1.. Permission is granted to copy, distribute and/or modify this 2.. document under the terms of the GNU Free Documentation License, 3.. Version 1.1 or any later version published by the Free Software 4.. Foundation, with no Invariant Sections, no Front-Cover Texts 5.. and no Back-Cover Texts. A copy of the license is included at 6.. Documentation/userspace-api/media/fdl-appendix.rst. 7.. 8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections 9 10.. _VIDIOC_ENUM_FRAMESIZES: 11 12**************************** 13ioctl VIDIOC_ENUM_FRAMESIZES 14**************************** 15 16Name 17==== 18 19VIDIOC_ENUM_FRAMESIZES - Enumerate frame sizes 20 21 22Synopsis 23======== 24 25.. c:function:: int ioctl( int fd, VIDIOC_ENUM_FRAMESIZES, struct v4l2_frmsizeenum *argp ) 26 :name: VIDIOC_ENUM_FRAMESIZES 27 28 29Arguments 30========= 31 32``fd`` 33 File descriptor returned by :ref:`open() <func-open>`. 34 35``argp`` 36 Pointer to struct :c:type:`v4l2_frmsizeenum` 37 that contains an index and pixel format and receives a frame width 38 and height. 39 40 41Description 42=========== 43 44This ioctl allows applications to enumerate all frame sizes (i. e. width 45and height in pixels) that the device supports for the given pixel 46format. 47 48The supported pixel formats can be obtained by using the 49:ref:`VIDIOC_ENUM_FMT` function. 50 51The return value and the content of the ``v4l2_frmsizeenum.type`` field 52depend on the type of frame sizes the device supports. Here are the 53semantics of the function for the different cases: 54 55- **Discrete:** The function returns success if the given index value 56 (zero-based) is valid. The application should increase the index by 57 one for each call until ``EINVAL`` is returned. The 58 ``v4l2_frmsizeenum.type`` field is set to 59 ``V4L2_FRMSIZE_TYPE_DISCRETE`` by the driver. Of the union only the 60 ``discrete`` member is valid. 61 62- **Step-wise:** The function returns success if the given index value 63 is zero and ``EINVAL`` for any other index value. The 64 ``v4l2_frmsizeenum.type`` field is set to 65 ``V4L2_FRMSIZE_TYPE_STEPWISE`` by the driver. Of the union only the 66 ``stepwise`` member is valid. 67 68- **Continuous:** This is a special case of the step-wise type above. 69 The function returns success if the given index value is zero and 70 ``EINVAL`` for any other index value. The ``v4l2_frmsizeenum.type`` 71 field is set to ``V4L2_FRMSIZE_TYPE_CONTINUOUS`` by the driver. Of 72 the union only the ``stepwise`` member is valid and the 73 ``step_width`` and ``step_height`` values are set to 1. 74 75When the application calls the function with index zero, it must check 76the ``type`` field to determine the type of frame size enumeration the 77device supports. Only for the ``V4L2_FRMSIZE_TYPE_DISCRETE`` type does 78it make sense to increase the index value to receive more frame sizes. 79 80.. note:: 81 82 The order in which the frame sizes are returned has no special 83 meaning. In particular does it not say anything about potential default 84 format sizes. 85 86Applications can assume that the enumeration data does not change 87without any interaction from the application itself. This means that the 88enumeration data is consistent if the application does not perform any 89other ioctl calls while it runs the frame size enumeration. 90 91 92Structs 93======= 94 95In the structs below, *IN* denotes a value that has to be filled in by 96the application, *OUT* denotes values that the driver fills in. The 97application should zero out all members except for the *IN* fields. 98 99 100.. c:type:: v4l2_frmsize_discrete 101 102.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 103 104.. flat-table:: struct v4l2_frmsize_discrete 105 :header-rows: 0 106 :stub-columns: 0 107 :widths: 1 1 2 108 109 * - __u32 110 - ``width`` 111 - Width of the frame [pixel]. 112 * - __u32 113 - ``height`` 114 - Height of the frame [pixel]. 115 116 117 118.. c:type:: v4l2_frmsize_stepwise 119 120.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 121 122.. flat-table:: struct v4l2_frmsize_stepwise 123 :header-rows: 0 124 :stub-columns: 0 125 :widths: 1 1 2 126 127 * - __u32 128 - ``min_width`` 129 - Minimum frame width [pixel]. 130 * - __u32 131 - ``max_width`` 132 - Maximum frame width [pixel]. 133 * - __u32 134 - ``step_width`` 135 - Frame width step size [pixel]. 136 * - __u32 137 - ``min_height`` 138 - Minimum frame height [pixel]. 139 * - __u32 140 - ``max_height`` 141 - Maximum frame height [pixel]. 142 * - __u32 143 - ``step_height`` 144 - Frame height step size [pixel]. 145 146 147 148.. c:type:: v4l2_frmsizeenum 149 150.. tabularcolumns:: |p{1.4cm}|p{5.9cm}|p{2.3cm}|p{8.0cm}| 151 152.. flat-table:: struct v4l2_frmsizeenum 153 :header-rows: 0 154 :stub-columns: 0 155 156 * - __u32 157 - ``index`` 158 - IN: Index of the given frame size in the enumeration. 159 * - __u32 160 - ``pixel_format`` 161 - IN: Pixel format for which the frame sizes are enumerated. 162 * - __u32 163 - ``type`` 164 - OUT: Frame size type the device supports. 165 * - union { 166 - (anonymous) 167 - OUT: Frame size with the given index. 168 * - struct :c:type:`v4l2_frmsize_discrete` 169 - ``discrete`` 170 - 171 * - struct :c:type:`v4l2_frmsize_stepwise` 172 - ``stepwise`` 173 - 174 * - } 175 - 176 - 177 * - __u32 178 - ``reserved[2]`` 179 - Reserved space for future use. Must be zeroed by drivers and 180 applications. 181 182 183 184Enums 185===== 186 187 188.. c:type:: v4l2_frmsizetypes 189 190.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| 191 192.. flat-table:: enum v4l2_frmsizetypes 193 :header-rows: 0 194 :stub-columns: 0 195 :widths: 3 1 4 196 197 * - ``V4L2_FRMSIZE_TYPE_DISCRETE`` 198 - 1 199 - Discrete frame size. 200 * - ``V4L2_FRMSIZE_TYPE_CONTINUOUS`` 201 - 2 202 - Continuous frame size. 203 * - ``V4L2_FRMSIZE_TYPE_STEPWISE`` 204 - 3 205 - Step-wise defined frame size. 206 207 208Return Value 209============ 210 211On success 0 is returned, on error -1 and the ``errno`` variable is set 212appropriately. The generic error codes are described at the 213:ref:`Generic Error Codes <gen-errors>` chapter. 214