libcamera

https://libcamera.org/
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libcamera is a open-source camera support library for Linux that provides a unified API for camera...
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### start()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1CameraManager-members.html

Starts the camera manager service.

```APIDOC
## start()

### Description
Initializes and starts the camera manager, making cameras available for use.

### Method
member function

### Parameters
None
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1ipu3_1_1IPAIPU3-members.html

Starts the IPAIPU3 module.

```APIDOC
## start()

### Description
Starts the IPAIPU3 module.

### Method
start

### Endpoint
N/A

### Parameters
None

### Request Example
None

### Response
None

```

--------------------------------

### start()

Source: https://libcamera.org/api-html/classlibcamera_1_1CameraManager-members.html

Initializes and starts the camera manager service.

```APIDOC
## start()

### Description
Initializes the CameraManager and prepares it to detect and manage cameras.

### Method
`start()`

### Parameters
None.

### Returns
Void.
```

--------------------------------

### start

Source: https://libcamera.org/api-html/classlibcamera_1_1Camera.html

Starts capture from the camera, optionally applying a list of controls before starting. Once started, requests can be queued until the session is terminated.

```APIDOC
## start()

### Description
Starts capture from the camera, optionally providing a list of controls to apply before starting. Once the camera is started the application can queue requests to the camera to process and return to the application until the capture session is terminated with stop().

### Parameters
* **controls** (const ControlList *) - Controls to be applied before starting the Camera.

### Thread Safety
This function may only be called when the camera is in the Configured state, and shall be synchronized by the caller with other functions that affect the camera state.

### Returns
0 on success or a negative error code otherwise.

### Return values
* -ENODEV: The camera has been disconnected from the system.
* -EACCES: The camera is not in a state where it can be started.
```

--------------------------------

### Build and Install libcamera

Source: https://libcamera.org/getting-started.html

Clone the libcamera repository, set up the build environment with Meson, and install the library. Ensure you have the necessary build dependencies installed.

```bash
git clone https://git.libcamera.org/libcamera/libcamera.git
cd libcamera
meson setup build
ninja -C build install
```

--------------------------------

### start

Source: https://libcamera.org/api-html/functions_s.html

Starts camera operations.

```APIDOC
## start

### Description
Starts the operation of a libcamera::Camera or libcamera::CameraManager.

### Method
(Implicitly a member function)

### Endpoint
N/A (SDK function)

### Parameters
None explicitly documented in this snippet.

### Request Example
N/A

### Response
#### Success Response
(Typically void or a status code)

#### Response Example
N/A
```

--------------------------------

### start()

Source: https://libcamera.org/api-html/classlibcamera_1_1CameraManager.html

Starts the camera manager and enumerates all available devices. Once started, users can interact with cameras until the manager is stopped or a camera is unplugged. Returns 0 on success or a negative error code on failure.

```APIDOC
## start()

### Description
Start the camera manager and enumerate all devices in the system. Once the start has been confirmed the user is free to list and otherwise interact with cameras in the system until either the camera manager is stopped or the camera is unplugged from the system.

### Returns
0 on success or a negative error code otherwise
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/functions_func_s.html

Starts various components like cameras, converters, software ISPs, threads, or timers. Returns void.

```APIDOC
## start()

### Description
Starts various components.

### Parameters
- **camera** (libcamera::Camera) - The camera to start.
- **cameraManager** (libcamera::CameraManager) - The camera manager.
- **converter** (libcamera::Converter) - The converter to start.
- **ipaIpu3** (libcamera::ipa::ipu3::IPAIPU3) - The IPA IPU3 device.
- **pipelineHandler** (libcamera::PipelineHandler) - The pipeline handler.
- **process** (libcamera::Process) - The process to start.
- **softwareIsp** (libcamera::SoftwareIsp) - The software ISP.
- **thread** (libcamera::Thread) - The thread to start.
- **timer** (libcamera::Timer) - The timer to start.
- **v4l2M2MConverter** (libcamera::V4L2M2MConverter) - The V4L2 M2M converter.

```

--------------------------------

### start()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Thread.html

Starts the execution of the thread.

```APIDOC
## start()

### Description
Starts the thread.

### Method
void

### Parameters
None
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/functions_s.html

Starts various components like cameras, converters, pipelines, processes, or timers. Initiates operation.

```APIDOC
## start()

### Description
Starts various components.

### Method
N/A (Function Signature)

### Endpoint
N/A

### Parameters
N/A

### Request Example
N/A

### Response
- Returns: libcamera::Camera, libcamera::CameraManager, libcamera::Converter, libcamera::ipa::ipu3::IPAIPU3, libcamera::ipa::Pwl::Interval, libcamera::PipelineHandler, libcamera::Process, libcamera::SoftwareIsp, libcamera::Thread, libcamera::Timer, libcamera::V4L2M2MConverter
```

--------------------------------

### start()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1PipelineHandler.html

Starts capturing from a group of streams configured by configure(). The Camera class is the intended caller, indicating the application is ready to capture.

```APIDOC
## start()

### Description
Starts capturing from a group of streams configured by configure(). The Camera class is the intended caller, indicating the application is ready to capture.

### Parameters
- **_camera** (Camera *) - The camera to start
- **_controls** (const ControlList *) - Controls to be applied before starting the Camera

### Returns
0 on success or a negative error code otherwise.

### Thread Safety
This function is called from the CameraManager thread.
```

--------------------------------

### start()

Source: https://libcamera.org/api-html/functions_func_s.html

Starts camera operations or a camera manager. This function is overloaded for Camera and CameraManager.

