mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
1.1 KiB
52 lines
1.1 KiB
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
|
.. c:namespace:: V4L |
|
|
|
.. _VIDIOC_OVERLAY: |
|
|
|
******************** |
|
ioctl VIDIOC_OVERLAY |
|
******************** |
|
|
|
Name |
|
==== |
|
|
|
VIDIOC_OVERLAY - Start or stop video overlay |
|
|
|
Synopsis |
|
======== |
|
|
|
.. c:macro:: VIDIOC_OVERLAY |
|
|
|
``int ioctl(int fd, VIDIOC_OVERLAY, const int *argp)`` |
|
|
|
Arguments |
|
========= |
|
|
|
``fd`` |
|
File descriptor returned by :c:func:`open()`. |
|
|
|
``argp`` |
|
Pointer to an integer. |
|
|
|
Description |
|
=========== |
|
|
|
This ioctl is part of the :ref:`video overlay <overlay>` I/O method. |
|
Applications call :ref:`VIDIOC_OVERLAY` to start or stop the overlay. It |
|
takes a pointer to an integer which must be set to zero by the |
|
application to stop overlay, to one to start. |
|
|
|
Drivers do not support :ref:`VIDIOC_STREAMON` or |
|
:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with |
|
``V4L2_BUF_TYPE_VIDEO_OVERLAY``. |
|
|
|
Return Value |
|
============ |
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set |
|
appropriately. The generic error codes are described at the |
|
:ref:`Generic Error Codes <gen-errors>` chapter. |
|
|
|
EINVAL |
|
The overlay parameters have not been set up. See :ref:`overlay` |
|
for the necessary steps.
|
|
|