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#ifndef OPENCV_CUDACODEC_HPP
#define OPENCV_CUDACODEC_HPP

#ifndef __cplusplus
#  error cudacodec.hpp header must be compiled as C++
#endif

#include "opencv2/core/cuda.hpp"

/**
  @addtogroup cuda
  @{
    @defgroup cudacodec Video Encoding/Decoding
  @}
 */

namespace cv { namespace cudacodec {

//! @addtogroup cudacodec
//! @{

////////////////////////////////// Video Encoding //////////////////////////////////

/** @brief Video codecs supported by cudacodec::VideoReader and cudacodec::VideoWriter.
@note
   -   Support will depend on your hardware, refer to the Nvidia Video Codec SDK Video Encode and Decode GPU Support Matrix for details.
 */
enum Codec
{
    MPEG1 = 0,
    MPEG2,
    MPEG4,
    VC1,
    H264,
    JPEG,
    H264_SVC,
    H264_MVC,
    HEVC,
    VP8,
    VP9,
    AV1,
    NumCodecs,

    Uncompressed_YUV420 = (('I' << 24) | ('Y' << 16) | ('U' << 8) | ('V')),   //!< Y,U,V (4:2:0)
    Uncompressed_YV12 = (('Y' << 24) | ('V' << 16) | ('1' << 8) | ('2')),   //!< Y,V,U (4:2:0)
    Uncompressed_NV12 = (('N' << 24) | ('V' << 16) | ('1' << 8) | ('2')),   //!< Y,UV  (4:2:0)
    Uncompressed_YUYV = (('Y' << 24) | ('U' << 16) | ('Y' << 8) | ('V')),   //!< YUYV/YUY2 (4:2:2)
    Uncompressed_UYVY = (('U' << 24) | ('Y' << 16) | ('V' << 8) | ('Y'))    //!< UYVY (4:2:2)
};

/** @brief ColorFormat for the frame returned by VideoReader::nextFrame() and VideoReader::retrieve() or used to initialize a VideoWriter.
*/
enum ColorFormat {
    UNDEFINED = 0,
    BGRA = 1, //!< OpenCV color format. VideoReader and VideoWriter.
    BGR = 2, //!< OpenCV color format. VideoReader and VideoWriter.
    GRAY = 3, //!< OpenCV color format. VideoReader and VideoWriter.
    RGB = 5, //!< OpenCV color format. VideoReader and VideoWriter.
    RGBA = 6, //!< OpenCV color format. VideoReader and VideoWriter.
    NV_YUV_SURFACE_FORMAT = 7, //!< Nvidia YUV Surface Format output by the Nvidia decoder, see @ref SurfaceFormat. VideoReader only.
    NV_NV12 = 4, //!< Nvidia Buffer Format - Semi-Planar YUV [Y plane followed by interleaved UV plane]. VideoWriter only. @deprecated Deprecated for use with VideoReader, use @ref NV_YUV_SURFACE_FORMAT instead.
    NV_YV12 = 8, //!< Nvidia Buffer Format - Planar YUV [Y plane followed by V and U planes]. VideoWriter only.
    NV_IYUV = 9, //!< Nvidia Buffer Format - Planar YUV [Y plane followed by U and V planes]. VideoWriter only.
    NV_YUV444 = 10, //!< Nvidia Buffer Format - Planar YUV [Y plane followed by U and V planes]. VideoWriter only.
    NV_AYUV = 11, //!< Nvidia Buffer Format - 8 bit Packed A8Y8U8V8. This is a word-ordered format where a pixel is represented by a 32-bit word with V in the lowest 8 bits, U in the next 8 bits, Y in the 8 bits after that and A in the highest 8 bits. VideoWriter only.
    NV_YUV420_10BIT = 12, //!< Nvidia Buffer Format - 10 bit Semi-Planar YUV [Y plane followed by interleaved UV plane]. Each pixel of size 2 bytes. Most Significant 10 bits contain pixel data. VideoWriter only.
    NV_YUV444_10BIT = 13, //!< Nvidia Buffer Format - 10 bit Planar YUV444 [Y plane followed by U and V planes]. Each pixel of size 2 bytes. Most Significant 10 bits contain pixel data. VideoWriter only.
#ifndef CV_DOXYGEN
    PROP_NOT_SUPPORTED
#endif
};

