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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2018, Google Inc.
*
* camera.cpp - Camera device
*/
#include <libcamera/camera.h>
#include <array>
#include <atomic>
#include <iomanip>
#include <libcamera/base/log.h>
#include <libcamera/base/thread.h>
#include <libcamera/color_space.h>
#include <libcamera/framebuffer_allocator.h>
#include <libcamera/request.h>
#include <libcamera/stream.h>
#include "libcamera/internal/camera.h"
#include "libcamera/internal/camera_controls.h"
#include "libcamera/internal/formats.h"
#include "libcamera/internal/pipeline_handler.h"
#include "libcamera/internal/request.h"
/**
* \file libcamera/camera.h
* \brief Camera device handling
*
* \page camera-model Camera Model
*
* libcamera acts as a middleware between applications and camera hardware. It
* provides a solution to an unsolvable problem: reconciling applications,
* which need to run on different systems without dealing with device-specific
* details, and camera hardware, which exhibits a wide variety of features,
* limitations and architecture variations. In order to do so, it creates an
* abstract camera model that hides the camera hardware from applications. The
* model is designed to strike the right balance between genericity, to please
* generic applications, and flexibility, to expose even the most specific
* hardware features to the most demanding applications.
*
* In libcamera, a Camera is defined as a device that can capture frames
* continuously from a camera sensor and store them in memory. If supported by
* the device and desired by the application, the camera may store each
* captured frame in multiple copies, possibly in different formats and sizes.
* Each of these memory outputs of the camera is called a Stream.
*
* A camera contains a single image source, and separate camera instances
* relate to different image sources. For instance, a phone containing front
* and back image sensors will be modelled with two cameras, one for each
* sensor. When multiple streams can be produced from the same image source,
* all those streams are guaranteed to be part of the same camera.
*
* While not sharing image sources, separate cameras can share other system
* resources, such as ISPs. For this reason camera instances may not be fully
* independent, in which case usage restrictions may apply. For instance, a
* phone with a front and a back camera may not allow usage of the two cameras
* simultaneously.
*
* The camera model defines an implicit pipeline, whose input is the camera
* sensor, and whose outputs are the streams. Along the pipeline, the frames
* produced by the camera sensor are transformed by the camera into a format
* suitable for applications, with image processing that improves the quality
* of the captured frames. The camera exposes a set of controls that
* applications may use to manually control the processing steps. This
* high-level camera model is the minimum baseline that all cameras must
* conform to.
*
* \section camera-pipeline-model Pipeline Model
*
* Camera hardware differs in the supported image processing operations and the
* order in which they are applied. The libcamera pipelines abstract the
* hardware differences and expose a logical view of the processing operations
* with a fixed order. This offers low-level control of those operations to
* applications, while keeping application code generic.
*
* Starting from the camera sensor, a pipeline applies the following
* operations, in that order.
*
* - Pixel exposure
* - Analog to digital conversion and readout
* - Black level subtraction
* - Defective pixel correction
* - Lens shading correction
* - Spatial noise filtering
* - Per-channel gains (white balance)
* - Demosaicing (color filter array interpolation)
* - Color correction matrix (typically RGB to RGB)
* - Gamma correction
* - Color space transformation (typically RGB to YUV)
* - Cropping
* - Scaling
*
* Not all cameras implement all operations, and they are not necessarily
* implemented in the above order at the hardware level. The libcamera pipeline
* handlers translate the pipeline model to the real hardware configuration.
*
* \subsection digital-zoom Digital Zoom
*
* Digital zoom is implemented as a combination of the cropping and scaling
* stages of the pipeline. Cropping is controlled explicitly through the
* controls::ScalerCrop control, while scaling is controlled implicitly based
* on the crop rectangle and the output stream size. The crop rectangle is
* expressed relatively to the full pixel array size and indicates how the field
* of view is affected by the pipeline.
