/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H
#define HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H
/*
* Contains declaration of an abstract class EmulatedCameraDevice that defines
* functionality expected from an emulated physical camera device:
* - Obtaining and setting camera device parameters
* - Capturing frames
* - Streaming video
* - etc.
*/
#include <utils/threads.h>
#include <utils/KeyedVector.h>
#include <utils/String8.h>
#include "EmulatedCameraCommon.h"
#include "Converters.h"
#include "WorkerThread.h"
#undef min
#undef max
#include <vector>
namespace android {
class EmulatedCamera;
/* Encapsulates an abstract class EmulatedCameraDevice that defines
* functionality expected from an emulated physical camera device:
* - Obtaining and setting camera device parameters
* - Capturing frames
* - Streaming video
* - etc.
*/
class EmulatedCameraDevice {
public:
/* Constructs EmulatedCameraDevice instance.
* Param:
* camera_hal - Emulated camera that implements the camera HAL API, and
* manages (contains) this object.
*/
explicit EmulatedCameraDevice(EmulatedCamera* camera_hal);
/* Destructs EmulatedCameraDevice instance. */
virtual ~EmulatedCameraDevice();
/***************************************************************************
* Emulated camera device abstract interface
**************************************************************************/
public:
/* Connects to the camera device.
* This method must be called on an initialized instance of this class.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t connectDevice() = 0;
/* Disconnects from the camera device.
* Return:
* NO_ERROR on success, or an appropriate error status. If this method is
* called for already disconnected, or uninitialized instance of this class,
* a successful status must be returned from this method. If this method is
* called for an instance that is in the "started" state, this method must
* return a failure.
*/
virtual status_t disconnectDevice() = 0;
/* Starts the camera device.
* This method tells the camera device to start capturing frames of the given
* dimensions for the given pixel format. Note that this method doesn't start
* the delivery of the captured frames to the emulated camera. Call
* startDeliveringFrames method to start delivering frames. This method must
* be called on a connected instance of this class. If it is called on a
* disconnected instance, this method must return a failure.
* Param:
* width, height - Frame dimensions to use when capturing video frames.
* pix_fmt - Pixel format to use when capturing video frames.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t startDevice(int width, int height, uint32_t pix_fmt) = 0;
/* Stops the camera device.
* This method tells the camera device to stop capturing frames. Note that
* this method doesn't stop delivering frames to the emulated camera. Always
* call stopDeliveringFrames prior to calling this method.
* Return:
* NO_ERROR on success, or an appropriate error status. If this method is
* called for an object that is not capturing frames, or is disconnected,
* or is uninitialized, a successful status must be returned from this
* method.
*/
virtual status_t stopDevice() = 0;
/***************************************************************************
* Emulated camera device public API
**************************************************************************/
public:
/* Initializes EmulatedCameraDevice instance.
* Derived classes should override this method in order to cache static
* properties of the physical device (list of supported pixel formats, frame
* sizes, etc.) If this method is called on an already initialized instance,
* it must return a successful status.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t Initialize();
/* Initializes the white balance modes parameters.
* The parameters are passed by each individual derived camera API to
* represent that different camera manufacturers may have different
* preferences on the white balance parameters. Green channel in the RGB
* color space is fixed to keep the luminance to be reasonably constant.
*
* Param:
* mode the text describing the current white balance mode
* r_scale the scale factor for the R channel in RGB space
* b_scale the scale factor for the B channel in RGB space.
*/
void initializeWhiteBalanceModes(const char* mode,
const float r_scale,
const float b_scale);
/* Starts delivering frames captured from the camera device.
* This method will start the worker thread that would be pulling frames from
* the camera device, and will deliver the pulled frames back to the emulated
* camera via onNextFrameAvailable callback. This method must be called on a
* connected instance of this class with a started camera device. If it is
* called on a disconnected instance, or camera device has not been started,
* this method must return a failure.