/** @brief Rate Control Modes.
*/
enum EncodeParamsRcMode {
    ENC_PARAMS_RC_CONSTQP = 0x0, //!< Constant QP mode.
    ENC_PARAMS_RC_VBR = 0x1, //!< Variable bitrate mode.
    ENC_PARAMS_RC_CBR = 0x2 //!< Constant bitrate mode.
};

/** @brief Multi Pass Encoding.
*/
enum EncodeMultiPass
{
    ENC_MULTI_PASS_DISABLED = 0x0, //!< Single Pass.
    ENC_TWO_PASS_QUARTER_RESOLUTION = 0x1, //!< Two Pass encoding is enabled where first Pass is quarter resolution.
    ENC_TWO_PASS_FULL_RESOLUTION = 0x2, //!< Two Pass encoding is enabled where first Pass is full resolution.
};


/** @brief Supported Encoder Profiles.
*/
enum EncodeProfile {
    ENC_CODEC_PROFILE_AUTOSELECT = 0,
    ENC_H264_PROFILE_BASELINE = 1,
    ENC_H264_PROFILE_MAIN = 2,
    ENC_H264_PROFILE_HIGH = 3,
    ENC_H264_PROFILE_HIGH_444 = 4,
    ENC_H264_PROFILE_STEREO = 5,
    ENC_H264_PROFILE_PROGRESSIVE_HIGH = 6,
    ENC_H264_PROFILE_CONSTRAINED_HIGH = 7,
    ENC_HEVC_PROFILE_MAIN = 8,
    ENC_HEVC_PROFILE_MAIN10 = 9,
    ENC_HEVC_PROFILE_FREXT = 10
};

/** @brief Nvidia Encoding Presets. Performance degrades and quality improves as we move from P1 to P7.
*/
enum EncodePreset {
    ENC_PRESET_P1 = 1,
    ENC_PRESET_P2 = 2,
    ENC_PRESET_P3 = 3,
    ENC_PRESET_P4 = 4,
    ENC_PRESET_P5 = 5,
    ENC_PRESET_P6 = 6,
    ENC_PRESET_P7 = 7
};

/** @brief Tuning information.
*/
enum EncodeTuningInfo {
    ENC_TUNING_INFO_UNDEFINED = 0, //!< Undefined tuningInfo. Invalid value for encoding.
    ENC_TUNING_INFO_HIGH_QUALITY = 1, //!< Tune presets for latency tolerant encoding.
    ENC_TUNING_INFO_LOW_LATENCY = 2, //!< Tune presets for low latency streaming.
    ENC_TUNING_INFO_ULTRA_LOW_LATENCY = 3, //!< Tune presets for ultra low latency streaming.
    ENC_TUNING_INFO_LOSSLESS = 4, //!< Tune presets for lossless encoding.
    ENC_TUNING_INFO_COUNT
};

/** Quantization Parameter for each type of frame when using ENC_PARAMS_RC_MODE::ENC_PARAMS_RC_CONSTQP.
*/
struct CV_EXPORTS_W_SIMPLE EncodeQp
{
    CV_PROP_RW uint32_t qpInterP; //!< Specifies QP value for P-frame.
    CV_PROP_RW uint32_t qpInterB; //!< Specifies QP value for B-frame.
    CV_PROP_RW uint32_t qpIntra; //!< Specifies QP value for Intra Frame.
};

