ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS &manvol; VIDIOC_G_DV_TIMINGS VIDIOC_S_DV_TIMINGS Get or set DV timings for input or output int ioctl int fd int request struct v4l2_dv_timings *argp fd &fd; request VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS argp To set DV timings for the input or output, applications use the VIDIOC_S_DV_TIMINGS ioctl and to get the current timings, applications use the VIDIOC_G_DV_TIMINGS ioctl. The detailed timing information is filled in using the structure &v4l2-dv-timings;. These ioctls take a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported or the timing values are not correct, the driver returns &EINVAL;. The linux/v4l2-dv-timings.h header can be used to get the timings of the formats in the and standards. If the current input or output does not support DV timings (e.g. if &VIDIOC-ENUMINPUT; does not set the V4L2_IN_CAP_DV_TIMINGS flag), then &ENODATA; is returned. &return-value; EINVAL This ioctl is not supported, or the VIDIOC_S_DV_TIMINGS parameter was unsuitable. ENODATA Digital video timings are not supported for this input or output. EBUSY The device is busy and therefore can not change the timings. &cs-str; __u32 width Width of the active video in pixels. __u32 height Height of the active video frame in lines. So for interlaced formats the height of the active video in each field is height/2. __u32 interlaced Progressive (0) or interlaced (1) __u32 polarities This is a bit mask that defines polarities of sync signals. bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set (1) it is positive polarity and if is cleared (0), it is negative polarity. __u64 pixelclock Pixel clock in Hz. Ex. 74.25MHz->74250000 __u32 hfrontporch Horizontal front porch in pixels __u32 hsync Horizontal sync length in pixels __u32 hbackporch Horizontal back porch in pixels __u32 vfrontporch Vertical front porch in lines. For interlaced formats this refers to the odd field (aka field 1). __u32 vsync Vertical sync length in lines. For interlaced formats this refers to the odd field (aka field 1). __u32 vbackporch Vertical back porch in lines. For interlaced formats this refers to the odd field (aka field 1). __u32 il_vfrontporch Vertical front porch in lines for the even field (aka field 2) of interlaced field formats. Must be 0 for progressive formats. __u32 il_vsync Vertical sync length in lines for the even field (aka field 2) of interlaced field formats. Must be 0 for progressive formats. __u32 il_vbackporch Vertical back porch in lines for the even field (aka field 2) of interlaced field formats. Must be 0 for progressive formats. __u32 standards The video standard(s) this format belongs to. This will be filled in by the driver. Applications must set this to 0. See for a list of standards. __u32 flags Several flags giving more information about the format. See for a description of the flags. &cs-str; __u32 type Type of DV timings as listed in . union &v4l2-bt-timings; bt Timings defined by BT.656/1120 specifications __u32 reserved[32] &cs-str; Timing type value Description V4L2_DV_BT_656_1120 0 BT.656/1120 timings &cs-str; Timing standard Description V4L2_DV_BT_STD_CEA861 The timings follow the CEA-861 Digital TV Profile standard V4L2_DV_BT_STD_DMT The timings follow the VESA Discrete Monitor Timings standard V4L2_DV_BT_STD_CVT The timings follow the VESA Coordinated Video Timings standard V4L2_DV_BT_STD_GTF The timings follow the VESA Generalized Timings Formula standard &cs-str; Flag Description V4L2_DV_FL_REDUCED_BLANKING CVT/GTF specific: the timings use reduced blanking (CVT) or the 'Secondary GTF' curve (GTF). In both cases the horizontal and/or vertical blanking intervals are reduced, allowing a higher resolution over the same bandwidth. This is a read-only flag, applications must not set this. V4L2_DV_FL_CAN_REDUCE_FPS CEA-861 specific: set for CEA-861 formats with a framerate that is a multiple of six. These formats can be optionally played at 1 / 1.001 speed to be compatible with 60 Hz based standards such as NTSC and PAL-M that use a framerate of 29.97 frames per second. If the transmitter can't generate such frequencies, then the flag will also be cleared. This is a read-only flag, applications must not set this. V4L2_DV_FL_REDUCED_FPS CEA-861 specific: only valid for video transmitters, the flag is cleared by receivers. It is also only valid for formats with the V4L2_DV_FL_CAN_REDUCE_FPS flag set, for other formats the flag will be cleared by the driver. If the application sets this flag, then the pixelclock used to set up the transmitter is divided by 1.001 to make it compatible with NTSC framerates. If the transmitter can't generate such frequencies, then the flag will also be cleared. V4L2_DV_FL_HALF_LINE Specific to interlaced formats: if set, then the vertical frontporch of field 1 (aka the odd field) is really one half-line longer and the vertical backporch of field 2 (aka the even field) is really one half-line shorter, so each field has exactly the same number of half-lines. Whether half-lines can be detected or used depends on the hardware. V4L2_DV_FL_IS_CE_VIDEO If set, then this is a Consumer Electronics (CE) video format. Such formats differ from other formats (commonly called IT formats) in that if R'G'B' encoding is used then by default the R'G'B' values use limited range (i.e. 16-235) as opposed to full range (i.e. 0-255). All formats defined in CEA-861 except for the 640x480p59.94 format are CE formats.