* Param:
* one_burst - Controls how many frames should be delivered. If this
* parameter is 'true', only one captured frame will be delivered to the
* emulated camera. If this parameter is 'false', frames will keep
* coming until stopDeliveringFrames method is called. Typically, this
* parameter is set to 'true' only in order to obtain a single frame
* that will be used as a "picture" in takePicture method of the
* emulated camera.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t startDeliveringFrames(bool one_burst);
/* Stops delivering frames captured from the camera device.
* This method will stop the worker thread started by startDeliveringFrames.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t stopDeliveringFrames();
/* Set the preview frame rate.
* Indicates the rate at which the camera should provide preview frames in
* frames per second. */
status_t setPreviewFrameRate(int framesPerSecond);
/* Sets the exposure compensation for the camera device.
*/
void setExposureCompensation(const float ev);
/* Sets the white balance mode for the device.
*/
void setWhiteBalanceMode(const char* mode);
/* Gets current framebuffer in a selected format
* This method must be called on a connected instance of this class with a
* started camera device. If it is called on a disconnected instance, or
* camera device has not been started, this method must return a failure.
* Note that this method should be called only after at least one frame has
* been captured and delivered. Otherwise it will return garbage in the
* preview frame buffer. Typically, this method should be called from
* onNextFrameAvailable callback. The method can perform some basic pixel
* format conversion for the most efficient conversions. If a conversion
* is not supported the method will fail. Note that this does NOT require
* that the current frame be locked using a FrameLock object.
*
* Param:
* buffer - Buffer, large enough to contain the entire frame.
* pixelFormat - The pixel format to convert to, use
* getOriginalPixelFormat() to get the configured pixel
* format (if using this no conversion will be needed)
* timestamp - Receives the timestamp at which the preview frame was
* generated.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t getCurrentFrame(void* buffer, uint32_t pixelFormat,
int64_t* timestamp);
/* Gets current framebuffer, converted into preview frame format.
* This method must be called on a connected instance of this class with a
* started camera device. If it is called on a disconnected instance, or
* camera device has not been started, this method must return a failure.
* Note that this method should be called only after at least one frame has
* been captured and delivered. Otherwise it will return garbage in the
* preview frame buffer. Typically, this method should be called from
* onNextFrameAvailable callback. Note that this does NOT require that the
* current frame be locked using a FrameLock object.
* Param:
* buffer - Buffer, large enough to contain the entire preview frame.
* timestamp - Receives the timestamp at which the preview frame was
* generated.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t getCurrentPreviewFrame(void* buffer, int64_t* timestamp);
/* Gets a pointer to the current frame buffer in its raw format.
* This method must be called on a connected instance of this class with a
* started camera device. If it is called on a disconnected instance, or
* camera device has not been started, this method must return NULL.
* This method should only be called when the frame lock is held through
* a FrameLock object. Otherwise the contents of the frame might change
* unexpectedly or its memory could be deallocated leading to a crash.
* Return:
* A pointer to the current frame buffer on success, NULL otherwise.
*/
virtual const void* getCurrentFrame();
class FrameLock {
public:
FrameLock(EmulatedCameraDevice& cameraDevice);
~FrameLock();
private:
EmulatedCameraDevice& mCameraDevice;
};
/* Gets width of the frame obtained from the physical device.
* Return:
* Width of the frame obtained from the physical device. Note that value
* returned from this method is valid only in case if camera device has been
* started.
*/
inline int getFrameWidth() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
return mFrameWidth;
}
/* Gets height of the frame obtained from the physical device.
* Return:
* Height of the frame obtained from the physical device. Note that value
* returned from this method is valid only in case if camera device has been
* started.
*/
inline int getFrameHeight() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
return mFrameHeight;
}
/* Gets byte size of the current frame buffer.
* Return:
* Byte size of the frame buffer. Note that value returned from this method
* is valid only in case if camera device has been started.
*/
inline size_t getFrameBufferSize() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
return mFrameBufferSize;
}
/* Get number of bytes required to store current video frame buffer. Note
* that this can be different from getFrameBufferSize depending on the pixel
* format and resolution. The video frames use a pixel format that is
* suitable for the encoding pipeline and this may have different alignment
* requirements than the pixel format used for regular frames.
