1.. -*- coding: utf-8; mode: rst -*- 2 3.. _VIDIOC_G_DV_TIMINGS: 4 5********************************************** 6ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS 7********************************************** 8 9Name 10==== 11 12VIDIOC_G_DV_TIMINGS - VIDIOC_S_DV_TIMINGS - VIDIOC_SUBDEV_G_DV_TIMINGS - VIDIOC_SUBDEV_S_DV_TIMINGS - Get or set DV timings for input or output 13 14 15Synopsis 16======== 17 18.. c:function:: int ioctl( int fd, VIDIOC_G_DV_TIMINGS, struct v4l2_dv_timings *argp ) 19 :name: VIDIOC_G_DV_TIMINGS 20 21.. c:function:: int ioctl( int fd, VIDIOC_S_DV_TIMINGS, struct v4l2_dv_timings *argp ) 22 :name: VIDIOC_S_DV_TIMINGS 23 24.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_DV_TIMINGS, struct v4l2_dv_timings *argp ) 25 :name: VIDIOC_SUBDEV_G_DV_TIMINGS 26 27.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_DV_TIMINGS, struct v4l2_dv_timings *argp ) 28 :name: VIDIOC_SUBDEV_S_DV_TIMINGS 29 30 31Arguments 32========= 33 34``fd`` 35 File descriptor returned by :ref:`open() <func-open>`. 36 37``argp`` 38 Pointer to struct :c:type:`v4l2_dv_timings`. 39 40 41Description 42=========== 43 44To set DV timings for the input or output, applications use the 45:ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl and to get the current timings, 46applications use the :ref:`VIDIOC_G_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl. The detailed timing 47information is filled in using the structure struct 48:c:type:`v4l2_dv_timings`. These ioctls take a 49pointer to the struct :c:type:`v4l2_dv_timings` 50structure as argument. If the ioctl is not supported or the timing 51values are not correct, the driver returns ``EINVAL`` error code. 52 53The ``linux/v4l2-dv-timings.h`` header can be used to get the timings of 54the formats in the :ref:`cea861` and :ref:`vesadmt` standards. If 55the current input or output does not support DV timings (e.g. if 56:ref:`VIDIOC_ENUMINPUT` does not set the 57``V4L2_IN_CAP_DV_TIMINGS`` flag), then ``ENODATA`` error code is returned. 58 59 60Return Value 61============ 62 63On success 0 is returned, on error -1 and the ``errno`` variable is set 64appropriately. The generic error codes are described at the 65:ref:`Generic Error Codes <gen-errors>` chapter. 66 67EINVAL 68 This ioctl is not supported, or the :ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` 69 parameter was unsuitable. 70 71ENODATA 72 Digital video timings are not supported for this input or output. 73 74EBUSY 75 The device is busy and therefore can not change the timings. 76 77 78.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 79 80.. c:type:: v4l2_bt_timings 81 82.. flat-table:: struct v4l2_bt_timings 83 :header-rows: 0 84 :stub-columns: 0 85 :widths: 1 1 2 86 87 * - __u32 88 - ``width`` 89 - Width of the active video in pixels. 90 * - __u32 91 - ``height`` 92 - Height of the active video frame in lines. So for interlaced 93 formats the height of the active video in each field is 94 ``height``/2. 95 * - __u32 96 - ``interlaced`` 97 - Progressive (``V4L2_DV_PROGRESSIVE``) or interlaced (``V4L2_DV_INTERLACED``). 98 * - __u32 99 - ``polarities`` 100 - This is a bit mask that defines polarities of sync signals. bit 0 101 (``V4L2_DV_VSYNC_POS_POL``) is for vertical sync polarity and bit 102 1 (``V4L2_DV_HSYNC_POS_POL``) is for horizontal sync polarity. If 103 the bit is set (1) it is positive polarity and if is cleared (0), 104 it is negative polarity. 