^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) .. c:namespace:: V4L
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) .. _VIDIOC_CROPCAP:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) ********************
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) ioctl VIDIOC_CROPCAP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) ********************
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) ====
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) VIDIOC_CROPCAP - Information about the video cropping and scaling abilities
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) Synopsis
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) ========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) .. c:macro:: VIDIOC_CROPCAP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) ``int ioctl(int fd, VIDIOC_CROPCAP, struct v4l2_cropcap *argp)``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) Arguments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) =========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) ``fd``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) File descriptor returned by :c:func:`open()`.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) ``argp``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) Pointer to struct :c:type:`v4l2_cropcap`.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) ===========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) Applications use this function to query the cropping limits, the pixel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) aspect of images and to calculate scale factors. They set the ``type``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) field of a v4l2_cropcap structure to the respective buffer (stream)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) type and call the :ref:`VIDIOC_CROPCAP` ioctl with a pointer to this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) structure. Drivers fill the rest of the structure. The results are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) constant except when switching the video standard. Remember this switch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) can occur implicit when switching the video input or output.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) This ioctl must be implemented for video capture or output devices that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) support cropping and/or scaling and/or have non-square pixels, and for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) overlay devices.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) .. c:type:: v4l2_cropcap
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) .. flat-table:: struct v4l2_cropcap
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) :header-rows: 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) :stub-columns: 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) :widths: 1 1 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * - __u32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) - ``type``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) - Type of the data stream, set by the application. Only these types
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``, ``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) ``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE`` and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) ``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :c:type:`v4l2_buf_type` and the note below.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * - struct :ref:`v4l2_rect <v4l2-rect-crop>`
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) - ``bounds``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) - Defines the window within capturing or output is possible, this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) may exclude for example the horizontal and vertical blanking
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) areas. The cropping rectangle cannot exceed these limits. Width
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) and height are defined in pixels, the driver writer is free to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) choose origin and units of the coordinate system in the analog
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) domain.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * - struct :ref:`v4l2_rect <v4l2-rect-crop>`
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) - ``defrect``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) - Default cropping rectangle, it shall cover the "whole picture".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) Assuming pixel aspect 1/1 this could be for example a 640 × 480
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) rectangle for NTSC, a 768 × 576 rectangle for PAL and SECAM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) centered over the active picture area. The same co-ordinate system
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) as for ``bounds`` is used.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) * - struct :c:type:`v4l2_fract`
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) - ``pixelaspect``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) - This is the pixel aspect (y / x) when no scaling is applied, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) ratio of the actual sampling frequency and the frequency required
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) to get square pixels.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) When cropping coordinates refer to square pixels, the driver sets
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) ``pixelaspect`` to 1/1. Other common values are 54/59 for PAL and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) SECAM, 11/10 for NTSC sampled according to [:ref:`itu601`].
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) .. note::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) Unfortunately in the case of multiplanar buffer types
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) (``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) this API was messed up with regards to how the :c:type:`v4l2_cropcap` ``type`` field
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) should be filled in. Some drivers only accepted the ``_MPLANE`` buffer type while
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) other drivers only accepted a non-multiplanar buffer type (i.e. without the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) ``_MPLANE`` at the end).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) Starting with kernel 4.13 both variations are allowed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) .. _v4l2-rect-crop:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) .. flat-table:: struct v4l2_rect
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) :header-rows: 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) :stub-columns: 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) :widths: 1 1 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) * - __s32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) - ``left``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) - Horizontal offset of the top, left corner of the rectangle, in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) pixels.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) * - __s32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) - ``top``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) - Vertical offset of the top, left corner of the rectangle, in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) pixels.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) * - __u32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) - ``width``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) - Width of the rectangle, in pixels.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) * - __u32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) - ``height``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) - Height of the rectangle, in pixels.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) Return Value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) ============
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) On success 0 is returned, on error -1 and the ``errno`` variable is set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) appropriately. The generic error codes are described at the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) :ref:`Generic Error Codes <gen-errors>` chapter.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) EINVAL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) The struct :c:type:`v4l2_cropcap` ``type`` is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) invalid.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) ENODATA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) Cropping is not supported for this input or output.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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