*/
inline size_t getVideoFrameBufferSize() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
// Currently the video format is always YUV 420 without any kind of
// alignment. So each pixel uses 12 bits, and then we divide by 8 to get
// the size in bytes. If additional pixel formats are supported this
// should be updated to take the selected video format into
// consideration.
return (mFrameWidth * mFrameHeight * 12) / 8;
}
/* Gets number of pixels in the current frame buffer.
* Return:
* Number of pixels in the frame buffer. Note that value returned from this
* method is valid only in case if camera device has been started.
*/
inline int getPixelNum() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
return mTotalPixels;
}
/* Gets pixel format of the frame that camera device streams to this class.
* Throughout camera framework, there are three different forms of pixel
* format representation:
* - Original format, as reported by the actual camera device. Values for
* this format are declared in bionic/libc/kernel/common/linux/videodev2.h
* - String representation as defined in CameraParameters::PIXEL_FORMAT_XXX
* strings in frameworks/base/include/camera/CameraParameters.h
* - HAL_PIXEL_FORMAT_XXX format, as defined in system/core/include/system/graphics.h
* Since emulated camera device gets its data from the actual device, it gets
* pixel format in the original form. And that's the pixel format
* representation that will be returned from this method. HAL components will
* need to translate value returned from this method to the appropriate form.
* This method must be called only on started instance of this class, since
* it's applicable only when camera device is ready to stream frames.
* Param:
* pix_fmt - Upon success contains the original pixel format.
* Return:
* Current framebuffer's pixel format. Note that value returned from this
* method is valid only in case if camera device has been started.
*/
inline uint32_t getOriginalPixelFormat() const
{
ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
return mPixelFormat;
}
/*
* State checkers.
*/
inline bool isInitialized() const {
return mState != ECDS_CONSTRUCTED;
}
inline bool isConnected() const {
/* Instance is connected when its status is either"connected", or
* "started". */
return mState == ECDS_CONNECTED || mState == ECDS_STARTED;
}
inline bool isStarted() const {
return mState == ECDS_STARTED;
}
/* Enable auto-focus for the camera, this is only possible between calls to
* startPreview and stopPreview, i.e. when preview frames are being
* delivered. This will eventually trigger a callback to the camera HAL
* saying auto-focus completed.
*/
virtual status_t setAutoFocus();
/* Cancel auto-focus if it's enabled.
*/
virtual status_t cancelAutoFocus();
/* Request an asynchronous camera restart with new image parameters. The
* restart will be performed on the same thread that delivers frames,
* ensuring that all callbacks are done from the same thread.
* Return
* false if the thread request cannot be honored because no thread is
* running or some other error occured.
*/
bool requestRestart(int width, int height, uint32_t pixelFormat,
bool takingPicture, bool oneBurst);
/****************************************************************************
* Emulated camera device private API
***************************************************************************/
protected:
/* Performs common validation and calculation of startDevice parameters.
* Param:
* width, height, pix_fmt - Parameters passed to the startDevice method.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t commonStartDevice(int width, int height, uint32_t pix_fmt);
/* Performs common cleanup on stopDevice.
* This method will undo what commonStartDevice had done.
*/
virtual void commonStopDevice();
/** Computes a luminance value after taking the exposure compensation.
* value into account.
*
* Param:
* inputY - The input luminance value.
* Return:
* The luminance value after adjusting the exposure compensation.
*/
inline uint8_t changeExposure(const uint8_t& inputY) const {
return static_cast<uint8_t>(clamp(static_cast<float>(inputY) *
mExposureCompensation));
}
/** Computes the pixel value in YUV space after adjusting to the current
* white balance mode.
*/
void changeWhiteBalance(uint8_t& y, uint8_t& u, uint8_t& v) const;
/* Check if there is a pending auto-focus trigger and send a notification
* if there is. This should be called from the worker thread loop if the
* camera device wishes to use the default behavior of immediately sending
* an auto-focus completion event on request. Otherwise the device should
* implement its own auto-focus behavior. */
void checkAutoFocusTrigger();
/* Implementation for getCurrentFrame that includes pixel format conversion
* if needed. This allows subclasses to easily use this method instead of
* having to reimplement the conversion all over.
