media/v4l/vidioc-subdev-g-frame-interval.rst

1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 VIDIOC_SUBDEV_G_FRAME_INTERVAL - VIDIOC_SUBDEV_S_FRAME_INTERVAL - Get or set the frame interval on …
38 These ioctls are used to get and set the frame interval at specific
39 subdev pads in the image pipeline. The frame interval only makes sense
40 for sub-devices that can control the frame period on their own. This
41 includes, for instance, image sensors and TV tuners. Sub-devices that
42 don't support frame intervals must not implement these ioctls.
44 To retrieve the current frame interval applications set the ``pad``
51 To change the current frame interval applications set both the ``pad``
58 contains the current frame interval as would be returned by a
61 If the subdev device node has been registered in read-only mode, calls to
64 variable is set to ``-EPERM``.
71 Changing the frame interval shall never change the format. Changing the
72 format, on the other hand, may change the frame interval.
74 Sub-devices that support the frame interval ioctls should implement them
76 the same sub-device is not defined.
82 .. flat-table:: struct v4l2_subdev_frame_interval
83     :header-rows:  0
84     :stub-columns: 0
87     * - __u32
88       - ``pad``
89       - Pad number as reported by the media controller API.
90     * - struct :c:type:`v4l2_fract`
91       - ``interval``
92       - Period, in seconds, between consecutive video frames.
93     * - __u32
94       - ``stream``
95       - Stream identifier.
96     * - __u32
97       - ``which``
98       - Active or try frame interval, from enum
99 	:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
100     * - __u32
101       - ``reserved``\ [7]
102       - Reserved for future extensions. Applications and drivers must set
108 On success 0 is returned, on error -1 and the ``errno`` variable is set
110 :ref:`Generic Error Codes <gen-errors>` chapter.
113     The frame interval can't be changed because the pad is currently
121     non-existing pad, the ``which`` field has an unsupported value, or the pad
122     doesn't support frame intervals.
125     The ``VIDIOC_SUBDEV_S_FRAME_INTERVAL`` ioctl has been called on a read-only