.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later

.. _common:

###################
Common API Elements
###################
Programming a V4L2 device consists of these steps:

-  Opening the device

-  Changing device properties, selecting a video and audio input, video
   standard, picture brightness a. o.

-  Negotiating a data format

-  Negotiating an input/output method

-  The actual input/output loop

-  Closing the device

In practice most steps are optional and can be executed out of order. It
depends on the V4L2 device type, you can read about the details in
:ref:`devices`. In this chapter we will discuss the basic concepts
applicable to all devices.


.. toctree::
    :maxdepth: 1

    open
    querycap
    app-pri
    video
    audio
    tuner
    standard
    dv-timings
    control
    extended-controls
    ext-ctrls-camera
    ext-ctrls-flash
    ext-ctrls-image-source
    ext-ctrls-image-process
    ext-ctrls-codec
    ext-ctrls-codec-stateless
    ext-ctrls-jpeg
    ext-ctrls-dv
    ext-ctrls-rf-tuner
    ext-ctrls-fm-tx
    ext-ctrls-fm-rx
    ext-ctrls-detect
    fourcc
    format
    planar-apis
    selection-api
    crop
    streaming-par