*/
status_t getCurrentFrameImpl(const uint8_t* source, uint8_t* dest,
uint32_t pixelFormat) const;
/****************************************************************************
* Worker thread management.
* Typicaly when emulated camera device starts capturing frames from the
* actual device, it does that in a worker thread created in StartCapturing,
* and terminated in StopCapturing. Since this is such a typical scenario,
* it makes sence to encapsulate worker thread management in the base class
* for all emulated camera devices.
***************************************************************************/
protected:
/* Starts the worker thread.
* Typically, the worker thread is started from the startDeliveringFrames
* method of this class.
* Param:
* one_burst - Controls how many times thread loop should run. If this
* parameter is 'true', thread routine will run only once If this
* parameter is 'false', thread routine will run until
* stopWorkerThreads method is called. See startDeliveringFrames for
* more info.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t startWorkerThread(bool one_burst);
/* Stop the worker thread.
* Note that this method will always wait for the worker thread to
* terminate. Typically, the worker thread is stopped from the
* stopDeliveringFrames method of this class.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t stopWorkerThread();
/* Produce a camera frame and place it in buffer. The buffer is one of
* the two buffers provided to mFrameProducer during construction along with
* a pointer to this method. The method is expected to know what size frames
* it provided to the producer thread. Returning false indicates an
* unrecoverable error that will stop the frame production thread. */
virtual bool produceFrame(void* buffer, int64_t* timestamp) = 0;
/* Get the primary buffer to use when constructing the FrameProducer. */
virtual void* getPrimaryBuffer() {
return mFrameBuffers[0].data();
}
/* Get the seconary buffer to use when constructing the FrameProducer. */
virtual void* getSecondaryBuffer() {
return mFrameBuffers[1].data();
}
/* A class that encaspulates the asynchronous behavior of a camera. This
* includes asynchronous production (through another thread), frame delivery
* as well as asynchronous state changes that have to be synchronized with
* frame production and delivery but can't be blocking the camera HAL. */
class CameraThread : public WorkerThread {
public:
typedef bool (*ProduceFrameFunc)(void* opaque,
void* destinationBuffer,
int64_t* destinationTimestamp);
CameraThread(EmulatedCameraDevice* cameraDevice,
ProduceFrameFunc producer,
void* producerOpaque);
/* Access the primary buffer of the frame producer, this is the frame
* that is currently not being written to. The buffer will only have
* valid contents if hasFrame() returns true. Note that accessing this
* without first having created a Lock can lead to contents changing
* without notice. */
const void* getPrimaryBuffer() const;
int64_t getPrimaryTimestamp() const;
/* Lock and unlock the primary buffer */
void lockPrimaryBuffer();
void unlockPrimaryBuffer();
void requestRestart(int width, int height, uint32_t pixelFormat,
bool takingPicture, bool oneBurst);
private:
bool checkRestartRequest();
bool waitForFrameOrTimeout(nsecs_t timeout);
bool inWorkerThread() override;
status_t onThreadStart() override;
void onThreadExit() override;
/* A class with a thread that will call a function at a specified
* interval to produce frames. This is done in a double-buffered fashion
* to make sure that one of the frames can be delivered without risk of
* overwriting its contents. Access to the primary buffer, the one NOT
* being drawn to, should be protected with the lock methods provided or
* the guarantee of not overwriting the contents does not hold.
