AVFLiveVideo.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_MEDIA_AVF_LIVE_VIDEO_H
#define META_OCEAN_MEDIA_AVF_LIVE_VIDEO_H
 
#include "ocean/media/avfoundation/AVFoundation.h"
#include "ocean/media/avfoundation/AVFFrameMedium.h"
 
#include "ocean/media/LiveVideo.h"
 
namespace Ocean
{
 
namespace Media
{
 
namespace AVFoundation
{
 
/**
 * This class implements a AVFoundation live video object.
 * @ingroup mediaavf
 */
class AVFLiveVideo :
    virtual public AVFFrameMedium,
    virtual public LiveVideo
{
    friend class AVFLibrary;
 
    public:
 
        /**
         * Definition of a callback function for new samples.
         */
        typedef Callback<void, CVPixelBufferRef, SharedAnyCamera, double, double> OnNewSampleCallback;
 
    public:
 
        /**
         * Clones this live video medium and returns a new independent instance of this medium.
         * @see Medium::clone()
         */
        MediumRef clone() const override;
 
        /**
         * Returns the transformation between the camera and device.
         * @see FrameMedium::device_T_camera().
         */
        HomogenousMatrixD4 device_T_camera() const override;
 
        /**
         * Returns the current exposure duration of this device.
         * @see exposureDuration().
         */
        double exposureDuration(double* minDuration = nullptr, double* maxDuration = nullptr, ControlMode* exposureMode = nullptr) const override;
 
        /**
         * Returns the current ISO of this device.
         * @see iso().
         */
        float iso(float* minISO = nullptr, float* maxISO = nullptr, ControlMode* isoMode = nullptr) const override;
 
        /**
         * Returns the current focus of this device.
         * @see focus().
         */
        float focus(ControlMode* focusMode = nullptr) const override;
 
        /**
         * Sets the exposure duriation of this device.
         * @see setExposureDuration().
         */
        bool setExposureDuration(const double duration) override;
 
        /**
         * Sets the ISO of this device.
         * @see setISO().
         */
        bool setISO(const float iso) override;
 
        /**
         * Sets the focus of this device.
         * @see setFocus().
         */
        bool setFocus(const float position) override;
 
        /**
         * Explicitly feeds a new external pixel buffer into this live video.
         * This function is intended for situations in which this live video does not receive the pixel buffers anymore from the system (e.g., when ARKit is accessing the video stream).<br>
         * Do not call this function in case the live video is still receiving pixel buffers from the AVFoundation system.
         * @param pixelBuffer A pointer to a buffer that contains the pixel data of the sample
         * @param anyCamera The profile of the camera, invalid if unknown
         * @param unixTimestamp Used to set timestamp of the Frame associated to the sample (measured in seconds since 1970-01-01 00:00 UTC)
         * @param sampleTime The presentation time of the sample in seconds, used to set the relative timestamp of the frame associated to the sample
         */
        void feedNewSample(CVPixelBufferRef pixelBuffer, SharedAnyCamera anyCamera, const double unixTimestamp, const double sampleTime);
 
    protected:
 
        /**
         * Creates a new live video by a given url.
         * @param url Url of the live video
         */
        explicit AVFLiveVideo(const std::string& url);
 
        /**
         * Destructs a AVFLiveVideo object.
         */
        ~AVFLiveVideo() override;
 
        /**
         * Creates the capture device necessary for the live video.
         * @return True, if succeeded
         */
        bool createCaptureDevice();
 
        /**
         * Creates the capture session neccessary for the live video.
         * This function needs a valid capture device object.
         * @return True, if succeeded
         */
        bool createCaptureSession();
 
        /**
         * Releases the capture session.
         */
        void releaseCaptureSession();
 
        /**
         * Internally starts the medium.
         * @see AVFMedium::internalStart()
         */
        bool internalStart() override;
 
        /**
         * Internally pauses the medium.
         * @see AVFMedium::internalPause()
         */
        bool internalPause() override;
 
        /**
         * Internally stops the medium.
         * @see AVFMedium::internalStop()
         */
        bool internalStop() override;
 
        /**
         * Called, if a new sample arrived.
         * @see AVFFrameMedium::onNewSample(pixelBuffer, unixTimestamp, sampleTime)
         */
        void onNewSample(CVPixelBufferRef pixelBuffer, SharedAnyCamera anyCamera, const double unixTimestamp, const double sampleTime) override;
 
        /**
         * Determines the exact session preset for a specified frame dimension.
         * @param width The width of the frame in pixel, with range (0, infinity)
         * @param height The height of the frame in pixel, with range (0, infinity)
         * @param presetWidth The width of the frame matching to the resulting preset, with range (0, infinity), 0 if no valid preset exists
         * @param presetHeight The height of the frame matching to the resulting preset, with range (0, infinity), 0 if no valid preset exists
         * @return The preset matching to the specified frame dimension, nullptr if no exact preset exists
         */
        static NSString* determineExactPreset(const unsigned int width, const unsigned int height, unsigned int& presetWidth, unsigned int& presetHeight);
 
        /**
         * Determines the best matching or next larger preset for a specified frame dimension.
         * @param width The width of the frame in pixel, with range (0, infinity)
         * @param height The height of the frame in pixel, with range (0, infinity)
         * @param presetWidth The width of the frame matching to the resulting preset, with range (0, infinity)
         * @param presetHeight The height of the frame matching to the resulting preset, with range (0, infinity)
         * @return The best preset better or equal to the specified frame dimension
         */
        static NSString* determineNextLargerPreset(const unsigned int width, const unsigned int height, unsigned int& presetWidth, unsigned int& presetHeight);
 
        /**
         * Returns the best matching (horizontal) field of view for a specified frame dimension.
         * The field of view value is determine from the device's parameters/description, if available.<br>
         * This function is not supported on non-IOS platforms.
         * @param device The device for which the field of view will be determined, must be valid
         * @param width The width of the frame in pixel, with range (0, infinity)
         * @param height The height of the frame in pixel, with range (0, infinity)
         * @return The best matching horizontal field of view in radian, -1 if no field of view could be determined
         */
        static double bestMatchingFieldOfView(AVCaptureDevice* device, const unsigned int width, const unsigned int height);
 
    protected:
 
        /// The capture device object.
        AVCaptureDevice* captureDevice_ = nullptr;
 
        /// The capture session.
        AVCaptureSession* captureSession_ = nullptr;
 
        /// The device input for the capture session.
        AVCaptureDeviceInput* captureDeviceInput_ = nullptr;
 
        /// The video data output for the capture session.
        AVCaptureVideoDataOutput* captureVideoDataOutput_ = nullptr;
 
        /// The delegate object for new sample callbacks.
        NSObject<AVCaptureVideoDataOutputSampleBufferDelegate>* sampleBufferDelegate_ = nullptr;
 
        /// The number of measurements of ISO and exposure values.
        unsigned int isoExposureMeasurements_ = 0u;
 
        /// The sum of ISO values.
        float isoSum_ = 0.0f;
 
        /// The sum of exposure duration values, in seconds.
        float exposureDurationSum_ = 0.0f;
 
        /// The approximated camera profile of this live video.
        SharedAnyCamera approximatedAnyCamera_;
 
        /// The transformation between camera and device.
        HomogenousMatrixD4 device_T_camera_ = HomogenousMatrixD4(true);
};
 
}
 
}
 
}
 
#endif // META_OCEAN_MEDIA_AVF_LIVE_VIDEO_H