*/
namespace libcamera {
LOG_DECLARE_CATEGORY(Camera)
/**
* \class CameraConfiguration
* \brief Hold configuration for streams of the camera
* The CameraConfiguration holds an ordered list of stream configurations. It
* supports iterators and operates as a vector of StreamConfiguration instances.
* The stream configurations are inserted by addConfiguration(), and the
* at() function or operator[] return a reference to the StreamConfiguration
* based on its insertion index. Accessing a stream configuration with an
* invalid index results in undefined behaviour.
*
* CameraConfiguration instances are retrieved from the camera with
* Camera::generateConfiguration(). Applications may then inspect the
* configuration, modify it, and possibly add new stream configuration entries
* with addConfiguration(). Once the camera configuration satisfies the
* application, it shall be validated by a call to validate(). The validation
* implements "try" semantics: it adjusts invalid configurations to the closest
* achievable parameters instead of rejecting them completely. Applications
* then decide whether to accept the modified configuration, or try again with
* a different set of parameters. Once the configuration is valid, it is passed
* to Camera::configure().
*/
/**
* \enum CameraConfiguration::Status
* \brief Validity of a camera configuration
* \var CameraConfiguration::Valid
* The configuration is fully valid
* \var CameraConfiguration::Adjusted
* The configuration has been adjusted to a valid configuration
* \var CameraConfiguration::Invalid
* The configuration is invalid and can't be adjusted automatically
*/
/**
* \typedef CameraConfiguration::iterator
* \brief Iterator for the stream configurations in the camera configuration
*/
/**
* \typedef CameraConfiguration::const_iterator
* \brief Const iterator for the stream configuration in the camera
* configuration
*/
/**
* \brief Create an empty camera configuration
*/
CameraConfiguration::CameraConfiguration()
: transform(Transform::Identity), config_({})
{
}
CameraConfiguration::~CameraConfiguration()
{
}
/**
* \brief Add a stream configuration to the camera configuration
* \param[in] cfg The stream configuration
*/
void CameraConfiguration::addConfiguration(const StreamConfiguration &cfg)
{
config_.push_back(cfg);
}
/**
* \fn CameraConfiguration::validate()
* \brief Validate and possibly adjust the camera configuration
*
* This function adjusts the camera configuration to the closest valid
* configuration and returns the validation status.
*
* \todo Define exactly when to return each status code. Should stream
* parameters set to 0 by the caller be adjusted without returning Adjusted ?
* This would potentially be useful for applications but would get in the way
* in Camera::configure(). Do we need an extra status code to signal this ?
*
* \todo Handle validation of buffers count when refactoring the buffers API.
*
* \return A CameraConfiguration::Status value that describes the validation
* status.
* \retval CameraConfiguration::Invalid The configuration is invalid and can't
* be adjusted. This may only occur in extreme cases such as when the
* configuration is empty.
* \retval CameraConfigutation::Adjusted The configuration has been adjusted
* and is now valid. Parameters may have changed for any stream, and stream
* configurations may have been removed. The caller shall check the
* configuration carefully.
* \retval CameraConfiguration::Valid The configuration was already valid and
* hasn't been adjusted.
*/
/**
* \brief Retrieve a reference to a stream configuration
* \param[in] index Numerical index
*
* The \a index represents the zero based insertion order of stream
* configuration into the camera configuration with addConfiguration(). Calling
* this function with an invalid index results in undefined behaviour.
*
* \return The stream configuration
*/
StreamConfiguration &CameraConfiguration::at(unsigned int index)
{
return config_[index];
}
/**
* \brief Retrieve a const reference to a stream configuration
* \param[in] index Numerical index
*
* The \a index represents the zero based insertion order of stream
* configuration into the camera configuration with addConfiguration(). Calling
* this function with an invalid index results in undefined behaviour.