105 * - __u64 106 - ``pixelclock`` 107 - Pixel clock in Hz. Ex. 74.25MHz->74250000 108 * - __u32 109 - ``hfrontporch`` 110 - Horizontal front porch in pixels 111 * - __u32 112 - ``hsync`` 113 - Horizontal sync length in pixels 114 * - __u32 115 - ``hbackporch`` 116 - Horizontal back porch in pixels 117 * - __u32 118 - ``vfrontporch`` 119 - Vertical front porch in lines. For interlaced formats this refers 120 to the odd field (aka field 1). 121 * - __u32 122 - ``vsync`` 123 - Vertical sync length in lines. For interlaced formats this refers 124 to the odd field (aka field 1). 125 * - __u32 126 - ``vbackporch`` 127 - Vertical back porch in lines. For interlaced formats this refers 128 to the odd field (aka field 1). 129 * - __u32 130 - ``il_vfrontporch`` 131 - Vertical front porch in lines for the even field (aka field 2) of 132 interlaced field formats. Must be 0 for progressive formats. 133 * - __u32 134 - ``il_vsync`` 135 - Vertical sync length in lines for the even field (aka field 2) of 136 interlaced field formats. Must be 0 for progressive formats. 137 * - __u32 138 - ``il_vbackporch`` 139 - Vertical back porch in lines for the even field (aka field 2) of 140 interlaced field formats. Must be 0 for progressive formats. 141 * - __u32 142 - ``standards`` 143 - The video standard(s) this format belongs to. This will be filled 144 in by the driver. Applications must set this to 0. See 145 :ref:`dv-bt-standards` for a list of standards. 146 * - __u32 147 - ``flags`` 148 - Several flags giving more information about the format. See 149 :ref:`dv-bt-flags` for a description of the flags. 150 * - struct :c:type:`v4l2_fract` 151 - ``picture_aspect`` 152 - The picture aspect if the pixels are not square. Only valid if the 153 ``V4L2_DV_FL_HAS_PICTURE_ASPECT`` flag is set. 154 * - __u8 155 - ``cea861_vic`` 156 - The Video Identification Code according to the CEA-861 standard. 157 Only valid if the ``V4L2_DV_FL_HAS_CEA861_VIC`` flag is set. 158 * - __u8 159 - ``hdmi_vic`` 160 - The Video Identification Code according to the HDMI standard. 161 Only valid if the ``V4L2_DV_FL_HAS_HDMI_VIC`` flag is set. 162 * - __u8 163 - ``reserved[46]`` 164 - Reserved for future extensions. Drivers and applications must set 165 the array to zero. 166 167 168.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{7.0cm}|p{3.5cm}| 169 170.. c:type:: v4l2_dv_timings 171 172.. flat-table:: struct v4l2_dv_timings 173 :header-rows: 0 174 :stub-columns: 0 175 :widths: 1 1 2 1 176 177 * - __u32 178 - ``type`` 179 - 180 - Type of DV timings as listed in :ref:`dv-timing-types`. 181 * - union 182 - 183 - 184 * - 185 - struct :c:type:`v4l2_bt_timings` 186 - ``bt`` 187 - Timings defined by BT.656/1120 specifications 188 * - 189 - __u32 190 - ``reserved``\ [32] 191 - 192 193.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 194 195.. _dv-timing-types: 196 197.. flat-table:: DV Timing types 198 :header-rows: 0 199 :stub-columns: 0 200 :widths: 1 1 2 201 202 * - Timing type 203 - value 204 - Description 205 * - 206 - 207 - 208 * - ``V4L2_DV_BT_656_1120`` 209 - 0 210 - BT.656/1120 timings 211 212.. tabularcolumns:: |p{4.5cm}|p{12.8cm}| 213 214.. _dv-bt-standards: 215 216.. flat-table:: DV BT Timing standards 217 :header-rows: 0 218 :stub-columns: 0 219 220 * - Timing standard 221 - Description 222 * - ``V4L2_DV_BT_STD_CEA861`` 223 - The timings follow the CEA-861 Digital TV Profile standard 224 * - ``V4L2_DV_BT_STD_DMT`` 225 - The timings follow the VESA Discrete Monitor Timings standard 226 * - ``V4L2_DV_BT_STD_CVT`` 227 - The timings follow the VESA Coordinated Video Timings standard 228 * - ``V4L2_DV_BT_STD_GTF`` 229 - The timings follow the VESA Generalized Timings Formula standard 230 * - ``V4L2_DV_BT_STD_SDI`` 231 - The timings follow the SDI Timings standard. 