*/
class FrameProducer : public WorkerThread {
public:
FrameProducer(EmulatedCameraDevice* cameraDevice,
ProduceFrameFunc producer, void* opaque,
void* primaryBuffer, void* secondaryBuffer);
/* Indicates if the producer has produced at least one frame. */
bool hasFrame() const;
const void* getPrimaryBuffer() const;
int64_t getPrimaryTimestamp() const;
void lockPrimaryBuffer();
void unlockPrimaryBuffer();
protected:
bool inWorkerThread() override;
ProduceFrameFunc mProducer;
void* mOpaque;
void* mPrimaryBuffer;
void* mSecondaryBuffer;
int64_t mPrimaryTimestamp;
int64_t mSecondaryTimestamp;
nsecs_t mLastFrame;
mutable Mutex mBufferMutex;
std::atomic<bool> mHasFrame;
};
nsecs_t mCurFrameTimestamp;
/* Worker thread that will produce frames for the camera thread */
sp<FrameProducer> mFrameProducer;
ProduceFrameFunc mProducerFunc;
void* mProducerOpaque;
Mutex mRequestMutex;
int mRestartWidth;
int mRestartHeight;
uint32_t mRestartPixelFormat;
bool mRestartOneBurst;
bool mRestartTakingPicture;
bool mRestartRequested;
};
/****************************************************************************
* Data members
***************************************************************************/
protected:
/* Locks this instance for parameters, state, etc. change. */
Mutex mObjectLock;
/* A camera thread that is used in frame production, delivery and handling
* of asynchronous restarts. Internally the process of generating and
* delivering frames is split up into two threads. This way frames can
* always be delivered on time even if they cannot be produced fast enough
* to keep up with the expected frame rate. It also increases performance on
* multi-core systems. If the producer cannot keep up the last frame will
* simply be delivered again. */
sp<CameraThread> mCameraThread;
/* Emulated camera object containing this instance. */
EmulatedCamera* mCameraHAL;
/* Framebuffers containing the frame being drawn to and the frame being
* delivered. This is used by the double buffering producer thread and
* the consumer thread will copy frames from one of these buffers to
* mCurrentFrame to avoid being stalled by frame production. */
std::vector<uint8_t> mFrameBuffers[2];
/*
* Framebuffer properties.
*/
/* Byte size of the framebuffer. */
size_t mFrameBufferSize;
/* Original pixel format (one of the V4L2_PIX_FMT_XXX values, as defined in
* bionic/libc/kernel/common/linux/videodev2.h */
uint32_t mPixelFormat;
/* Frame width */
int mFrameWidth;
/* Frame height */
int mFrameHeight;
/* The number of frames per second that the camera should deliver */
int mFramesPerSecond;
/* Defines byte distance between the start of each Y row */
int mYStride;
/* Defines byte distance between the start of each U/V row. For formats with
* separate U and V planes this is the distance between rows in each plane.
* For formats with interleaved U and V components this is the distance
* between rows in the interleaved plane, meaning that it's the stride over
* the combined U and V components. */
int mUVStride;
/* Total number of pixels */
int mTotalPixels;
/* Exposure compensation value */
float mExposureCompensation;
float* mWhiteBalanceScale;
DefaultKeyedVector<String8, float*> mSupportedWhiteBalanceScale;
/* Defines possible states of the emulated camera device object.
*/
enum EmulatedCameraDeviceState {
/* Object has been constructed. */
ECDS_CONSTRUCTED,
/* Object has been initialized. */
ECDS_INITIALIZED,
/* Object has been connected to the physical device. */
ECDS_CONNECTED,
/* Camera device has been started. */
ECDS_STARTED,
};
/* Object state. */
EmulatedCameraDeviceState mState;
private:
/* Lock the current frame so that it can safely be accessed using
* getCurrentFrame. Prefer using a FrameLock object on the stack instead
* to ensure that the lock is always unlocked properly.
*/
void lockCurrentFrame();
/* Unlock the current frame after locking it. Prefer using a FrameLock
* object instead.
*/
void unlockCurrentFrame();
static bool staticProduceFrame(void* opaque, void* buffer,
int64_t* timestamp) {
auto cameraDevice = reinterpret_cast<EmulatedCameraDevice*>(opaque);
return cameraDevice->produceFrame(buffer, timestamp);
}
/* A flag indicating if an auto-focus completion event should be sent the
* next time the worker thread runs. This implies that auto-focus completion
* event can only be delivered while preview frames are being delivered.
* This is also a requirement specified in the documentation where a request
* to perform auto-focusing is only valid between calls to startPreview and
* stopPreview.
* https://developer.android.com/reference/android/hardware/Camera.html#autoFocus(android.hardware.Camera.AutoFocusCallback)
*/
std::atomic<bool> mTriggerAutoFocus;
};
}; /* namespace android */
#endif /* HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H */