1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _common: 5 6################### 7Common API Elements 8################### 9Programming a V4L2 device consists of these steps: 10 11- Opening the device 12 13- Changing device properties, selecting a video and audio input, video 14 standard, picture brightness a. o. 15 16- Negotiating a data format 17 18- Negotiating an input/output method 19 20- The actual input/output loop 21 22- Closing the device 23 24In practice most steps are optional and can be executed out of order. It 25depends on the V4L2 device type, you can read about the details in 26:ref:`devices`. In this chapter we will discuss the basic concepts 27applicable to all devices. 28 29 30.. toctree:: 31 :maxdepth: 1 32 33 open 34 querycap 35 app-pri 36 video 37 audio 38 tuner 39 standard 40 dv-timings 41 control 42 extended-controls 43 ext-ctrls-camera 44 ext-ctrls-flash 45 ext-ctrls-image-source 46 ext-ctrls-image-process 47 ext-ctrls-codec 48 ext-ctrls-codec-stateless 49 ext-ctrls-jpeg 50 ext-ctrls-dv 51 ext-ctrls-rf-tuner 52 ext-ctrls-fm-tx 53 ext-ctrls-fm-rx 54 ext-ctrls-detect 55 ext-ctrls-colorimetry 56 fourcc 57 format 58 planar-apis 59 selection-api 60 crop 61 streaming-par 62