summaryrefslogtreecommitdiff
path: root/Documentation/media/uapi/v4l/vidioc-overlay.rst
blob: 1383e3db25fcee4c3ef8ffe933ffd3c1668790b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
.. -*- coding: utf-8; mode: rst -*-

.. _VIDIOC_OVERLAY:

********************
ioctl VIDIOC_OVERLAY
********************

Name
====

VIDIOC_OVERLAY - Start or stop video overlay


Synopsis
========

.. c:function:: int ioctl( int fd, VIDIOC_OVERLAY, const int *argp )
    :name: VIDIOC_OVERLAY


Arguments
=========

``fd``
    File descriptor returned by :ref:`open() <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.