/** @brief Different parameters for CUDA video encoder.
*/
struct CV_EXPORTS_W_SIMPLE EncoderParams
{
public:
    CV_WRAP EncoderParams() : nvPreset(ENC_PRESET_P3), tuningInfo(ENC_TUNING_INFO_HIGH_QUALITY), encodingProfile(ENC_CODEC_PROFILE_AUTOSELECT),
        rateControlMode(ENC_PARAMS_RC_VBR), multiPassEncoding(ENC_MULTI_PASS_DISABLED), constQp({ 0,0,0 }), averageBitRate(0), maxBitRate(0),
        targetQuality(30), gopLength(250), idrPeriod(250), videoFullRangeFlag(false){};
    CV_PROP_RW EncodePreset nvPreset;
    CV_PROP_RW EncodeTuningInfo tuningInfo;
    CV_PROP_RW EncodeProfile encodingProfile;
    CV_PROP_RW EncodeParamsRcMode rateControlMode;
    CV_PROP_RW EncodeMultiPass multiPassEncoding;
    CV_PROP_RW EncodeQp constQp; //!< QP's for \ref ENC_PARAMS_RC_CONSTQP.
    CV_PROP_RW int averageBitRate; //!< target bitrate for \ref ENC_PARAMS_RC_VBR and \ref ENC_PARAMS_RC_CBR.
    CV_PROP_RW int maxBitRate; //!< upper bound on bitrate for \ref ENC_PARAMS_RC_VBR and \ref ENC_PARAMS_RC_CONSTQP.
    CV_PROP_RW uint8_t targetQuality; //!< value 0 - 51 where video quality decreases as targetQuality increases, used with \ref ENC_PARAMS_RC_VBR.
    CV_PROP_RW int gopLength; //!< the number of pictures in one GOP, ensuring \ref idrPeriod >= \ref gopLength.
    CV_PROP_RW int idrPeriod; //!< IDR interval, ensuring \ref idrPeriod >= \ref gopLength.
    CV_PROP_RW bool videoFullRangeFlag;//!< Indicates if the black level, luma and chroma of the source are represented using the full or limited range (AKA TV or "analogue" range) of values as defined in Annex E of the ITU-T Specification.
};
CV_EXPORTS bool operator==(const EncoderParams& lhs, const EncoderParams& rhs);

/** @brief Interface for encoder callbacks.

User can implement own multiplexing by implementing this interface.
*/
class CV_EXPORTS_W EncoderCallback {
public:
    /** @brief Callback function to signal that the encoded bitstream for one or more frames is ready.

    @param vPacket The raw bitstream for one or more frames.
    @param pts Presentation timestamps for each frame in vPacket using the FPS time base.  e.g. fps = 25, pts = 3, presentation time = 3/25 seconds.
    */
    virtual void onEncoded(const std::vector<std::vector<uint8_t>>& vPacket, const std::vector<uint64_t>& pts) = 0;

    /** @brief Set the GOP pattern used by the encoder.

     @param frameIntervalP Specify the GOP pattern as follows : \p frameIntervalP = 0: I, 1 : IPP, 2 : IBP, 3 : IBBP.
    */
    virtual bool setFrameIntervalP(const int frameIntervalP) = 0;

    /** @brief Callback function to that the encoding has finished.
    * */
    virtual void onEncodingFinished() = 0;

    virtual ~EncoderCallback() {}
};

/** @brief Video writer interface, see createVideoWriter().

Available if Nvidia's Video Codec SDK is installed.

Only Codec::H264 and Codec::HEVC are supported with encoding support dependent on the GPU, refer to the Nvidia Video Codec SDK Video Encode and Decode GPU Support Matrix for details.

@note
   -   An example on how to use the VideoWriter class can be found at
        opencv_source_code/samples/gpu/video_writer.cpp
*/
class CV_EXPORTS_W VideoWriter
{
public:
    virtual ~VideoWriter() {}

    /** @brief Writes the next video frame.

    @param frame The framet to be written.

