stop playback at this ``pts`` or immediately if the playback is
121     * - struct
122       - ``raw``
123     * -
124       - __u32
125       - ``data``\ [16]
126       - Reserved for future extensions. Drivers and applications must set
128     * - }
129       -
136 .. _decoder-cmds:
138 .. flat-table:: Decoder Commands
139     :header-rows:  0
140     :stub-columns: 0
143     * - ``V4L2_DEC_CMD_START``
144       - 0
145       - Start the decoder. When the decoder is already running or paused,
151 	muted when playing back at a non-standard speed.
161     * - ``V4L2_DEC_CMD_STOP``
162       - 1
163       - Stop the decoder. When the decoder is already stopped, this
178     * - ``V4L2_DEC_CMD_PAUSE``
179       - 2
180       - Pause the decoder. When the decoder has not been started yet, the
185     * - ``V4L2_DEC_CMD_RESUME``
186       - 3
187       - Resume decoding after a PAUSE command. When the decoder has not
191     * - ``V4L2_DEC_CMD_FLUSH``
192       - 4
193       - Flush any held capture buffers. Only valid for stateless decoders.
204 On success 0 is returned, on error -1 and the ``errno`` variable is set
206 :ref:`Generic Error Codes <gen-errors>` chapter.