```APIDOC
## start()

### Description
Starts camera operations or a camera manager.

### Method
(Not specified, likely a member function)

### Endpoint
(Not applicable)

### Parameters
(Not specified)

### Request Example
(Not applicable)

### Response
#### Success Response
(Not specified)

### Response Example
(Not specified)
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1SoftwareIsp-members.html

Starts the software ISP processing.

```APIDOC
## start

### Description
Starts the software ISP processing.

### Signature
start()
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2M2MConverter-members.html

Starts the V4L2M2MConverter. This method should be called before any conversion operations.

```APIDOC
## start

### Description
Starts the V4L2M2MConverter.

### Method
virtual void start()

### Parameters
None
```

--------------------------------

### CameraManager::start()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1CameraManager.html

Starts the camera manager and enumerates all devices in the system. After starting, applications can interact with cameras.

```APIDOC
## start()

### Description
Start the camera manager and enumerate all devices in the system. Once the start has been confirmed the user is free to list and otherwise interact with cameras in the system until either the camera manager is stopped or the camera is unplugged from the system.

### Method
`int start()`

### Returns
0 on success or a negative error code otherwise.
```

--------------------------------

### Start Camera and Queue Requests

Source: https://libcamera.org/guides/application-developer.html

Start the camera device and queue all prepared requests to begin frame capture. This is typically done after connecting signals.

```cpp
camera->start();
for (std::unique_ptr<Request> &request : requests)
   camera->queueRequest(request.get());
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Camera.html

Starts the camera capture session, optionally applying a list of controls beforehand. Once started, requests can be queued for processing. This function requires the camera to be in the Configured state and needs caller synchronization.

```APIDOC
## start()

### Description
Starts the camera capture session, optionally applying a list of controls beforehand. Once started, requests can be queued for processing. This function requires the camera to be in the Configured state and needs caller synchronization.

### Method
`int libcamera::Camera::start(const ControlList * _controls_ = nullptr)`

### Parameters
*   `_controls_` (const ControlList *) - Optional controls to be applied before starting the Camera.

### Returns
0 on success or a negative error code otherwise.

### Return values
*   -ENODEV: The camera has been disconnected from the system.
*   -EACCES: The camera is not in a state where it can be started.
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Converter.html

Starts the converter streaming operation.

```APIDOC
## start()

### Description
Start the converter streaming operation.

### Returns
An integer representing the status of the operation.
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/structlibcamera_1_1ipa_1_1Pwl_1_1Interval-members.html

The starting point of the interval.

```APIDOC
## start

### Description
Represents the starting value of the interval.
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1SoftwareIsp.html

Starts the Software ISP streaming operation.

```APIDOC
## start

### Description
Starts the Software ISP streaming operation.

### Returns
- **int** - An integer status code indicating success or failure.
```

--------------------------------

### Import Buffers in Pipeline Handler Start

Source: https://libcamera.org/guides/pipeline-handler.html

Implement the `start()` function to import the required number of buffers for the stream. This prepares the video device to use memory buffers exported as dma-buf file descriptors.

```cpp
VividCameraData *data = cameraData(camera);
unsigned int count = data->stream_.configuration().bufferCount;

int ret = data->video_->importBuffers(count);
if (ret < 0)
      return ret;

return 0;
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1PipelineHandler.html

Starts capturing from a group of streams with the specified controls. This is a pure virtual function.

```APIDOC
## int start(Camera *camera, const ControlList *controls)

### Description
Start capturing from a group of streams.

### Parameters
- **camera** (Camera *) - The camera to start capturing from.
- **controls** (const ControlList *) - A list of controls to apply during capture.
```

--------------------------------

### CameraManager::start

Source: https://libcamera.org/api-html/camera__manager_8h_source.html

Starts the camera manager, initializing it for camera operations.

```APIDOC
## start

### Description
Start the camera manager.

### Method
int start()

### Returns
An integer representing the status of the operation. 0 typically indicates success.
```

--------------------------------

### libcamera::controls::AfTriggerStart

Source: https://libcamera.org/api-html/control__ids_8h_source.html

Start an AF scan.

```APIDOC
## AfTriggerStart

### Description
Start an AF scan.

### Definition
control_ids.h:240
```

--------------------------------

### Initialize and Start Camera Manager

Source: https://libcamera.org/guides/application-developer.html

Creates and starts a CameraManager instance. This manager is essential for enumerating and interacting with cameras in the system. It should be unique and managed for the application's lifetime.

```cpp
std::unique_ptr<CameraManager> cm = std::make_unique<CameraManager>();
cm->start();

```

--------------------------------

### ControlList Usage Example

Source: https://libcamera.org/api-html/controls_8h.html

Demonstrates how to set and get control values using the ControlList within a Request object. The ControlList automatically deduces data types for set and get operations.

```cpp
Request *req = ...;
ControlList &controls = req->controls();
controls->set(controls::AwbEnable, false);
controls->set(controls::ManualExposure, 1000);
...
int32_t exposure = controls->get(controls::ManualExposure);
```

--------------------------------

### libcamera::CameraConfiguration::begin()

Source: https://libcamera.org/api-html/functions_b.html

Returns the beginning of the configuration.

```APIDOC
## begin()

### Description
Returns the beginning of the configuration.

### Method
(Not specified, likely a member function)

### Endpoint
(Not applicable, SDK function)

### Parameters
None

### Response
- **libcamera::CameraConfiguration**: The configuration object.
- **libcamera::ControlList**: The control list associated with the configuration.
```