    The method encodes the specified image to a video stream. The image must have the same size and the same
    surface format as has been specified when opening the video writer.
    */
    CV_WRAP virtual void write(InputArray frame) = 0;

    /** @brief Retrieve the encoding parameters.
    */
    CV_WRAP virtual EncoderParams getEncoderParams() const = 0;

    /** @brief Waits until the encoding process has finished before calling EncoderCallback::onEncodingFinished().
    */
    CV_WRAP virtual void release() = 0;
};

/** @brief Creates video writer.

@param fileName Name of the output video file.
@param frameSize Size of the input video frames.
@param codec Supports Codec::H264 and Codec::HEVC.
@param fps Framerate of the created video stream.
@param colorFormat OpenCv color format of the frames to be encoded.
@param encoderCallback Callbacks for video encoder. See cudacodec::EncoderCallback. Required for working with the encoded video stream.
@param stream Stream for frame pre-processing.
*/
CV_EXPORTS_W Ptr<cudacodec::VideoWriter> createVideoWriter(const String& fileName, const Size frameSize, const Codec codec = Codec::H264, const double fps = 25.0,
    const ColorFormat colorFormat = ColorFormat::BGR, Ptr<EncoderCallback> encoderCallback = 0, const cuda::Stream& stream = cuda::Stream::Null());

/** @brief Creates video writer.

@param fileName Name of the output video file.
@param frameSize Size of the input video frames.
@param codec Supports Codec::H264 and Codec::HEVC.
@param fps Framerate of the created video stream.
@param colorFormat OpenCv color format of the frames to be encoded.
@param params Additional encoding parameters.
@param encoderCallback Callbacks for video encoder. See cudacodec::EncoderCallback. Required for working with the encoded video stream.
@param stream Stream for frame pre-processing.
*/
CV_EXPORTS_W Ptr<cudacodec::VideoWriter> createVideoWriter(const String& fileName, const Size frameSize, const Codec codec, const double fps,  const ColorFormat colorFormat,
    const EncoderParams& params, Ptr<EncoderCallback> encoderCallback = 0, const cuda::Stream& stream = cuda::Stream::Null());

////////////////////////////////// Video Decoding //////////////////////////////////////////

/** @brief Chroma formats supported by cudacodec::VideoReader.
 */
enum ChromaFormat
{
    Monochrome = 0,
    YUV420,
    YUV422,
    YUV444,
    NumFormats
};

/** @brief Deinterlacing mode used by decoder. */
enum DeinterlaceMode
{
    Weave = 0, //!< Weave both fields(no deinterlacing).For progressive content and for content that doesn't need deinterlacing.
    Bob = 1, //!< Drop one field.
    Adaptive = 2 //!< Adaptive deinterlacing needs more video memory than other deinterlacing modes.
};

/** @brief Video Signal Description Color Primaries of the VideoReader source (section E.2.1 VUI parameters semantics of H265 spec file) */
enum class ColorSpaceStandard {
    BT709 = 1, //!< ITU-R BT.709 standard for high-definition television.
    Unspecified = 2, //!< Unspecified color space standard.
    Reserved = 3, //!< Reserved for future use.
    FCC = 4, //!< FCC color space standard.
    BT470 = 5, //!< ITU - R BT.470, used for older analog television systems.
    BT601 = 6, //!< ITU - R BT.601, used for standard definition television.
    SMPTE240M = 7, //!< SMPTE 240M, used for early HDTV systems.
    YCgCo = 8, //!< YCgCo color space, used in some video compression algorithms.
    BT2020 = 9, //!< ITU - R BT.2020, used for ultra-high-definition television.
    BT2020C = 10 //!< ITU - R BT.2020 Constant Luminance, used for ultra-high-definition television.
};

