libcamera  v0.4.0
Supporting cameras in Linux since 2019
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 
22 #include <libcamera/base/class.h>
23 #include <libcamera/base/log.h>
24 #include <libcamera/base/signal.h>
25 #include <libcamera/base/timer.h>
27 #include <libcamera/base/utils.h>
28 
29 #include <libcamera/color_space.h>
30 #include <libcamera/framebuffer.h>
31 #include <libcamera/geometry.h>
32 #include <libcamera/pixel_format.h>
33 
37 
38 namespace libcamera {
39 
40 class EventNotifier;
41 class MediaDevice;
42 class MediaEntity;
43 
44 struct 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  }
118  bool hasMediaController() const
119  {
120  return device_caps() & V4L2_CAP_IO_MC;
121  }
122 };
123 
125 {
126 public:
127  V4L2BufferCache(unsigned int numEntries);
128  V4L2BufferCache(const std::vector<std::unique_ptr<FrameBuffer>> &buffers);
129  ~V4L2BufferCache();
130 
131  bool isEmpty() const;
132  int get(const FrameBuffer &buffer);
133  void put(unsigned int index);
134 
135 private:
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 {
169 public:
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 
185 std::ostream &operator<<(std::ostream &out, const V4L2DeviceFormat &f);
186 
188 {
189 public:
190  using Formats = std::map<V4L2PixelFormat, std::vector<SizeRange>>;
191 
192  explicit V4L2VideoDevice(const std::string &deviceNode);
193  explicit V4L2VideoDevice(const MediaEntity *entity);
194  ~V4L2VideoDevice();
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 
227  void setDequeueTimeout(utils::Duration timeout);
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 
235 protected:
236  std::string logPrefix() const override;
237 
238 private:
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 {
297 public:
298  V4L2M2MDevice(const std::string &deviceNode);
299  ~V4L2M2MDevice();
300 
301  int open();
302  void close();
303 
304  V4L2VideoDevice *output() { return output_; }
305  V4L2VideoDevice *capture() { return capture_; }
306 
307 private:
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.
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
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
std::optional< ColorSpace > colorSpace
The color space of the pixels.
Definition: v4l2_videodevice.h:177
unsigned int planesCount
The number of valid data planes.
Definition: v4l2_videodevice.h:180
Base class for V4L2VideoDevice and V4L2Subdevice.
Definition: v4l2_device.h:32
const std::string & deviceNode() const
Retrieve the device node path.
Definition: v4l2_device.h:44
Memory-to-Memory video device.
Definition: v4l2_videodevice.h:296
V4L2VideoDevice * capture()
Retrieve the capture V4L2VideoDevice instance.
Definition: v4l2_videodevice.h:305
void close()
Close the memory-to-memory device, releasing any resources acquired by open()
Definition: v4l2_videodevice.cpp:2221
int open()
Open a V4L2 Memory to Memory device.
Definition: v4l2_videodevice.cpp:2184
V4L2VideoDevice * output()
Retrieve the output V4L2VideoDevice instance.
Definition: v4l2_videodevice.h:304
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
std::map< V4L2PixelFormat, std::vector< SizeRange > > Formats
A map of supported V4L2 pixel formats to frame sizes.
Definition: v4l2_videodevice.h:190
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
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
const char * deviceName() const
Retrieve the name of the V4L2 video device.
Definition: v4l2_videodevice.h:201
std::string logPrefix() const override
Retrieve a string to be prefixed to the log message.
Definition: v4l2_videodevice.cpp:792
void setDequeueTimeout(utils::Duration timeout)
Set the dequeue timeout value.
Definition: v4l2_videodevice.cpp:2042
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
int open()
Open the V4L2 video device node and query its capabilities.
Definition: v4l2_videodevice.cpp:569
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
void close()
Close the video device, releasing any resources acquired by open()
Definition: v4l2_videodevice.cpp:755
const char * busName() const
Retrieve the location of the device in the system.
Definition: v4l2_videodevice.h:202
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
const V4L2Capability & caps() const
Retrieve the device V4L2 capabilities.
Definition: v4l2_videodevice.h:204
Signal< FrameBuffer * > bufferReady
A Signal emitted when a framebuffer completes.
Definition: v4l2_videodevice.h:222
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
Formats formats(uint32_t code=0)
Enumerate all pixel formats and frame sizes.
Definition: v4l2_videodevice.cpp:1103
int exportBuffers(unsigned int count, std::vector< std::unique_ptr< FrameBuffer >> *buffers)
Export buffers from the video device.
Definition: v4l2_videodevice.cpp:1393
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
bool operator==(const ColorSpace &lhs, const ColorSpace &rhs)
Compare color spaces for equality.
Definition: color_space.cpp:506
libcamera pixel format
Signal & slot implementation.
A memory region to store a single plane of a frame.
Definition: framebuffer.h:53
unsigned int length
The plane length in bytes.
Definition: framebuffer.h:57
SharedFD fd
The dmabuf file descriptor.
Definition: framebuffer.h:55
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
unsigned int device_caps() const
Retrieve the capabilities of the video device.
Definition: v4l2_videodevice.h:57
bool isVideoOutput() const
Identify if the video device outputs images.
Definition: v4l2_videodevice.h:102
bool isM2M() const
Identify if the device is a Memory-to-Memory device.
Definition: v4l2_videodevice.h:88
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
bool isOutput() const
Identify if the video device outputs data.
Definition: v4l2_videodevice.h:75
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 isMeta() const
Identify if the video device captures or outputs image meta-data.
Definition: v4l2_videodevice.h:93
bool isCapture() const
Identify if the video device captures data.
Definition: v4l2_videodevice.h:69
bool isMetaOutput() const
Identify if the video device outputs image meta-data.
Definition: v4l2_videodevice.h:110
const char * bus_info() const
Retrieve the location of the video device in the system.
Definition: v4l2_videodevice.h:53
const char * card() const
Retrieve the video device card name.
Definition: v4l2_videodevice.h:49
bool isVideo() const
Identify if the video device captures or outputs images.
Definition: v4l2_videodevice.h:81
const char * driver() const
Retrieve the driver module name.
Definition: v4l2_videodevice.h:45
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.