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.
89     * - __u32
90       - ``type``
91       - Type of the data stream, set by the application. Only these types
102     * - __u32
103       - ``flags``
104       - See :ref:`fmtdesc-flags`
105     * - __u8
106       - ``description``\ [32]
107       - Description of the format, a NUL-terminated ASCII string. This
109     * - __u32
110       - ``pixelformat``
111       - The image format identifier. This is a four character code as
113     * - :cspan:`2`
115 	.. _v4l2-fourcc:
121 	Several image formats are already defined by this specification in
127 	   in the Windows world.
128     * - __u32
129       - ``mbus_code``
130       - Media bus code restricting the enumerated formats, set by the
131         application. Only applicable to drivers that advertise the
132         ``V4L2_CAP_IO_MC`` :ref:`capability <device-capabilities>`, shall be 0
134     * - __u32
135       - ``reserved``\ [3]
136       - Reserved for future extensions. Drivers must set the array to
144 .. _fmtdesc-flags:
146 .. flat-table:: Image Format Description Flags
147     :header-rows:  0
148     :stub-columns: 0
151     * - ``V4L2_FMT_FLAG_COMPRESSED``
152       - 0x0001
153       - This is a compressed format.
154     * - ``V4L2_FMT_FLAG_EMULATED``
155       - 0x0002
156       - This format is not native to the device but emulated through
159     * - ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
160       - 0x0004
161       - The hardware decoder for this compressed bytestream format (aka coded
166 	This flag can only be used in combination with the
169     * - ``V4L2_FMT_FLAG_DYN_RESOLUTION``
170       - 0x0008
171       - Dynamic resolution switching is supported by the device for this
173 	via the event ``V4L2_EVENT_SOURCE_CHANGE`` when changes in the video
176 	This flag can only be used in combination with the
179     * - ``V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL``
180       - 0x0010
181       - The hardware encoder supports setting the ``CAPTURE`` coded frame
189 	frame interval is the actual frame rate embedded in the encoded video
192 	This flag can only be used in combination with the
195     * - ``V4L2_FMT_FLAG_CSC_COLORSPACE``
196       - 0x0020
197       - The driver allows the application to try to change the default
199 	The application can ask to configure the colorspace of the capture device
201 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
202     * - ``V4L2_FMT_FLAG_CSC_XFER_FUNC``
203       - 0x0040
204       - The driver allows the application to try to change the default
206 	The application can ask to configure the transfer function of the capture
208 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
209     * - ``V4L2_FMT_FLAG_CSC_YCBCR_ENC``
210       - 0x0080
211       - The driver allows the application to try to change the default
213 	The application can ask to configure the Y'CbCr encoding of the capture device
215 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
216     * - ``V4L2_FMT_FLAG_CSC_HSV_ENC``
217       - 0x0080
218       - The driver allows the application to try to change the default
220 	The application can ask to configure the HSV encoding of the capture device
222 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
223     * - ``V4L2_FMT_FLAG_CSC_QUANTIZATION``
224       - 0x0100
225       - The driver allows the application to try to change the default
227 	The application can ask to configure the quantization of the capture
229 	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
234 On success 0 is returned, on error -1 and the ``errno`` variable is set
236 :ref:`Generic Error Codes <gen-errors>` chapter.