--------------------------------

### begin()

Source: https://libcamera.org/api-html/functions_func_b.html

Initializes or begins a process, returning a CameraConfiguration or ControlList.

```APIDOC
## begin()

### Description
Initializes or begins a process.

### Returns
- libcamera::CameraConfiguration
- libcamera::ControlList
```

--------------------------------

### ControlList Usage Example

Source: https://libcamera.org/api-html/controls_8h.html

Demonstrates how to interact with controls using the ControlList, including setting and getting control values. The ControlList automatically handles data type deduction for common controls.

```APIDOC
## ControlList Operations

### Description
This section illustrates the typical usage of `ControlList` for managing camera controls within a `Request` object.

### Usage
```c++
#include <libcamera/request.h>
#include <libcamera/controls.h>

// Assume 'req' is a pointer to a valid Request object
Request *req = ...;
ControlList &controls = req->controls();

// Set a control value (e.g., Auto White Balance Enable)
controls.set(libcamera::controls::AwbEnable, false);

// Set another control value (e.g., Manual Exposure)
controls.set(libcamera::controls::ManualExposure, 1000);

// Get a control value (e.g., Manual Exposure)
int32_t exposure = controls.get(libcamera::controls::ManualExposure);

// The get() and set() methods automatically deduce the data type.
```

### Key Classes
- `libcamera::ControlList`: Manages a collection of controls and their values for an object.
- `libcamera::ControlId`: Represents the static metadata for a control.
- `libcamera::Request`: Contains the `ControlList` for a camera request.
```

--------------------------------

### startFrame

Source: https://libcamera.org/internal-api-html/functions_func_s.html

Starts a frame for CPU statistics. Returns void.

```APIDOC
## startFrame()

### Description
Starts a frame for CPU statistics.

### Parameters
- **swStatsCpu** (libcamera::SwStatsCpu) - The CPU statistics object.

```

--------------------------------

### Start Video Device Stream

Source: https://libcamera.org/guides/pipeline-handler.html

Complete the `start` function implementation by calling `streamOn()` to prepare the video device for capture operations. If the call fails, release any buffers and propagate the error.

```cpp
ret = data->video_->streamOn();
if (ret < 0) {
       data->video_->releaseBuffers();
       return ret;
}

return 0;
```

--------------------------------

### init()

Source: https://libcamera.org/internal-api-html/functions_i.html

Initializes various Libcamera components including CameraLens, DeviceEnumerator, IPA algorithms, and MediaPipeline.

```APIDOC
## init()

### Description
Initializes various Libcamera components.

### Method
N/A (Method signature)

### Endpoint
N/A

### Parameters
None

### Response
Returns one of the following types: libcamera::CameraLens, libcamera::DeviceEnumerator, libcamera::ipa::Algorithm< _Module >, libcamera::ipa::AwbAlgorithm, libcamera::ipa::AwbBayes, libcamera::ipa::AwbGrey, libcamera::ipa::ipu3::algorithms::Agc, libcamera::ipa::ipu3::IPAIPU3, libcamera::MediaPipeline
```

--------------------------------

### init()

Source: https://libcamera.org/internal-api-html/functions_func_i.html

Initializes various libcamera components.

```APIDOC
## init()

### Description
Initializes CameraLens, DeviceEnumerator, IPA modules, or MediaPipeline.

### Signature
`init() : libcamera::CameraLens , libcamera::DeviceEnumerator , libcamera::ipa::Algorithm< _Module > , libcamera::ipa::AwbAlgorithm , libcamera::ipa::AwbBayes , libcamera::ipa::AwbGrey , libcamera::ipa::ipu3::algorithms::Agc , libcamera::ipa::ipu3::IPAIPU3 , libcamera::MediaPipeline`
```

--------------------------------

### libcamera::ipa::Pwl::Interval::start

Source: https://libcamera.org/internal-api-html/pwl_8h_source.html

The start of the interval.

```APIDOC
## libcamera::ipa::Pwl::Interval::start

### Description
Start of the interval.

### Field
double start

### Definition
pwl.h:42
```

--------------------------------

### Build and Run libcamera Cam Utility

Source: https://libcamera.org/guides/pipeline-handler.html

Rebuild the project using ninja and run the `cam` utility with specific log levels to test device matching and observe debug output.

```bash
ninja -C build
LIBCAMERA_LOG_LEVELS=Pipeline,VIVID:0 ./build/src/cam/cam -l
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1ipu3_1_1IPAIPU3-members.html

Initializes the IPAIPU3 module with sensor and settings information.

```APIDOC
## init(const IPASettings &settings, const IPACameraSensorInfo &sensorInfo, const ControlInfoMap &sensorControls, ControlInfoMap *ipaControls)

### Description
Initializes the IPAIPU3 module with sensor and settings information.

### Method
init

### Endpoint
N/A

### Parameters
* **settings** (const IPASettings &) - The IPA settings.
* **sensorInfo** (const IPACameraSensorInfo &) - Information about the camera sensor.
* **sensorControls** (const ControlInfoMap &) - Controls from the sensor.
* **ipaControls** (ControlInfoMap *) - A pointer to a map for IPA controls.

### Request Example
None

### Response
None

```

--------------------------------

### start (deadline)

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Timer.html

Starts or restarts the timer with a specific deadline.

```APIDOC
## start (deadline)

### Description
Starts or restarts the timer with a _deadline_.

### Signature
void start(std::chrono::steady_clock::time_point deadline)

### Parameters
* **deadline** (std::chrono::steady_clock::time_point) - The specific point in time when the timer should expire.
```

--------------------------------

### start (duration)

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Timer.html

Starts or restarts the timer with a specified timeout duration.