/** @brief Video surface formats output by the decoder */
enum SurfaceFormat {
    SF_NV12 = 0, //!< Semi-Planar YUV [Y plane followed by interleaved UV plane]
    SF_P016 = 1, //!< 16 bit Semi-Planar YUV [Y plane followed by interleaved UV plane]. Can be used for 10 bit(6LSB bits 0), 12 bit (4LSB bits 0)
    SF_YUV444 = 2, //!< Planar YUV [Y plane followed by U and V planes]
    SF_YUV444_16Bit = 3 //!< 16 bit Planar YUV [Y plane followed by U and V planes]. Can be used for 10 bit(6LSB bits 0), 12 bit (4LSB bits 0)
};

/** @brief Bit depth of the frame returned by VideoReader::nextFrame() and VideoReader::retrieve()  */
enum BitDepth {
    EIGHT = 0, //!< 8 bit depth.
    SIXTEEN = 1, //!< 16 bit depth.
    UNCHANGED = 2 //!< Use source bit depth.
};

/** @brief Utility function demonstrating how to map the luma histogram when FormatInfo::videoFullRangeFlag == false
    @param hist Luma histogram \a hist returned from VideoReader::nextFrame(GpuMat& frame, GpuMat& hist, Stream& stream).
    @param histFull Host histogram equivelent to downloading \a hist after calling cuda::calcHist(InputArray frame, OutputArray hist, Stream& stream).

    @note
    -   This function demonstrates how to map the luma histogram back so that it is equivalent to the result obtained from cuda::calcHist()
    if the returned frame was ColorFormat::GRAY.
 */
CV_EXPORTS_W void MapHist(const cuda::GpuMat& hist, CV_OUT Mat& histFull);

/** @brief Struct providing information about video file format. :
 */
struct CV_EXPORTS_W_SIMPLE FormatInfo
{
    CV_WRAP FormatInfo() : nBitDepthMinus8(-1), ulWidth(0), ulHeight(0), width(0), height(0), ulMaxWidth(0), ulMaxHeight(0), valid(false),
        fps(0), ulNumDecodeSurfaces(0), videoFullRangeFlag(false), colorSpaceStandard(ColorSpaceStandard::BT601), enableHistogram(false), nCounterBitDepth(0), nMaxHistogramBins(0){};

    CV_PROP_RW Codec codec;
    CV_PROP_RW ChromaFormat chromaFormat;
    CV_PROP_RW SurfaceFormat surfaceFormat; //!< Surface format of the decoded frame.
    CV_PROP_RW int nBitDepthMinus8;
    CV_PROP_RW int nBitDepthChromaMinus8;
    CV_PROP_RW int ulWidth;//!< Coded sequence width in pixels.
    CV_PROP_RW int ulHeight;//!< Coded sequence height in pixels.
    CV_PROP_RW int width;//!< Width of the decoded frame returned by nextFrame(frame).
    CV_PROP_RW int height;//!< Height of the decoded frame returned by nextFrame(frame).
    int ulMaxWidth;
    int ulMaxHeight;
    CV_PROP_RW Rect displayArea;//!< ROI inside the decoded frame returned by nextFrame(frame), containing the useable video frame.
    CV_PROP_RW bool valid;
    CV_PROP_RW double fps;
    CV_PROP_RW int ulNumDecodeSurfaces;//!< Maximum number of internal decode surfaces.
    CV_PROP_RW DeinterlaceMode deinterlaceMode;
    CV_PROP_RW cv::Size targetSz;//!< Post-processed size of the output frame.
    CV_PROP_RW cv::Rect srcRoi;//!< Region of interest decoded from video source.
    CV_PROP_RW cv::Rect targetRoi;//!< Region of interest in the output frame containing the decoded frame.
    CV_PROP_RW bool videoFullRangeFlag;//!< Output value indicating if the black level, luma and chroma of the source are represented using the full or limited range (AKA TV or "analogue" range) of values as defined in Annex E of the ITU-T Specification.
    CV_PROP_RW ColorSpaceStandard colorSpaceStandard; //!< Video Signal Description Color Primaries of the VideoReader source (section E.2.1 VUI parameters semantics of H265 spec file)
    CV_PROP_RW bool enableHistogram;//!< Flag requesting histogram output if supported. Exception will be thrown when requested but not supported.
    CV_PROP_RW int nCounterBitDepth;//!< Bit depth of histogram bins if histogram output is requested and supported.
    CV_PROP_RW int nMaxHistogramBins;//!< Max number of histogram bins if histogram output is requested and supported.
};