*
* \return The stream configuration
*/
const StreamConfiguration &CameraConfiguration::at(unsigned int index) const
{
return config_[index];
}
/**
* \fn StreamConfiguration &CameraConfiguration::operator[](unsigned int)
* \brief Retrieve a reference to a stream configuration
* \param[in] index Numerical index
*
* The \a index represents the zero based insertion order of stream
* configuration into the camera configuration with addConfiguration(). Calling
* this function with an invalid index results in undefined behaviour.
*
* \return The stream configuration
*/
/**
* \fn const StreamConfiguration &CameraConfiguration::operator[](unsigned int) const
* \brief Retrieve a const reference to a stream configuration
* \param[in] index Numerical index
*
* The \a index represents the zero based insertion order of stream
* configuration into the camera configuration with addConfiguration(). Calling
* this function with an invalid index results in undefined behaviour.
*
* \return The stream configuration
*/
/**
* \brief Retrieve an iterator to the first stream configuration in the
* sequence
* \return An iterator to the first stream configuration
*/
CameraConfiguration::iterator CameraConfiguration::begin()
{
return config_.begin();
}
/**
* \brief Retrieve a const iterator to the first element of the stream
* configurations
* \return A const iterator to the first stream configuration
*/
CameraConfiguration::const_iterator CameraConfiguration::begin() const
{
return config_.begin();
}
/**
* \brief Retrieve an iterator pointing to the past-the-end stream
* configuration in the sequence
* \return An iterator to the element following the last stream configuration
*/
CameraConfiguration::iterator CameraConfiguration::end()
{
return config_.end();
}
/**
* \brief Retrieve a const iterator pointing to the past-the-end stream
* configuration in the sequence
* \return A const iterator to the element following the last stream
* configuration
*/
CameraConfiguration::const_iterator CameraConfiguration::end() const
{
return config_.end();
}
/**
* \brief Check if the camera configuration is empty
* \return True if the configuration is empty
*/
bool CameraConfiguration::empty() const
{
return config_.empty();
}
/**
* \brief Retrieve the number of stream configurations
* \return Number of stream configurations
*/
std::size_t CameraConfiguration::size() const
{
return config_.size();
}
namespace {
bool isRaw(const PixelFormat &pixFmt)
{
const PixelFormatInfo &info = PixelFormatInfo::info(pixFmt);
return info.isValid() &&
info.colourEncoding == PixelFormatInfo::ColourEncodingRAW;
}
} /* namespace */
/**
* \enum CameraConfiguration::ColorSpaceFlag
* \brief Specify the behaviour of validateColorSpaces
* \var CameraConfiguration::ColorSpaceFlag::None
* \brief No extra validation of color spaces is required
* \var CameraConfiguration::ColorSpaceFlag::StreamsShareColorSpace
* \brief Non-raw output streams must share the same color space
*/
/**
* \typedef CameraConfiguration::ColorSpaceFlags
* \brief A bitwise combination of ColorSpaceFlag values
*/
/**
* \brief Check the color spaces requested for each stream
* \param[in] flags Flags to control the behaviour of this function
*
* This function performs certain consistency checks on the color spaces of
* the streams and may adjust them so that:
*
* - Any raw streams have the Raw color space
* - If the StreamsShareColorSpace flag is set, all output streams are forced
* to share the same color space (this may be a constraint on some platforms).
*
* It is optional for a pipeline handler to use this function.
*
* \return A CameraConfiguration::Status value that describes the validation
* status.
* \retval CameraConfigutation::Adjusted The configuration has been adjusted
* and is now valid. The color space of some or all of the streams may bave
* benn changed. The caller shall check the color spaces carefully.
* \retval CameraConfiguration::Valid The configuration was already valid and
* hasn't been adjusted.
*/
CameraConfiguration::Status CameraConfiguration::validateColorSpaces(ColorSpaceFlags flags)
{
Status status = Valid;
/*
* Set all raw streams to the Raw color space, and make a note of the largest
* non-raw stream with a defined color space (if there is one).
*/
int index = -1;
for (auto [i, cfg] : utils::enumerate(config_)) {
if (isRaw(cfg.pixelFormat)) {
|