```APIDOC
## start (duration)

### Description
Starts or restarts the timer with a timeout of _duration_.

### Signature
void start(std::chrono::milliseconds duration)

### Parameters
* **duration** (std::chrono::milliseconds) - The duration for the timer to run before timing out.
```

--------------------------------

### Format Get and Set

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2Subdevice.html

Functions to get and set the image format.

```APIDOC
## getFormat(const Stream &stream, V4L2SubdeviceFormat *format, Whence whence=ActiveFormat)

### Description
Retrieve the image format set on one of the V4L2 subdevice streams.

### Parameters
* **stream** (const Stream &) - The stream to get the format from.
* **format** (V4L2SubdeviceFormat *) - Pointer to a V4L2SubdeviceFormat structure to store the format.
* **whence** (Whence) - Specifies whether to get the active or default format (default is ActiveFormat).
```

```APIDOC
## getFormat(unsigned int pad, V4L2SubdeviceFormat *format, Whence whence=ActiveFormat)

### Description
Retrieve the image format set on one of the V4L2 subdevice pads.

### Parameters
* **pad** (unsigned int) - The pad to get the format from.
* **format** (V4L2SubdeviceFormat *) - Pointer to a V4L2SubdeviceFormat structure to store the format.
* **whence** (Whence) - Specifies whether to get the active or default format (default is ActiveFormat).
```

```APIDOC
## setFormat(const Stream &stream, V4L2SubdeviceFormat *format, Whence whence=ActiveFormat)

### Description
Set an image format on one of the V4L2 subdevice pads.

### Parameters
* **stream** (const Stream &) - The stream to set the format on.
* **format** (V4L2SubdeviceFormat *) - Pointer to a V4L2SubdeviceFormat structure containing the desired format.
* **whence** (Whence) - Specifies whether to set the active or default format (default is ActiveFormat).
```

```APIDOC
## setFormat(unsigned int pad, V4L2SubdeviceFormat *format, Whence whence=ActiveFormat)

### Description
Set an image format on one of the V4L2 subdevice pads.

### Parameters
* **pad** (unsigned int) - The pad to set the format on.
* **format** (V4L2SubdeviceFormat *) - Pointer to a V4L2SubdeviceFormat structure containing the desired format.
* **whence** (Whence) - Specifies whether to set the active or default format (default is ActiveFormat).
```

--------------------------------

### CameraManager::Private::start

Source: https://libcamera.org/internal-api-html/internal_2camera__manager_8h_source.html

Starts the camera manager, initializing internal components and preparing for camera operations.

```APIDOC
## start

### Description
Starts the camera manager, initializing internal components and preparing for camera operations.

### Method
`int start()`

### Parameters
None

### Returns
An integer status code indicating success or failure.
```

--------------------------------

### ControlValue Get and Set

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ControlValue.html

Methods for getting and setting the control value.

```APIDOC
## get()

### Description
Get the control value.

### Method
template<typename T >
T ControlValue::get() const
```

```APIDOC
## set(const T &value)

### Description
Set the control value to _value_.

### Method
template<typename T >
void ControlValue::set(const T &value)
```

--------------------------------

### get<T>()

Source: https://libcamera.org/api-html/classlibcamera_1_1ControlValue.html

Gets the control value, returning it as an instance of type T.

```APIDOC
## get<typename T>() const

### Description
Get the control value. This function returns the contained value as an instance of _T_. If the ControlValue instance stores a single value, the type _T_ shall match the stored value type(). If the instance stores an array of values, the type _T_ should be equal to Span<const R>, and the type _R_ shall match the stored value type(). The behaviour is undefined otherwise. Note that a ControlValue instance that stores a non-array value is not equivalent to an instance that stores an array value containing a single element. The latter shall be accessed through a Span<const R> type, while the former shall be accessed through a type _T_ corresponding to type().

### Returns
T - The control value.
```

--------------------------------

### Initialize V4L2 Video Device

Source: https://libcamera.org/guides/pipeline-handler.html

Implement the init() function to create and open a V4L2 video device. This example opens a specific capture device named 'vivid-000-vid-cap'. Returns -ENODEV on failure.

```cpp
int VividCameraData::init()
{
       video_ = new V4L2VideoDevice(media_->getEntityByName("vivid-000-vid-cap"));
       if (video_->open())
             return -ENODEV;

       return 0;
}

```

--------------------------------

### Frame Start Event

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2Subdevice.html

Functions to check for and enable/disable frame start event notifications.

```APIDOC
## supportsFrameStartEvent()

### Description
Check if frame start event is supported.

### Method
bool

### Return Value
Returns true if frame start event is supported, false otherwise.
```

```APIDOC
## setFrameStartEnabled(bool enable)

### Description
Enable or disable frame start event notification.

### Parameters
* **enable** (bool) - True to enable, false to disable.
```

--------------------------------

### prepare

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1ipu3_1_1algorithms_1_1ToneMapping.html

Prepares the IPU3 parameter structure for tone mapping and enables gamma control.

```APIDOC
## prepare()

### Description
Fill in the parameter structure, and enable gamma control.

### Method
`void prepare(IPAContext &context, const uint32_t frame, IPAFrameContext &frameContext, ipu3_uapi_params *params)`

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- None

### Parameters
- **context** (IPAContext &) - Required - The shared IPA context.
- **frame** (const uint32_t) - Required - The frame context sequence number.
- **frameContext** (IPAFrameContext &) - Required - The FrameContext for this frame.
- **params** (ipu3_uapi_params *) - Output - The IPU3 parameters. This structure will be populated with the tone mapping look up table and gamma control settings.