/** @brief Class for converting the raw YUV Surface output from VideoReader if output color format is set to ColorFormat::NV_YUV_SURFACE_FORMAT (VideoReader::set(ColorFormat::NV_YUV_SURFACE_FORMAT)) to the requested @ref ColorFormat.
 */
class CV_EXPORTS_W NVSurfaceToColorConverter {
public:
    /** @brief Performs the conversion from the raw YUV Surface output from VideoReader to the requested color format. Use this function when you want to convert the raw YUV Surface output from VideoReader to more than one color format or you want both the raw Surface output in addition to a color frame.
     * @param yuv The raw YUV Surface output from VideoReader see @ref SurfaceFormat.
     * @param color The converted frame.
     * @param surfaceFormat The surface format of the input YUV data.
     * @param outputFormat The requested output color format.
     * @param bitDepth The requested bit depth of the output frame.
     * @param planar Request seperate planes for each color plane.
     * @param stream Stream for the asynchronous version.
     */
    CV_WRAP virtual bool convert(InputArray yuv, OutputArray color, const SurfaceFormat surfaceFormat, const ColorFormat outputFormat, const BitDepth bitDepth = BitDepth::UNCHANGED, const bool planar = false, cuda::Stream& stream = cuda::Stream::Null()) = 0;
    virtual ~NVSurfaceToColorConverter() {};
};

/** @brief Creates a NVSurfaceToColorConverter.
* @param colorSpace The requested @ref ColorSpaceStandard for the converter.
* @param videoFullRangeFlag Indicates if the black level, luma and chroma of the source are represented using the full or limited range (AKA TV or "analogue" range) of values as defined in Annex E of the ITU-T Specification.
 */
CV_EXPORTS_W Ptr<NVSurfaceToColorConverter> createNVSurfaceToColorConverter(const ColorSpaceStandard colorSpace, const bool videoFullRangeFlag = false);

/** @brief cv::cudacodec::VideoReader generic properties identifier.
*/
enum class VideoReaderProps {
    PROP_DECODED_FRAME_IDX = 0, //!< Index for retrieving the decoded frame using retrieve().
    PROP_EXTRA_DATA_INDEX = 1, //!< Index for retrieving the extra data associated with a video source using retrieve().
    PROP_RAW_PACKAGES_BASE_INDEX = 2, //!< Base index for retrieving raw encoded data using retrieve().
    PROP_NUMBER_OF_RAW_PACKAGES_SINCE_LAST_GRAB = 3, //!< Number of raw packages recieved since the last call to grab().
    PROP_RAW_MODE = 4, //!< Status of raw mode.
    PROP_LRF_HAS_KEY_FRAME = 5, //!< FFmpeg source only - Indicates whether the Last Raw Frame (LRF), output from VideoReader::retrieve() when VideoReader is initialized in raw mode, contains encoded data for a key frame.
    PROP_COLOR_FORMAT = 6, //!< ColorFormat of the decoded frame.  This can be changed before every call to nextFrame() and retrieve().
    PROP_UDP_SOURCE = 7, //!< Status of VideoReaderInitParams::udpSource initialization.
    PROP_ALLOW_FRAME_DROP = 8, //!< Status of VideoReaderInitParams::allowFrameDrop initialization.
    PROP_BIT_DEPTH = 9, //!< Bit depth of the decoded frame. This can be changed before every call to nextFrame() and retrieve().
    PROP_PLANAR = 10, //!< Planar when true, packed when false. This can be changed before every call to nextFrame() and retrieve().
#ifndef CV_DOXYGEN
    PROP_NOT_SUPPORTED
#endif
};

/** @brief Video reader interface, see createVideoReader().