232 There are no horizontal syncs/porches at all in this format. 233 Total blanking timings must be set in hsync or vsync fields only. 234 235.. tabularcolumns:: |p{7.0cm}|p{10.5cm}| 236 237.. _dv-bt-flags: 238 239.. flat-table:: DV BT Timing flags 240 :header-rows: 0 241 :stub-columns: 0 242 243 * - Flag 244 - Description 245 * - ``V4L2_DV_FL_REDUCED_BLANKING`` 246 - CVT/GTF specific: the timings use reduced blanking (CVT) or the 247 'Secondary GTF' curve (GTF). In both cases the horizontal and/or 248 vertical blanking intervals are reduced, allowing a higher 249 resolution over the same bandwidth. This is a read-only flag, 250 applications must not set this. 251 * - ``V4L2_DV_FL_CAN_REDUCE_FPS`` 252 - CEA-861 specific: set for CEA-861 formats with a framerate that is 253 a multiple of six. These formats can be optionally played at 1 / 254 1.001 speed to be compatible with 60 Hz based standards such as 255 NTSC and PAL-M that use a framerate of 29.97 frames per second. If 256 the transmitter can't generate such frequencies, then the flag 257 will also be cleared. This is a read-only flag, applications must 258 not set this. 259 * - ``V4L2_DV_FL_REDUCED_FPS`` 260 - CEA-861 specific: only valid for video transmitters, the flag is 261 cleared by receivers. It is also only valid for formats with the 262 ``V4L2_DV_FL_CAN_REDUCE_FPS`` flag set, for other formats the 263 flag will be cleared by the driver. If the application sets this 264 flag, then the pixelclock used to set up the transmitter is 265 divided by 1.001 to make it compatible with NTSC framerates. If 266 the transmitter can't generate such frequencies, then the flag 267 will also be cleared. 268 * - ``V4L2_DV_FL_HALF_LINE`` 269 - Specific to interlaced formats: if set, then the vertical 270 frontporch of field 1 (aka the odd field) is really one half-line 271 longer and the vertical backporch of field 2 (aka the even field) 272 is really one half-line shorter, so each field has exactly the 273 same number of half-lines. Whether half-lines can be detected or 274 used depends on the hardware. 275 * - ``V4L2_DV_FL_IS_CE_VIDEO`` 276 - If set, then this is a Consumer Electronics (CE) video format. 277 Such formats differ from other formats (commonly called IT 278 formats) in that if R'G'B' encoding is used then by default the 279 R'G'B' values use limited range (i.e. 16-235) as opposed to full 280 range (i.e. 0-255). All formats defined in CEA-861 except for the 281 640x480p59.94 format are CE formats. 282 * - ``V4L2_DV_FL_FIRST_FIELD_EXTRA_LINE`` 283 - Some formats like SMPTE-125M have an interlaced signal with a odd 284 total height. For these formats, if this flag is set, the first 285 field has the extra line. Else, it is the second field. 286 * - ``V4L2_DV_FL_HAS_PICTURE_ASPECT`` 287 - If set, then the picture_aspect field is valid. Otherwise assume that 288 the pixels are square, so the picture aspect ratio is the same as the 289 width to height ratio. 290 * - ``V4L2_DV_FL_HAS_CEA861_VIC`` 291 - If set, then the cea861_vic field is valid and contains the Video 292 Identification Code as per the CEA-861 standard. 293 * - ``V4L2_DV_FL_HAS_HDMI_VIC`` 294 - If set, then the hdmi_vic field is valid and contains the Video 295 Identification Code as per the HDMI standard (HDMI Vendor Specific 296 InfoFrame). 297