### Response
- This method does not return a value.

### Request Example
```APIDOC
prepare(ipa_context, frame_number, frame_context, ipu3_params)
```

### Response Example
```APIDOC
// No return value
```
```

--------------------------------

### libcamera::FrameMetadata::FrameStartup

Source: https://libcamera.org/api-html/framebuffer_8h_source.html

Indicates the startup of a frame.

```APIDOC
## libcamera::FrameMetadata::FrameStartup

### Definition
framebuffer.h:29
```

--------------------------------

### start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ThreadMain.html

Starts the execution of the thread. This will typically call the run() method in a new thread of execution.

```APIDOC
## void start ()

### Description
Start the thread. More...

### Method
void
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1ipu3_1_1algorithms_1_1BlackLevelCorrection.html

Initializes the Algorithm with tuning data.

```APIDOC
## init

### Description
Initialize the Algorithm with tuning data.

### Method
int

### Signature
virtual int init ([[maybe_unused]] typename Module::Context &context, [[maybe_unused]] const YamlObject &tuningData)

### Parameters
- **context** (typename Module::Context &) - The module context.
- **tuningData** (const YamlObject &) - The tuning data in YAML format.
```

--------------------------------

### open()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2M2MDevice.html

Opens a V4L2 Memory to Memory device. This method initializes the device node and prepares two V4L2VideoDevice instances for buffer queue management.

```APIDOC
## open()

### Description
Open a V4L2 Memory to Memory device. Open the device node and prepare the two V4L2VideoDevice instances to handle their respective buffer queues.

### Returns
0 on success or a negative error code otherwise
```

--------------------------------

### Enable/Disable Frame Start Event

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2Device.html

Enables or disables the notification of frame start events from the V4L2 device.

```APIDOC
## setFrameStartEnabled

### Description
Enable or disable frame start event notification.

### Method
int setFrameStartEnabled(bool enable)

### Parameters
* **enable** (bool) - `true` to enable frame start event notifications, `false` to disable.

### Returns
An integer status code. Typically 0 on success, negative on failure.
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1AwbGrey.html

Initializes the AWB Grey algorithm with the provided tuning data. It loads the color temperature curve from the tuning data; if none is available, it proceeds with a warning, and manual color temperature adjustments will not function.

```APIDOC
## init()

### Description
Initialize the algorithm with the given tuning data.

### Parameters
* **tuningData** (const YamlObject &) - The tuning data for the algorithm.

### Returns
0 on success, a negative error code otherwise.

### Implements
libcamera::ipa::AwbAlgorithm
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1AwbBayes-members.html

Initializes the AwbBayes algorithm with tuning data.

```APIDOC
## init

### Description
Initializes the AwbBayes algorithm with tuning data.

### Method
virtual override

### Endpoint
libcamera::ipa::AwbBayes::init(const YamlObject &tuningData)

### Parameters
- **tuningData** (const YamlObject &) - The tuning data to initialize with.

### Request Example
None

### Response
None
```

--------------------------------

### SensorRollingShutterSkew

Source: https://libcamera.org/api-html/control__ids_8h_source.html

Control to report the time between the start of exposure of the first row and the start of exposure of the last row.

```APIDOC
## SensorRollingShutterSkew

### Description
Control to report the time between the start of exposure of the first row and the start of exposure of the last row.

### Type
int64_t
```

--------------------------------

### IPAIPU3::start

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1ipu3_1_1IPAIPU3.html

Performs any processing required before the first frame is processed. This is typically used for one-time setup operations that need to occur after initialization but before any image data is handled.

```APIDOC
## IPAIPU3::start

### Description
Perform any processing required before the first frame.

### Signature
```cpp
int start()
```

### Returns
An integer status code indicating success or failure.
```

--------------------------------

### Check Frame Start Event Support

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2Device.html

Determines if the V4L2 device supports notifications for the start of frame capture.

```APIDOC
## supportsFrameStartEvent

### Description
Check if frame start event is supported.

### Method
bool supportsFrameStartEvent()

### Parameters
None

### Returns
`true` if the frame start event is supported, `false` otherwise.
```

--------------------------------

### Process::start

Source: https://libcamera.org/internal-api-html/process_8h_source.html

Starts a new process by forking and executing the specified path. Arguments and file descriptors can be provided.

```APIDOC
## start

### Description

Forks and execs a process, and closes specified file descriptors.

### Method

`int start(const std::string &path, Span<const std::string> args = {}, Span<const int> fds = {})`

### Parameters

- **path** (const std::string &) - The path to the executable.
- **args** (Span<const std::string>) - Optional. A span of strings representing the arguments to pass to the process.
- **fds** (Span<const int>) - Optional. A span of integers representing file descriptors to be closed after the process is started.
```

--------------------------------

### get() - Control ID

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ControlList.html

Gets the value of a control using its numerical ID. Behavior is undefined if the ID is not present.

```APIDOC
## get() [2/2]

### Description
Get the value of control _id_.

### Parameters
* **id** (unsigned int) - [in] - The control numerical ID

### Returns
The control value.

### Note
The behaviour is undefined if the control _id_ is not present in the list. Use ControlList::contains() to test for the presence of a control in the list before retrieving its value.
```

--------------------------------

### init()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1CameraLens-members.html

Initializes the camera lens.

```APIDOC
## init()

### Description
Performs the initialization process for the camera lens.

### Signature
init()
```

--------------------------------

### Example Debug Output

Source: https://libcamera.org/guides/pipeline-handler.html

This is an example of the expected debug output when the 'Vivid Device Identified' log message is triggered.

```text
DEBUG VIVID vivid.cpp:74 Vivid Device Identified
```