Available if Nvidia's Video Codec SDK is installed.

Decoding support is dependent on the GPU, refer to the Nvidia Video Codec SDK Video Encode and Decode GPU Support Matrix for details.

@note
   -   An example on how to use the VideoReader interface can be found at
        opencv_source_code/samples/gpu/video_reader.cpp
 */
class CV_EXPORTS_W VideoReader
{
public:
    virtual ~VideoReader() {}

    /** @brief Grabs, decodes and returns the next video frame.

    @param [out] frame The video frame.
    @param stream Stream for the asynchronous version.
    @return `false` if no frames have been grabbed.

    If no frames have been grabbed (there are no more frames in video file), the methods return false.
    The method throws an Exception if error occurs.
     */
    CV_WRAP virtual bool nextFrame(CV_OUT cuda::GpuMat& frame, cuda::Stream &stream = cuda::Stream::Null()) = 0;

    /** @brief Grabs, decodes and returns the next video frame and frame luma histogram.

    @param [out] frame The video frame.
    @param [out] histogram Histogram of the luma component of the encoded frame, see note.
    @param stream Stream for the asynchronous version.
    @return `false` if no frames have been grabbed.

    If no frames have been grabbed (there are no more frames in video file), the methods return false.
    The method throws an Exception if error occurs.

    @note Histogram data is collected by NVDEC during the decoding process resulting in zero performance penalty. NVDEC computes the histogram data for only the luma component of decoded output, not on post-processed frame(i.e. when scaling, cropping, etc. applied).  If the source is encoded using a limited range of luma values (FormatInfo::videoFullRangeFlag == false) then the histogram bin values will correspond to to this limited range of values and will need to be mapped to contain the same output as cuda::calcHist().  The MapHist() utility function can be used to perform this mapping on the host if required.
     */
    CV_WRAP_AS(nextFrameWithHist) virtual bool nextFrame(CV_OUT cuda::GpuMat& frame, CV_OUT cuda::GpuMat& histogram, cuda::Stream& stream = cuda::Stream::Null()) = 0;

    /** @brief Returns information about video file format.
    */
    CV_WRAP virtual FormatInfo format() const = 0;

    /** @brief Grabs the next frame from the video source.

    @param stream Stream for the asynchronous version.
    @return `true` (non-zero) in the case of success.

    The method/function grabs the next frame from video file or camera and returns true (non-zero) in
    the case of success.

    The primary use of the function is for reading both the encoded and decoded video data when rawMode is enabled.  With rawMode enabled
    retrieve() can be called following grab() to retrieve all the data associated with the current video source since the last call to grab() or the creation of the VideoReader.
     */
    CV_WRAP virtual bool grab(cuda::Stream& stream = cuda::Stream::Null()) = 0;

    /** @brief Returns previously grabbed video data.

    @param [out] frame The returned data which depends on the provided idx.
    @param idx Determines the returned data inside image. The returned data can be the:
     - Decoded frame, idx = get(PROP_DECODED_FRAME_IDX).
     - Extra data if available, idx = get(PROP_EXTRA_DATA_INDEX).
     - Raw encoded data package.  To retrieve package i,  idx = get(PROP_RAW_PACKAGES_BASE_INDEX) + i with i < get(PROP_NUMBER_OF_RAW_PACKAGES_SINCE_LAST_GRAB)
    @return `false` if no frames have been grabbed

    The method returns data associated with the current video source since the last call to grab() or the creation of the VideoReader. If no data is present
    the method returns false and the function returns an empty image.
     */
    virtual bool retrieve(OutputArray frame, const size_t idx = static_cast<size_t>(VideoReaderProps::PROP_DECODED_FRAME_IDX)) const = 0;

    /** @brief Returns previously grabbed encoded video data.

