media/v4l/vidioc-enum-fmt.rst

1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 VIDIOC_ENUM_FMT - Enumerate image formats
40 formats in preference order, where preferred formats are returned before
41 (that is, with lower ``index`` value) less-preferred formats.
43 Depending on the ``V4L2_CAP_IO_MC`` :ref:`capability <device-capabilities>`,
46 1) ``V4L2_CAP_IO_MC`` is not set (also known as a 'video-node-centric' driver)
58 2) ``V4L2_CAP_IO_MC`` is set (also known as an 'MC-centric' driver)
63    If the ``mbus_code`` field is initialized to a valid (non-zero)
64    :ref:`media bus format code <v4l2-mbus-pixelcode>`, then drivers
80 .. flat-table:: struct v4l2_fmtdesc
81     :header-rows:  0
82     :stub-columns: 0
85     * - __u32
86       - ``index``
87       - Number of the format in the enumeration, set by the application.
88         This is in no way related to the ``pixelformat`` field.
99     * - __u32
100       - ``type``
101       - Type of the data stream, set by the application. Only these types
112     * - __u32
113       - ``flags``
114       - See :ref:`fmtdesc-flags`
115     * - __u8
116       - ``description``\ [32]
117       - Description of the format, a NUL-terminated ASCII string. This
119     * - __u32
120       - ``pixelformat``
121       - The image format identifier. This is a four character code as
123     * - :cspan:`2`
125 	.. _v4l2-fourcc:
131 	Several image formats are already defined by this specification in
137 	   in the Windows world.
138     * - __u32
139       - ``mbus_code``
140       - Media bus code restricting the enumerated formats, set by the
141         application. Only applicable to drivers that advertise the
142         ``V4L2_CAP_IO_MC`` :ref:`capability <device-capabilities>`, shall be 0
144     * - __u32
145       - ``reserved``\ [3]
146       - Reserved for future extensions. Drivers must set the array to
154 .. _fmtdesc-flags:
156 .. flat-table:: Image Format Description Flags
157     :header-rows:  0
158     :stub-columns: 0
161     * - ``V4L2_FMT_FLAG_COMPRESSED``
162       - 0x0001
163       - This is a compressed format.
164     * - ``V4L2_FMT_FLAG_EMULATED``
165       - 0x0002
166       - This format is not native to the device but emulated through
169     * - ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
170       - 0x0004
171       - The hardware decoder for this compressed bytestream format (aka coded
176 	This flag can only be used in combination with the
179     * - ``V4L2_FMT_FLAG_DYN_RESOLUTION``
180       - 0x0008
181       - Dynamic resolution switching is supported by the device for this
183 	via the event ``V4L2_EVENT_SOURCE_CHANGE`` when changes in the video
186 	This flag can only be used in combination with the
189     * - ``V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL``
190       - 0x0010
191       - The hardware encoder supports setting the ``CAPTURE`` coded frame
199 	frame interval is the actual frame rate embedded in the encoded video
202 	This flag can only be used in combination with the
205     * - ``V4L2_FMT_FLAG_CSC_COLORSPACE``
206       - 0x0020
207       - The driver allows the application to try to change the default
209 	The application can ask to configure the colorspace of the capture device
211 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
212     * - ``V4L2_FMT_FLAG_CSC_XFER_FUNC``
213       - 0x0040
214       - The driver allows the application to try to change the default
216 	The application can ask to configure the transfer function of the capture
218 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
219     * - ``V4L2_FMT_FLAG_CSC_YCBCR_ENC``
220       - 0x0080
221       - The driver allows the application to try to change the default
223 	The application can ask to configure the Y'CbCr encoding of the capture device
225 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
226     * - ``V4L2_FMT_FLAG_CSC_HSV_ENC``
227       - 0x0080
228       - The driver allows the application to try to change the default
230 	The application can ask to configure the HSV encoding of the capture device
232 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
233     * - ``V4L2_FMT_FLAG_CSC_QUANTIZATION``
234       - 0x0100
235       - The driver allows the application to try to change the default
237 	The application can ask to configure the quantization of the capture
239 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
240     * - ``V4L2_FMT_FLAG_META_LINE_BASED``
241       - 0x0200
242       - The metadata format is line-based. In this case the ``width``,
245 	Data Units of data and the offset (in bytes) between the beginning of
247     * - ``V4L2_FMTDESC_FLAG_ENUM_ALL``
248       - 0x80000000
249       - When the applications ORs ``index`` with ``V4L2_FMTDESC_FLAG_ENUM_ALL`` flag
257 On success 0 is returned, on error -1 and the ``errno`` variable is set
259 :ref:`Generic Error Codes <gen-errors>` chapter.