--------------------------------

### configure()

Source: https://libcamera.org/api-html/functions_c.html

Configures the camera with specified settings, preparing it for operation.

```APIDOC
## configure()

### Description
Configures the camera according to the provided settings. This prepares the camera for capturing images or video.

### Parameters
- **config** (CameraConfiguration) - The desired configuration for the camera.

### Class
libcamera::Camera
```

--------------------------------

### Variables starting with 'g'

Source: https://libcamera.org/internal-api-html/functions_vars_g.html

This section details variables found in libcamera, categorized by their namespace or class, that start with the letter 'g'.

```APIDOC
## Variables starting with 'g'

This section details variables found in libcamera, categorized by their namespace or class, that start with the letter 'g'.

### Namespace: libcamera::DebayerParams

*   **CcmColumn** : libcamera::DebayerParams::CcmColumn
*   **gammaLut** : libcamera::DebayerParams
*   **green** : libcamera::DebayerParams
*   **greenCcm** : libcamera::DebayerParams

### Namespace: libcamera::ipa::ipu3::IPAActiveState

*   **gain** : libcamera::ipa::ipu3::IPAActiveState
*   **gains** : libcamera::ipa::ipu3::IPAActiveState
*   **gamma** : libcamera::ipa::ipu3::IPAActiveState
*   **gammaCorrection** : libcamera::ipa::ipu3::IPAActiveState
*   **green** : libcamera::ipa::ipu3::IPAActiveState

### Namespace: libcamera::ipa::ipu3::algorithms::Accumulator

*   **green** : libcamera::ipa::ipu3::algorithms::Accumulator

### Namespace: libcamera::ipa::CameraSensorHelper

*   **gain_** : libcamera::ipa::CameraSensorHelper

### Namespace: libcamera::ipa::AwbResult

*   **gains** : libcamera::ipa::AwbResult

### Namespace: libcamera::CameraSensorProperties::SensorDelays

*   **gainDelay** : libcamera::CameraSensorProperties::SensorDelays

### Namespace: libcamera::ipa::ipu3::IPASessionConfiguration

*   **grid** : libcamera::ipa::ipu3::IPASessionConfiguration
```

--------------------------------

### createAlgorithms()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1Module.html

Creates and initializes algorithms based on provided YAML configuration data.

```APIDOC
## createAlgorithms()

### Description
Create algorithms from YAML configuration data.

This function iterates over the list of _algorithms_ parsed from the YAML configuration file, and instantiates and initializes the corresponding algorithms. The configuration data is expected to be correct, any error causes the function to fail and return immediately.

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- **_context_** (Context &) - Required - The IPA context.
- **_algorithms_** (const YamlObject &) - Required - Algorithms configuration data as a parsed YamlObject.

### Request Example
```json
{
  "_context_": "<IPA Context Object>",
  "_algorithms_": "<YAML Configuration Data>"
}
```

### Response
#### Success Response (0)
- **Return Value** (int) - 0 on success.

#### Error Response (-ve integer)
- **Return Value** (int) - A negative error code on failure.

### Response Example
```json
{
  "example": "0"
}
```
```

--------------------------------

### get() - Typed Control

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ControlList.html

Gets the value of a specific control type from the list. Can also be used to check for control presence.

```APIDOC
## get() [1/2]

### Description
Get the value of control _ctrl_.

Beside getting the value of a control, this function can also be used to check if a control is present in the ControlList by converting the returned std::optional<T> to bool (or calling its has_value() function).

### Parameters
* **ctrl** (const Control< T > &) - [in] - The control

### Returns
A std::optional<T> containing the control value, or std::nullopt if the control _ctrl_ is not present in the list.
```

--------------------------------

### Deduction Guide for scope_exit

Source: https://libcamera.org/internal-api-html/utils_8h_source.html

A deduction guide to help the compiler deduce the template argument for scope_exit when constructing it with a function object.

```cpp
template<typename EF>
scope_exit(EF) -> scope_exit<EF>;

```

--------------------------------

### SensorRollingShutterSkew

Source: https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html

Control to report the time between the start of exposure of the first row and the start of exposure of the last row. Currently identical to ANDROID_SENSOR_ROLLING_SHUTTER_SKEW.

```APIDOC
## Control SensorRollingShutterSkew

### Description
Control to report the time between the start of exposure of the first row and the start of exposure of the last row. Currently identical to ANDROID_SENSOR_ROLLING_SHUTTER_SKEW.

### Type
Control< int64_t >
```

--------------------------------

### begin()

Source: https://libcamera.org/internal-api-html/functions_func_b.html

Returns an iterator to the beginning of a container.

```APIDOC
## begin()

### Description
Returns an iterator pointing to the first element in the `libcamera::CameraConfiguration` or `libcamera::ControlList`.

### Method
N/A (member function)

### Endpoint
N/A

### Parameters
N/A

### Request Example
N/A

### Response
- **iterator** (iterator type) - An iterator to the beginning of the container.
```

--------------------------------

### libcamera::Camera::start

Source: https://libcamera.org/api-html/context.html

Starts the camera with optional controls. This function must be called when the camera is in the Configured state and requires caller synchronization.

```APIDOC
## start

### Description
Starts the camera with optional controls. This function may only be called when the camera is in the Configured state and shall be synchronized by the caller with other functions that affect the camera state.

### Method
start (const ControlList *controls=nullptr)

### Parameters
* **controls** (const ControlList *) - Optional list of controls to apply when starting. Defaults to nullptr.

### Response
None specified
```

--------------------------------

### FrameDuration

Source: https://libcamera.org/api-html/namespacelibcamera_1_1controls.html

Represents the instantaneous frame duration, from the start of exposure to the start of the next exposure, measured in microseconds. This control is intended for metadata reporting.

```APIDOC
## ◆ FrameDuration
libcamera::controls::FrameDuration

---

The instantaneous frame duration from start of frame exposure to start of next exposure, expressed in microseconds. This control is meant to be returned in metadata.
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1AwbAlgorithm-members.html

Initializes the algorithm with tuning data. This is a pure virtual function.

