libcamera v0.4.0
Supporting cameras in Linux since 2019
 
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v4l2_videodevice.h
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2/*
3 * Copyright (C) 2019, Google Inc.
4 *
5 * V4L2 Video Device
6 */
7
8#pragma once
9
10#include <array>
11#include <atomic>
12#include <memory>
13#include <optional>
14#include <ostream>
15#include <stdint.h>
16#include <string>
17#include <unordered_set>
18#include <vector>
19
20#include <linux/videodev2.h>
21
23#include <libcamera/base/log.h>
28
31#include <libcamera/geometry.h>
33
37
38namespace libcamera {
39
40class EventNotifier;
41class MediaDevice;
42class MediaEntity;
43
44struct V4L2Capability final : v4l2_capability {
45 const char *driver() const
46 {
47 return reinterpret_cast<const char *>(v4l2_capability::driver);
48 }
49 const char *card() const
50 {
51 return reinterpret_cast<const char *>(v4l2_capability::card);
52 }
53 const char *bus_info() const
54 {
55 return reinterpret_cast<const char *>(v4l2_capability::bus_info);
56 }
57 unsigned int device_caps() const
58 {
59 return capabilities & V4L2_CAP_DEVICE_CAPS
60 ? v4l2_capability::device_caps
61 : v4l2_capability::capabilities;
62 }
63 bool isMultiplanar() const
64 {
65 return device_caps() & (V4L2_CAP_VIDEO_CAPTURE_MPLANE |
66 V4L2_CAP_VIDEO_OUTPUT_MPLANE |
67 V4L2_CAP_VIDEO_M2M_MPLANE);
68 }
69 bool isCapture() const
70 {
71 return device_caps() & (V4L2_CAP_VIDEO_CAPTURE |
72 V4L2_CAP_VIDEO_CAPTURE_MPLANE |
73 V4L2_CAP_META_CAPTURE);
74 }
75 bool isOutput() const
76 {
77 return device_caps() & (V4L2_CAP_VIDEO_OUTPUT |
78 V4L2_CAP_VIDEO_OUTPUT_MPLANE |
79 V4L2_CAP_META_OUTPUT);
80 }
81 bool isVideo() const
82 {
83 return device_caps() & (V4L2_CAP_VIDEO_CAPTURE |
84 V4L2_CAP_VIDEO_CAPTURE_MPLANE |
85 V4L2_CAP_VIDEO_OUTPUT |
86 V4L2_CAP_VIDEO_OUTPUT_MPLANE);
87 }
88 bool isM2M() const
89 {
90 return device_caps() & (V4L2_CAP_VIDEO_M2M |
91 V4L2_CAP_VIDEO_M2M_MPLANE);
92 }
93 bool isMeta() const
94 {
95 return device_caps() & (V4L2_CAP_META_CAPTURE |
96 V4L2_CAP_META_OUTPUT);
97 }
98 bool isVideoCapture() const
99 {
100 return isVideo() && isCapture();
101 }
102 bool isVideoOutput() const
103 {
104 return isVideo() && isOutput();
105 }
106 bool isMetaCapture() const
107 {
108 return isMeta() && isCapture();
109 }
110 bool isMetaOutput() const
111 {
112 return isMeta() && isOutput();
113 }
114 bool hasStreaming() const
115 {
116 return device_caps() & V4L2_CAP_STREAMING;
117 }
119 {
120 return device_caps() & V4L2_CAP_IO_MC;
121 }
122};
123
125{
126public:
127 V4L2BufferCache(unsigned int numEntries);
128 V4L2BufferCache(const std::vector<std::unique_ptr<FrameBuffer>> &buffers);
130
131 bool isEmpty() const;
132 int get(const FrameBuffer &buffer);
133 void put(unsigned int index);
134
135private:
136 class Entry
137 {
138 public:
139 Entry();
140 Entry(bool free, uint64_t lastUsed, const FrameBuffer &buffer);
141
142 bool operator==(const FrameBuffer &buffer) const;
143
144 bool free_;
145 uint64_t lastUsed_;
146
147 private:
148 struct Plane {
149 Plane(const FrameBuffer::Plane &plane)
150 : fd(plane.fd.get()), length(plane.length)
151 {
152 }
153
154 int fd;
155 unsigned int length;
156 };
157
158 std::vector<Plane> planes_;
159 };
160
161 std::atomic<uint64_t> lastUsedCounter_;
162 std::vector<Entry> cache_;
163 /* \todo Expose the miss counter through an instrumentation API. */
164 unsigned int missCounter_;
165};
166
168{
169public:
170 struct Plane {
171 uint32_t size = 0;
172 uint32_t bpl = 0;
173 };
174
177 std::optional<ColorSpace> colorSpace;
178
179 std::array<Plane, 3> planes;
180 unsigned int planesCount = 0;
181
182 const std::string toString() const;
183};
184
185std::ostream &operator<<(std::ostream &out, const V4L2DeviceFormat &f);
186
188{
189public:
190 using Formats = std::map<V4L2PixelFormat, std::vector<SizeRange>>;
191
192 explicit V4L2VideoDevice(const std::string &deviceNode);
