tjh.dev
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 Device Driver
29 Part of the Linux Kernel that implements support for a hardware
30 component.
31
32 Device Node
33 A character device node in the file system used to control and
34 transfer data in and out of a Kernel driver.
35
36 Digital TV API
37 **Previously known as DVB API**
38
39 An API designed to control a subset of the :term:`Media Hardware`
40 that implements digital TV (e. g. DVB, ATSC, ISDB, etc).
41
42 See :ref:`dvbapi`.
43
44 DSP
45 **Digital Signal Processor**
46
47 A specialized :term:`Microprocessor`, with its architecture
48 optimized for the operational needs of digital signal processing.
49
50 FPGA
51 **Field-programmable Gate Array**
52
53 An :term:`IC` circuit designed to be configured by a customer or
54 a designer after manufacturing.
55
56 See https://en.wikipedia.org/wiki/Field-programmable_gate_array.
57
58 Hardware Component
59 A subset of the :term:`Media Hardware`. For example an :term:`I²C` or
60 :term:`SPI` device, or an :term:`IP Block` inside an
61 :term:`SoC` or :term:`FPGA`.
62
63 Hardware Peripheral
64 A group of :term:`hardware components <Hardware Component>` that
65 together make a larger user-facing functional peripheral. For
66 instance, the :term:`SoC` :term:`ISP` :term:`IP Block`
67 and the external camera sensors together make a camera hardware
68 peripheral.
69
70 Also known as :term:`Peripheral`.
71
72 I²C
73 **Inter-Integrated Circuit**
74
75 A multi-master, multi-slave, packet switched, single-ended,
76 serial computer bus used to control some hardware components
77 like sub-device hardware components.
78
79 See http://www.nxp.com/docs/en/user-guide/UM10204.pdf.
80
81 IC
82 **Integrated circuit**
83
84 A set of electronic circuits on one small flat piece of
85 semiconductor material, normally silicon.
86
87 Also known as chip.
88
89 IP Block
90 **Intellectual property core**
91
92 In electronic design a semiconductor intellectual property core,
93 is a reusable unit of logic, cell, or integrated circuit layout
94 design that is the intellectual property of one party.
95 IP Blocks may be licensed to another party or can be owned
96 and used by a single party alone.
97
98 See https://en.wikipedia.org/wiki/Semiconductor_intellectual_property_core).
99
100 ISP
101 **Image Signal Processor**
102
103 A specialized processor that implements a set of algorithms for
104 processing image data. ISPs may implement algorithms for lens
105 shading correction, demosaicing, scaling and pixel format conversion
106 as well as produce statistics for the use of the control
107 algorithms (e.g. automatic exposure, white balance and focus).
108
109 Media API
110 A set of userspace APIs used to control the media hardware. It is
111 composed by:
112
113 - :term:`CEC API`;
114 - :term:`Digital TV API`;
115 - :term:`MC API`;
116 - :term:`RC API`; and
117 - :term:`V4L2 API`.
118
119 See Documentation/userspace-api/media/index.rst.
120
121 MC API
122 **Media Controller API**
123
124 An API designed to expose and control the relationships between
125 multimedia devices and sub-devices.
126
127 See :ref:`media_controller`.
128
129 MC-centric
130 :term:`V4L2 Hardware` device driver that requires :term:`MC API`.
131
132 Such drivers have ``V4L2_CAP_IO_MC`` device_caps field set
133 (see :ref:`VIDIOC_QUERYCAP`).
134
135 See :ref:`v4l2_hardware_control` for more details.
136
137 Media Hardware
138 Subset of the hardware that is supported by the Linux Media API.
139
140 This includes audio and video capture and playback hardware,
141 digital and analog TV, camera sensors, ISPs, remote controllers,
142 codecs, HDMI Consumer Electronics Control, HDMI capture, etc.
143
144 Microprocessor
145 Electronic circuitry that carries out the instructions of a
146 computer program by performing the basic arithmetic, logical,
147 control and input/output (I/O) operations specified by the
148 instructions on a single integrated circuit.
149
150 Peripheral
151 The same as :term:`Hardware Peripheral`.
152
153 RC API
154 **Remote Controller API**
155
156 An API designed to receive and transmit data from remote
157 controllers.
158
159 See :ref:`remote_controllers`.
160
161 SMBus
162 A subset of I²C, which defines a stricter usage of the bus.
163
164 SPI
165 **Serial Peripheral Interface Bus**
166
167 Synchronous serial communication interface specification used for
168 short distance communication, primarily in embedded systems.
169
170 SoC
171 **System on a Chip**
172
173 An integrated circuit that integrates all components of a computer
174 or other electronic systems.
175
176 V4L2 API
177 **V4L2 userspace API**
178
179 The userspace API defined in :ref:`v4l2spec`, which is used to
180 control a V4L2 hardware.
181
182 V4L2 Device Node
183 A :term:`Device Node` that is associated to a V4L driver.
184
185 The V4L2 device node naming is specified at :ref:`v4l2_device_naming`.
186
187 V4L2 Hardware
188 Part of the media hardware which is supported by the :term:`V4L2 API`.
189
190 V4L2 Sub-device
191 V4L2 hardware components that aren't controlled by a
192 :term:`Bridge Driver`. See :ref:`subdev`.
193
194 Video-node-centric
195 V4L2 device driver that doesn't require a media controller to be used.
196
197 Such drivers have the ``V4L2_CAP_IO_MC`` device_caps field unset
198 (see :ref:`VIDIOC_QUERYCAP`).
199
200 V4L2 Sub-device API
201 Part of the :term:`V4L2 API` which control
202 :term:`V4L2 sub-devices <V4L2 Sub-device>`, like sensors,
203 HDMI receivers, scalers, deinterlacers.
204
205 See :ref:`v4l2_hardware_control` for more details.