```APIDOC
## init

### Description
Initializes the algorithm with tuning data.

### Method
`virtual bool init(const YamlObject &tuningData) = 0`

### Parameters
* **tuningData** (`const YamlObject &`) - The tuning data for initialization.

### Returns
`true` if initialization was successful, `false` otherwise.
```

--------------------------------

### supportsFrameStartEvent

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1V4L2Device.html

Check if frame start event is supported. Note: This function may disable the frame start event as a side effect and should only be called during initialization.

```APIDOC
## supportsFrameStartEvent()

### Description
Check if frame start event is supported. Due to limitations in the kernel API, this function may disable the frame start event as a side effect. It should only be called during initialization, before enabling the frame start event with setFrameStartEnabled().

### Method Signature
`bool libcamera::V4L2Device::supportsFrameStartEvent()
`

### Returns
* **True** if frame start event is supported, **false** otherwise.
```

--------------------------------

### Enumerations Starting with 'b'

Source: https://libcamera.org/api-html/namespacemembers_eval.html

This section details enumeration members that start with the letter 'b', specifically related to image properties like Bayer patterns.

```APIDOC
## Enumerations Starting with 'b'

### Description
Details enumeration members starting with 'b'.

### Members
- **BGGR** : libcamera::properties::draft
```

--------------------------------

### create()

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1Camera.html

Creates a camera instance given a private data pointer, a unique camera ID, and a set of streams.

```APIDOC
## create()

### Description
Create a camera instance.

Parameters
     [in]| d| Camera private data
[in]| id| The ID of the camera device
[in]| streams| Array of streams the camera provides
The caller is responsible for guaranteeing a stable and unique camera ID matching the constraints described by Camera::id(). Parameters that are allocated dynamically at system startup, such as bus numbers that may be enumerated differently, are therefore not suitable to use in the ID.
Pipeline handlers that use a CameraSensor may use the CameraSensor::id() to generate an ID that satisfies the criteria of a stable and unique camera ID.

Returns
    A shared pointer to the newly created camera object
```

--------------------------------

### get() Member Function

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ControlValue.html

Documentation for the get() member function, which retrieves the control value as an instance of type T. Handles both single values and arrays.

```APIDOC
## ◆ get()
template<typename T >
| template< typename T > T libcamera::ControlValue::get  | ( | | ) |  const  
---|---|---|---|---
inline
Get the control value.
This function returns the contained value as an instance of _T_. If the ControlValue instance stores a single value, the type _T_ shall match the stored value type(). If the instance stores an array of values, the type _T_ should be equal to Span<const R>, and the type _R_ shall match the stored value type(). The behaviour is undefined otherwise.
Note that a ControlValue instance that stores a non-array value is not equivalent to an instance that stores an array value containing a single element. The latter shall be accessed through a Span<const R> type, while the former shall be accessed through a type _T_ corresponding to type().

Returns
    The control value

```

--------------------------------

### match

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1PipelineHandler.html

Matches media devices and creates camera instances. This is a pure virtual function and must be implemented by derived classes.

```APIDOC
## bool match(DeviceEnumerator *enumerator) const

### Description
Match media devices and create camera instances.

### Parameters
- **enumerator** (DeviceEnumerator *) - The device enumerator to use for matching.
```

--------------------------------

### Call IPA Functions

Source: https://libcamera.org/guides/ipa.html

Invoke IPA functions defined in the Main IPA interface after initialization and starting the IPA. Asynchronous functions must not be called before start().

```c++
ipa_->start();
int ret = ipa_->configure(sensorInfo_, streamConfig, entityControls, ipaConfig, &result);
ipa_->signalStatReady(RPi::BufferMask::STATS | static_cast<unsigned int>(index));

```

--------------------------------

### Class Definitions for Graph Example

Source: https://libcamera.org/internal-api-html/graph_legend.html

These C++ class definitions are used to generate an example inheritance graph. They demonstrate various inheritance types and template usage.

```cpp
/*! Invisible class because of truncation */
class Invisible { };
/*! Truncated class, inheritance relation is hidden */
class Truncated : public Invisible { };
/* Class not documented with doxygen comments */
class Undocumented { };
/*! Class that is inherited using public inheritance */
class PublicBase : public Truncated { };
/*! A template class */
template<class T> class Templ { };
/*! Class that is inherited using protected inheritance */
class ProtectedBase { };
/*! Class that is inherited using private inheritance */
class PrivateBase { };
/*! Class that is used by the Inherited class */
class Used { };
/*! Super class that inherits a number of other classes */
class Inherited : public PublicBase,
protected ProtectedBase,
private PrivateBase,
public Undocumented,
public Templ<int>
{
private:
Used *m_usedClass;
};
```

--------------------------------

### Set up GStreamer Development Environment

Source: https://libcamera.org/getting-started.html

Use this command to create a new shell with the GST_PLUGIN_PATH environment variable set for the GStreamer plugin.