193 explicit V4L2VideoDevice(const MediaEntity *entity);
195
196 int open();
197 int open(SharedFD handle, enum v4l2_buf_type type);
198 void close();
199
200 const char *driverName() const { return caps_.driver(); }
201 const char *deviceName() const { return caps_.card(); }
202 const char *busName() const { return caps_.bus_info(); }
203
204 const V4L2Capability &caps() const { return caps_; }
205
206 int getFormat(V4L2DeviceFormat *format);
207 int tryFormat(V4L2DeviceFormat *format);
208 int setFormat(V4L2DeviceFormat *format);
209 Formats formats(uint32_t code = 0);
210
211 int getSelection(unsigned int target, Rectangle *rect);
212 int setSelection(unsigned int target, Rectangle *rect);
213
214 int allocateBuffers(unsigned int count,
215 std::vector<std::unique_ptr<FrameBuffer>> *buffers);
216 int exportBuffers(unsigned int count,
217 std::vector<std::unique_ptr<FrameBuffer>> *buffers);
218 int importBuffers(unsigned int count);
219 int releaseBuffers();
220
221 int queueBuffer(FrameBuffer *buffer);
223
224 int streamOn();
225 int streamOff();
226
229
230 static std::unique_ptr<V4L2VideoDevice>
231 fromEntityName(const MediaDevice *media, const std::string &entity);
232
233 V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const;
234
235protected:
236 std::string logPrefix() const override;
237
238private:
240
241 enum class State {
242 Streaming,
243 Stopping,
244 Stopped,
245 };
246
247 int initFormats();
248
249 int getFormatMeta(V4L2DeviceFormat *format);
250 int trySetFormatMeta(V4L2DeviceFormat *format, bool set);
251
252 int getFormatMultiplane(V4L2DeviceFormat *format);
253 int trySetFormatMultiplane(V4L2DeviceFormat *format, bool set);
254
255 int getFormatSingleplane(V4L2DeviceFormat *format);
256 int trySetFormatSingleplane(V4L2DeviceFormat *format, bool set);
257
258 std::vector<V4L2PixelFormat> enumPixelformats(uint32_t code);
259 std::vector<SizeRange> enumSizes(V4L2PixelFormat pixelFormat);
260
261 int requestBuffers(unsigned int count, enum v4l2_memory memoryType);
262 int createBuffers(unsigned int count,
263 std::vector<std::unique_ptr<FrameBuffer>> *buffers);
264 std::unique_ptr<FrameBuffer> createBuffer(unsigned int index);
265 UniqueFD exportDmabufFd(unsigned int index, unsigned int plane);
266
267 void bufferAvailable();
268 FrameBuffer *dequeueBuffer();
269
270 void watchdogExpired();
271
272 template<typename T>
273 static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
274
275 V4L2Capability caps_;
276 V4L2DeviceFormat format_;
277 const PixelFormatInfo *formatInfo_;
278 std::unordered_set<V4L2PixelFormat> pixelFormats_;
279
280 enum v4l2_buf_type bufferType_;
281 enum v4l2_memory memoryType_;
282
283 V4L2BufferCache *cache_;
284 std::map<unsigned int, FrameBuffer *> queuedBuffers_;
285
286 EventNotifier *fdBufferNotifier_;
287
288 State state_;
289 std::optional<unsigned int> firstFrame_;
290
291 Timer watchdog_;
292 utils::Duration watchdogDuration_;
293};
294
296{
297public:
298 V4L2M2MDevice(const std::string &deviceNode);
300
301 int open();
302 void close();
303
304 V4L2VideoDevice *output() { return output_; }
305 V4L2VideoDevice *capture() { return capture_; }
306
307private:
308 std::string deviceNode_;
309
310 V4L2VideoDevice *output_;
311 V4L2VideoDevice *capture_;
312};
313
314} /* namespace libcamera */
Utilities to help constructing class interfaces.
#define LIBCAMERA_DISABLE_COPY(klass)
Disable copy construction and assignment of the klass.
Definition class.h:27
Notify of activity on a file descriptor.
Definition event_notifier.h:20
Frame buffer data and its associated dynamic metadata.
Definition framebuffer.h:49
The MediaDevice represents a Media Controller device with its full graph of connected objects.
Definition media_device.h:25
The MediaEntity represents an entity in the media graph.
Definition media_object.h:97
Information about pixel formats.
