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Linux kernel mirror (for testing)
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1.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
2
3========
4Glossary
5========
6
7.. note::
8
9 The goal of this section is to standardize the terms used within the media
10 userspace API documentation. This is Work In Progress.
11
12.. Please keep the glossary entries in alphabetical order
13
14.. glossary::
15
16 Bridge Driver
17 A :term:`Device Driver` that implements the main logic to talk with
18 media hardware.
19
20 CEC API
21 **Consumer Electronics Control API**
22
23 An API designed to receive and transmit data via an HDMI
24 CEC interface.
25
26 See :ref:`cec`.
27
28 Data Unit
29
30 Unit of data transported by a bus. On parallel buses, the data unit
31 consists of one or more related samples while on serial buses the data
32 unit is logical. If the data unit is image data, it may also be called a
33 pixel.
34
35 Device Driver
36 Part of the Linux Kernel that implements support for a hardware
37 component.
38
39 Device Node
40 A character device node in the file system used to control and
41 transfer data in and out of a Kernel driver.
42
43 Digital TV API
44 **Previously known as DVB API**
45
46 An API designed to control a subset of the :term:`Media Hardware`
47 that implements digital TV (e. g. DVB, ATSC, ISDB, etc).
48
49 See :ref:`dvbapi`.
50
51 DSP
52 **Digital Signal Processor**
53
54 A specialized :term:`Microprocessor`, with its architecture
55 optimized for the operational needs of digital signal processing.
56
57 FPGA
58 **Field-programmable Gate Array**
59
60 An :term:`IC` circuit designed to be configured by a customer or
61 a designer after manufacturing.
62
63 See https://en.wikipedia.org/wiki/Field-programmable_gate_array.
64
65 Hardware Component
66 A subset of the :term:`Media Hardware`. For example an :term:`I²C` or
67 :term:`SPI` device, or an :term:`IP Block` inside an
68 :term:`SoC` or :term:`FPGA`.
69
70 Hardware Peripheral
71 A group of :term:`hardware components <Hardware Component>` that
72 together make a larger user-facing functional peripheral. For
73 instance, the :term:`SoC` :term:`ISP` :term:`IP Block`
74 and the external camera sensors together make a camera hardware
75 peripheral.
76
77 Also known as :term:`Peripheral`.
78
79 I²C
80 **Inter-Integrated Circuit**
81
82 A multi-master, multi-slave, packet switched, single-ended,
83 serial computer bus used to control some hardware components
84 like sub-device hardware components.
85
86 See http://www.nxp.com/docs/en/user-guide/UM10204.pdf.
87
88 IC
89 **Integrated circuit**
90
91 A set of electronic circuits on one small flat piece of
92 semiconductor material, normally silicon.
93
94 Also known as chip.
95
96 IP Block
97 **Intellectual property core**
98
99 In electronic design a semiconductor intellectual property core,
100 is a reusable unit of logic, cell, or integrated circuit layout
101 design that is the intellectual property of one party.
102 IP Blocks may be licensed to another party or can be owned
103 and used by a single party alone.
104
105 See https://en.wikipedia.org/wiki/Semiconductor_intellectual_property_core).
106
107 ISP
108 **Image Signal Processor**
109
110 A specialized processor that implements a set of algorithms for
111 processing image data. ISPs may implement algorithms for lens
112 shading correction, demosaicing, scaling and pixel format conversion
113 as well as produce statistics for the use of the control
114 algorithms (e.g. automatic exposure, white balance and focus).
115
116 Media API
117 A set of userspace APIs used to control the media hardware. It is
118 composed by:
119
120 - :term:`CEC API`;
121 - :term:`Digital TV API`;
122 - :term:`MC API`;
123 - :term:`RC API`; and
124 - :term:`V4L2 API`.
125
126 See Documentation/userspace-api/media/index.rst.
127
128 MC API
129 **Media Controller API**
130
131 An API designed to expose and control the relationships between
132 multimedia devices and sub-devices.
133
134 See :ref:`media_controller`.
135
136 MC-centric
137 :term:`V4L2 Hardware` device driver that requires :term:`MC API`.
138
139 Such drivers have ``V4L2_CAP_IO_MC`` device_caps field set
140 (see :ref:`VIDIOC_QUERYCAP`).
141
142 See :ref:`v4l2_hardware_control` for more details.
143
144 Media Hardware
145 Subset of the hardware that is supported by the Linux Media API.
146
147 This includes audio and video capture and playback hardware,
148 digital and analog TV, camera sensors, ISPs, remote controllers,
149 codecs, HDMI Consumer Electronics Control, HDMI capture, etc.
150
151 Microprocessor
152 Electronic circuitry that carries out the instructions of a
153 computer program by performing the basic arithmetic, logical,
154 control and input/output (I/O) operations specified by the
155 instructions on a single integrated circuit.
156
157 Peripheral
158 The same as :term:`Hardware Peripheral`.
159
160 RC API
161 **Remote Controller API**
162
163 An API designed to receive and transmit data from remote
164 controllers.
165
166 See :ref:`remote_controllers`.
167
168 SMBus
169 A subset of I²C, which defines a stricter usage of the bus.
170
171 SPI
172 **Serial Peripheral Interface Bus**
173
174 Synchronous serial communication interface specification used for
175 short distance communication, primarily in embedded systems.
176
177 SoC
178 **System on a Chip**
179
180 An integrated circuit that integrates all components of a computer
181 or other electronic systems.
182
183 Stream
184 A distinct flow of data (image data or metadata) from an initial source
185 to a final sink. The initial source may be e.g. an image sensor and the
186 final sink e.g. a memory buffer.
187
188 V4L2 API
189 **V4L2 userspace API**
190
191 The userspace API defined in :ref:`v4l2spec`, which is used to
192 control a V4L2 hardware.
193
194 V4L2 Device Node
195 A :term:`Device Node` that is associated to a V4L driver.
196
197 The V4L2 device node naming is specified at :ref:`v4l2_device_naming`.
198
199 V4L2 Hardware
200 Part of the media hardware which is supported by the :term:`V4L2 API`.
201
202 V4L2 Sub-device
203 V4L2 hardware components that aren't controlled by a
204 :term:`Bridge Driver`. See :ref:`subdev`.
205
206 Video-node-centric
207 V4L2 device driver that doesn't require a media controller to be used.
208
209 Such drivers have the ``V4L2_CAP_IO_MC`` device_caps field unset
210 (see :ref:`VIDIOC_QUERYCAP`).
211
212 V4L2 Sub-device API
213 Part of the :term:`V4L2 API` which control
214 :term:`V4L2 sub-devices <V4L2 Sub-device>`, like sensors,
215 HDMI receivers, scalers, deinterlacers.
216
217 See :ref:`v4l2_hardware_control` for more details.