```bash
meson devenv -C build

```

--------------------------------

### libcamera::CameraConfiguration::begin

Source: https://libcamera.org/internal-api-html/functions_b.html

Returns an iterator to the beginning of the camera configuration.

```APIDOC
## Function: libcamera::CameraConfiguration::begin()

### Description
Provides an iterator pointing to the beginning of the camera configuration elements.

### Signature
`iterator begin()`
```

--------------------------------

### Namespace Members starting with 'm'

Source: https://libcamera.org/api-html/namespacemembers_m.html

This section details various members within the libcamera namespaces that start with the letter 'm'. These include controls, properties, and their draft versions.

```APIDOC
## Namespace Members (m)

### Description
This section lists namespace members starting with 'm'.

### Members
- **MaxLatency** : `libcamera::controls::draft`
- **MeteringCentreWeighted** : `libcamera::controls`
- **MeteringCustom** : `libcamera::controls`
- **MeteringMatrix** : `libcamera::controls`
- **MeteringSpot** : `libcamera::controls`
- **Model** : `libcamera::properties`
- **MONO** : `libcamera::properties::draft`
```

--------------------------------

### init

Source: https://libcamera.org/internal-api-html/classlibcamera_1_1ipa_1_1AwbGrey-members.html

Initializes the AWB algorithm with tuning data.

```APIDOC
## init

### Description
Initializes the AWB algorithm with tuning data.

### Method
`init(const YamlObject &tuningData)`

### Endpoint
N/A

### Parameters
- **tuningData** (const YamlObject &): The tuning data in YamlObject format.

### Request Example
None

### Response
None
```

--------------------------------

### libcamera::controls::draft::SensorRollingShutterSkew

Source: https://libcamera.org/internal-api-html/control__ids_8h_source.html

Reports the time between the start of exposure of the first row and the start of exposure of the last row of the sensor. This is crucial for understanding rolling shutter effects.

```APIDOC
## libcamera::controls::draft::SensorRollingShutterSkew

### Description
Control to report the time between the start of exposure of the first row and the start of exposure o...

### Type
Control< int64_t >
```

--------------------------------

### Camera::start

Source: https://libcamera.org/internal-api-html/camera_8h_source.html

Starts the camera capture process. Optional controls can be provided to set initial parameters. Returns 0 on success, or a negative error code on failure.

```APIDOC
## Camera::start

### Description
Starts the camera capture process. Optional controls can be provided to set initial parameters. Returns 0 on success, or a negative error code on failure.

### Signature
```cpp
int start(const ControlList *controls = nullptr);
```
```

--------------------------------

### Compile and Run Application with Meson

Source: https://libcamera.org/guides/application-developer.html

Standard commands to build, compile, and run an application using the Meson build system. This sequence involves configuring the build, compiling the code, and then executing the application.

```bash
$ meson build
$ cd build
$ ninja
$ ./simple-cam

```

--------------------------------

### Class Members starting with 'n'

Source: https://libcamera.org/internal-api-html/functions_n.html

This section lists class members whose names start with the letter 'n'. It includes functions and enumerators across various libcamera classes.

```APIDOC
## name()

### Description
Returns the name of the object.

### Method
(Implicitly a member function)

### Parameters
None

### Returns
(Type varies based on context, e.g., libcamera::CameraControlValidator, libcamera::ControlId, etc.)

## names()

### Description
Returns a collection of names.

### Method
(Implicitly a member function)

### Parameters
None

### Returns
(Type varies, e.g., libcamera::ConverterFactoryBase)

## None

### Description
Represents a null or non-existent message.

### Class
libcamera::Message

## NormalExit

### Description
Indicates a normal process exit.

### Class
libcamera::Process

## NotExited

### Description
Indicates that a process has not yet exited.

### Class
libcamera::Process

## numElements()

### Description
Returns the number of elements in the control value.

### Method
(Implicitly a member function)

### Parameters
None

### Returns
(Type: integer)

## numPlanes()

### Description
Returns the number of planes for a given pixel format.

### Method
(Implicitly a member function)

### Parameters
None

### Returns
(Type: integer)
```

--------------------------------

### Enumerations Starting with 'c'

Source: https://libcamera.org/api-html/namespacemembers_eval.html

This section details enumeration members that start with the letter 'c', covering camera locations, color correction settings, connection types, and control types.

```APIDOC
## Enumerations Starting with 'c'

### Description
Details enumeration members starting with 'c'.

### Members
- **CameraLocationBack** : libcamera::properties
- **CameraLocationExternal** : libcamera::properties
- **CameraLocationFront** : libcamera::properties
- **ColorCorrectionAberrationFast** : libcamera::controls::draft
- **ColorCorrectionAberrationHighQuality** : libcamera::controls::draft
- **ColorCorrectionAberrationOff** : libcamera::controls::draft
- **ConnectionTypeAuto** : libcamera
- **ConnectionTypeBlocking** : libcamera
- **ConnectionTypeDirect** : libcamera
- **ConnectionTypeQueued** : libcamera
- **ConstraintCustom** : libcamera::controls
- **ConstraintHighlight** : libcamera::controls
- **ConstraintNormal** : libcamera::controls
- **ConstraintShadows** : libcamera::controls
- **ControlTypeBool** : libcamera
- **ControlTypeByte** : libcamera
- **ControlTypeFloat** : libcamera
- **ControlTypeInteger32** : libcamera
- **ControlTypeInteger64** : libcamera
- **ControlTypeNone** : libcamera
- **ControlTypeString** : libcamera
- **ControlTypeUnsigned16** : libcamera
- **ControlTypeUnsigned32** : libcamera
```
Tokens:
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