Definition formats.h:21
libcamera image pixel format
Definition pixel_format.h:17
Describe a rectangle's position and dimensions.
Definition geometry.h:243
RAII-style wrapper for file descriptors.
Definition shared_fd.h:17
int get() const
Retrieve the numerical file descriptor.
Definition shared_fd.h:30
Generic signal and slot communication mechanism.
Definition signal.h:39
Describe a two-dimensional size.
Definition geometry.h:53
Single-shot timer interface.
Definition timer.h:22
unique_ptr-like wrapper for a file descriptor
Definition unique_fd.h:18
Hot cache of associations between V4L2 buffer indexes and FrameBuffer.
Definition v4l2_videodevice.h:125
V4L2BufferCache(unsigned int numEntries)
Create an empty cache with numEntries entries.
Definition v4l2_videodevice.cpp:174
int get(const FrameBuffer &buffer)
Find the best V4L2 buffer for a FrameBuffer.
Definition v4l2_videodevice.cpp:229
bool isEmpty() const
Check if all the entries in the cache are unused.
Definition v4l2_videodevice.cpp:206
void put(unsigned int index)
Mark buffer index as free in the cache.
Definition v4l2_videodevice.cpp:271
The V4L2 video device image format and sizes.
Definition v4l2_videodevice.h:168
V4L2PixelFormat fourcc
The fourcc code describing the pixel encoding scheme.
Definition v4l2_videodevice.h:175
const std::string toString() const
Assemble and return a string describing the format.
Definition v4l2_videodevice.cpp:432
unsigned int planesCount
The number of valid data planes.
Definition v4l2_videodevice.h:180
std::optional< ColorSpace > colorSpace
The color space of the pixels.
Definition v4l2_videodevice.h:177
std::array< Plane, 3 > planes
The per-plane memory size information.
Definition v4l2_videodevice.h:179
Size size
The image size in pixels.
Definition v4l2_videodevice.h:176
const std::string & deviceNode() const
Retrieve the device node path.
Definition v4l2_device.h:44
V4L2Device(const std::string &deviceNode)
Construct a V4L2Device.
Definition v4l2_device.cpp:59
void close()
Close the memory-to-memory device, releasing any resources acquired by open()
Definition v4l2_videodevice.cpp:2221
V4L2VideoDevice * output()
Retrieve the output V4L2VideoDevice instance.
Definition v4l2_videodevice.h:304
V4L2VideoDevice * capture()
Retrieve the capture V4L2VideoDevice instance.
Definition v4l2_videodevice.h:305
int open()
Open a V4L2 Memory to Memory device.
Definition v4l2_videodevice.cpp:2184
V4L2M2MDevice(const std::string &deviceNode)
Create a new V4L2M2MDevice from the deviceNode.
Definition v4l2_videodevice.cpp:2163
V4L2 pixel format FourCC wrapper.
Definition v4l2_pixelformat.h:24
V4L2VideoDevice object and API.
Definition v4l2_videodevice.h:188
int importBuffers(unsigned int count)
Prepare the device to import count buffers.
Definition v4l2_videodevice.cpp:1563
int releaseBuffers()
Release resources allocated by allocateBuffers() or importBuffers()
Definition v4l2_videodevice.cpp:1591
int tryFormat(V4L2DeviceFormat *format)
Try an image format on the V4L2 video device.
Definition v4l2_videodevice.cpp:830
int allocateBuffers(unsigned int count, std::vector< std::unique_ptr< FrameBuffer > > *buffers)
Allocate and export buffers from the video device.
Definition v4l2_videodevice.cpp:1344
std::string logPrefix() const override
Retrieve a string to be prefixed to the log message.
Definition v4l2_videodevice.cpp:792
std::map< V4L2PixelFormat, std::vector< SizeRange > > Formats
A map of supported V4L2 pixel formats to frame sizes.
Definition v4l2_videodevice.h:190
void setDequeueTimeout(utils::Duration timeout)
Set the dequeue timeout value.
Definition v4l2_videodevice.cpp:2042
int open()
Open the V4L2 video device node and query its capabilities.
Definition v4l2_videodevice.cpp:569
Signal< FrameBuffer * > bufferReady
A Signal emitted when a framebuffer completes.
Definition v4l2_videodevice.h:222
const char * busName() const
Retrieve the location of the device in the system.
Definition v4l2_videodevice.h:202
int streamOn()
Start the video stream.
Definition v4l2_videodevice.cpp:1955
int queueBuffer(FrameBuffer *buffer)
Queue a buffer to the video device.
Definition v4l2_videodevice.cpp:1621
V4L2VideoDevice(const std::string &deviceNode)
Construct a V4L2VideoDevice.
Definition v4l2_videodevice.cpp:534
int streamOff()
Stop the video stream.
