PixelBufferAccessor.h

Go to the documentation of this file.

/*
 * 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_PIXEL_BUFFER_ACCESSOR_H
#define META_OCEAN_MEDIA_AVF_PIXEL_BUFFER_ACCESSOR_H
 
#include "ocean/media/avfoundation/AVFoundation.h"
 
#include "ocean/base/Frame.h"
 
#include <AVFoundation/AVFoundation.h>
 
namespace Ocean
{
 
namespace Media
{
 
namespace AVFoundation
{
 
/**
 * This class allows to access a Core Video's CVPixelBuffer.
 * @ingroup mediaavf
 */
class PixelBufferAccessor
{
    public:
 
        /**
         * Creates an invalid accessor object.
         */
        PixelBufferAccessor() = default;
 
        /**
         * Move constructor.
         * @param pixelBufferAccessor The accessor to be moved
         */
        PixelBufferAccessor(PixelBufferAccessor&& pixelBufferAccessor);
 
        /**
         * Creates a new accessor object based on a given pixel buffer.
         * @param pixelBuffer The pixel buffer to be accessed
         * @param readOnly True, access a read-only buffer; False, to access a writable buffer
         */
        explicit PixelBufferAccessor(CVPixelBufferRef pixelBuffer, const bool readOnly);
 
        /*
         * Creates a new accessor object based on a given pixel buffer.
         * @param pixelBuffer The pixel buffer to be accessed
         * @param readOnly True, access a read-only buffer; False, to access a writable buffer
         * @papram accessYPlaneOnly True, to access the grayscale data only; False, to access the entire image data; if the underlying data does not have a Y plane, this flag is ignored, and the entire image is accessed
         */
        explicit PixelBufferAccessor(CVPixelBufferRef pixelBuffer, const bool readOnly, const bool accessYPlaneOnly);
 
        /**
         * Destructs an accessor object.
         */
        ~PixelBufferAccessor();
 
        /**
         * Returns the read-only frame providing access to the pixel buffer.
         * @return The frame with read-only access, if any
         */
        inline const Frame& frame() const;
 
        /**
         * Returns the writable frame providing access to the pixel buffer.
         * @return The frame with writable access, if any
         */
        inline Frame& frame();
 
        /**
         * Explicitly releases this accessor object.
         * This function is also called in the constructor of this accessor.
         */
        void release();
 
        /**
         * Returns whether this accessor has access to a pixel buffer.
         * @return True, if so
         */
        explicit inline operator bool() const;
 
        /**
         * Move operator
         * @param pixelBufferAccessor The accessor to be moved
         * @return Reference to this object
         */
        PixelBufferAccessor& operator=(PixelBufferAccessor&& pixelBufferAccessor);
 
        /**
         * Translates an Apple platform pixel format type to an Ocean pixel format.
         * @param pixelFormat The pixel format to translate
         * @return The translated pixel format, FORMAT_UNDEFINED if the value could not be translated
         */
        static FrameType::PixelFormat translatePixelFormat(const OSType pixelFormat);
 
        /**
         * Translates an Ocean pixel format to an Apple platform pixel format type.
         * @param pixelFormat The pixel format to translate
         * @return The translated pixel format type, 0 if the value could not be translated
         */
        static OSType translatePixelFormat(const FrameType::PixelFormat pixelFormat);
 
    protected:
 
        /**
         * Disabled copy constructor.
         * @param pixelBufferAccessor The accessor which would be copied
         */
        PixelBufferAccessor(const PixelBufferAccessor& pixelBufferAccessor) = delete;
 
        /**
         * Disabled assign operator.
         * @param pixelBufferAccessor The accessor which would be assigned
         * @return Reference to this object
         */
        PixelBufferAccessor& operator=(const PixelBufferAccessor& pixelBufferAccessor) = delete;
 
    protected:
 
        /// The pixel buffer to be accessed.
        CVPixelBufferRef pixelBuffer_ = nullptr;
 
        /// The lock flags.
        CVPixelBufferLockFlags lockFlags_ = 0;
 
        /// The padding frame wrapping the pixel buffer.
        Frame frame_;
 
#ifdef OCEAN_DEBUG
 
        /// Pointer to the frame's memory.
        const void* debugFrameData_ = nullptr;
 
#endif
};
 
inline const Frame& PixelBufferAccessor::frame() const
{
    return frame_;
}
 
inline Frame& PixelBufferAccessor::frame()
{
    return frame_;
}
 
inline PixelBufferAccessor::operator bool() const
{
    return frame_.isValid();
}
 
}
 
}
 
}
 
#endif // META_OCEAN_MEDIA_AVF_PIXEL_BUFFER_ACCESSOR_H