Definition v4l2_videodevice.cpp:1988
int getFormat(V4L2DeviceFormat *format)
Retrieve the image format set on the V4L2 video device.
Definition v4l2_videodevice.cpp:803
int getSelection(unsigned int target, Rectangle *rect)
Get the selection rectangle for target.
Definition v4l2_videodevice.cpp:1226
int exportBuffers(unsigned int count, std::vector< std::unique_ptr< FrameBuffer > > *buffers)
Export buffers from the video device.
Definition v4l2_videodevice.cpp:1393
Signal dequeueTimeout
A Signal emitted when the dequeue watchdog timer expires.
Definition v4l2_videodevice.h:228
const char * driverName() const
Retrieve the name of the V4L2 device driver.
Definition v4l2_videodevice.h:200
void close()
Close the video device, releasing any resources acquired by open()
Definition v4l2_videodevice.cpp:755
const V4L2Capability & caps() const
Retrieve the device V4L2 capabilities.
Definition v4l2_videodevice.h:204
static std::unique_ptr< V4L2VideoDevice > fromEntityName(const MediaDevice *media, const std::string &entity)
Create a new video device instance from entity in media device media.
Definition v4l2_videodevice.cpp:2079
int setSelection(unsigned int target, Rectangle *rect)
Set a selection rectangle rect for target.
Definition v4l2_videodevice.cpp:1258
V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const
Convert PixelFormat to a V4L2PixelFormat supported by the device.
Definition v4l2_videodevice.cpp:2110
int setFormat(V4L2DeviceFormat *format)
Configure an image format on the V4L2 video device.
Definition v4l2_videodevice.cpp:856
const char * deviceName() const
Retrieve the name of the V4L2 video device.
Definition v4l2_videodevice.h:201
Helper class from std::chrono::duration that represents a time duration in nanoseconds with double pr...
Definition utils.h:370
Class and enums to represent color spaces.
Frame buffer handling.
Data structures related to geometric objects.
Types and helper functions to handle libcamera image formats.
Logging infrastructure.
Top-level libcamera namespace.
Definition backtrace.h:17
std::ostream & operator<<(std::ostream &out, const Point &p)
Insert a text representation of a Point into an output stream.
Definition geometry.cpp:91
libcamera pixel format
Signal & slot implementation.
A memory region to store a single plane of a frame.
Definition framebuffer.h:53
SharedFD fd
The dmabuf file descriptor.
Definition framebuffer.h:55
unsigned int length
The plane length in bytes.
Definition framebuffer.h:57
struct v4l2_capability object wrapper and helpers
Definition v4l2_videodevice.h:44
bool hasStreaming() const
Determine if the video device can perform Streaming I/O.
Definition v4l2_videodevice.h:114
const char * bus_info() const
Retrieve the location of the video device in the system.
Definition v4l2_videodevice.h:53
bool isVideoCapture() const
Identify if the video device captures images.
Definition v4l2_videodevice.h:98
bool isMultiplanar() const
Identify if the video device implements the V4L2 multiplanar APIs.
Definition v4l2_videodevice.h:63
bool isOutput() const
Identify if the video device outputs data.
Definition v4l2_videodevice.h:75
bool isMetaOutput() const
Identify if the video device outputs image meta-data.
Definition v4l2_videodevice.h:110
bool isMeta() const
Identify if the video device captures or outputs image meta-data.
Definition v4l2_videodevice.h:93
bool isMetaCapture() const
Identify if the video device captures image meta-data.
Definition v4l2_videodevice.h:106
bool hasMediaController() const
Determine if the video device uses Media Controller to configure I/O.
Definition v4l2_videodevice.h:118
const char * driver() const
Retrieve the driver module name.
Definition v4l2_videodevice.h:45
bool isM2M() const
Identify if the device is a Memory-to-Memory device.
Definition v4l2_videodevice.h:88
bool isVideoOutput() const
Identify if the video device outputs images.
Definition v4l2_videodevice.h:102
bool isVideo() const
Identify if the video device captures or outputs images.
Definition v4l2_videodevice.h:81
bool isCapture() const
Identify if the video device captures data.
Definition v4l2_videodevice.h:69
unsigned int device_caps() const
Retrieve the capabilities of the video device.
Definition v4l2_videodevice.h:57
const char * card() const
Retrieve the video device card name.
Definition v4l2_videodevice.h:49
Per-plane memory size information.
Definition v4l2_videodevice.h:170
uint32_t size
The plane total memory size (in bytes)
Definition v4l2_videodevice.h:171
uint32_t bpl
The plane line stride (in bytes)
Definition v4l2_videodevice.h:172
Generic timer.
File descriptor wrapper that owns a file descriptor.
Miscellaneous utility functions.
Common base for V4L2 devices and subdevices.
V4L2 Pixel Format.