    @param [out] frame The encoded video data.
    @param idx Determines the returned data inside image. The returned data can be the:
     - Extra data if available, idx = get(PROP_EXTRA_DATA_INDEX).
     - Raw encoded data package.  To retrieve package i,  idx = get(PROP_RAW_PACKAGES_BASE_INDEX) + i with i < get(PROP_NUMBER_OF_RAW_PACKAGES_SINCE_LAST_GRAB)
    @return `false` if no frames have been grabbed

    The method returns data associated with the current video source since the last call to grab() or the creation of the VideoReader. If no data is present
    the method returns false and the function returns an empty image.
     */
    CV_WRAP inline bool retrieve(CV_OUT Mat& frame, const size_t idx) const {
        return retrieve(OutputArray(frame), idx);
    }

    /** @brief Returns the next video frame.

    @param [out] frame The video frame.  If grab() has not been called then this will be empty().
    @return `false` if no frames have been grabbed

    The method returns data associated with the current video source since the last call to grab(). If no data is present
    the method returns false and the function returns an empty image.
     */
    CV_WRAP inline bool retrieve(CV_OUT cuda::GpuMat& frame) const {
        return retrieve(OutputArray(frame));
    }

    /** @brief Sets a property in the VideoReader.

    @param propertyId Property identifier from cv::cudacodec::VideoReaderProps (eg. cv::cudacodec::VideoReaderProps::PROP_DECODED_FRAME_IDX,
    cv::cudacodec::VideoReaderProps::PROP_EXTRA_DATA_INDEX, ...).
    @param propertyVal Value of the property.
    @return `true` if the property has been set.
     */
    virtual bool set(const VideoReaderProps propertyId, const double propertyVal) = 0;
    CV_WRAP inline bool setVideoReaderProps(const VideoReaderProps propertyId, double propertyVal) {
        return set(propertyId, propertyVal);
    }

    /** @brief Set the desired ColorFormat for the frame returned by nextFrame()/retrieve().

    @param colorFormat Value of the ColorFormat.
    @param bitDepth Requested bit depth of the frame.
    @param planar Set to true for planar and false for packed color format.
    @return `true` unless the colorFormat is not supported.
     */
    CV_WRAP virtual bool set(const ColorFormat colorFormat, const BitDepth bitDepth = BitDepth::UNCHANGED, const bool planar = false) = 0;

    /** @brief Returns the specified VideoReader property

    @param propertyId Property identifier from cv::cudacodec::VideoReaderProps (eg. cv::cudacodec::VideoReaderProps::PROP_DECODED_FRAME_IDX,
    cv::cudacodec::VideoReaderProps::PROP_EXTRA_DATA_INDEX, ...).
    @param propertyVal
     - In: Optional value required for querying specific propertyId's, e.g. the index of the raw package to be checked for a key frame (cv::cudacodec::VideoReaderProps::PROP_LRF_HAS_KEY_FRAME).
     - Out: Value of the property.
    @return `true` unless the property is not supported.
    */
    virtual bool get(const VideoReaderProps propertyId, double& propertyVal) const = 0;
    CV_WRAP virtual bool getVideoReaderProps(const VideoReaderProps propertyId,  CV_OUT double& propertyValOut, double propertyValIn = 0) const = 0;

    /** @brief Retrieves the specified property used by the VideoSource.

    @param propertyId Property identifier from cv::VideoCaptureProperties (eg. cv::CAP_PROP_POS_MSEC, cv::CAP_PROP_POS_FRAMES, ...)
    or one from @ref videoio_flags_others.
    @param propertyVal Value for the specified property.

    @return `true` unless the property is unset set or not supported.
     */
    CV_WRAP virtual bool get(const int propertyId, CV_OUT double& propertyVal) const = 0;
};

/** @brief Interface for video demultiplexing. :

User can implement own demultiplexing by implementing this interface.
 */
class CV_EXPORTS_W RawVideoSource
{
public:
    virtual ~RawVideoSource() {}

    /** @brief Returns next packet with RAW video frame.

    @param data Pointer to frame data.
    @param size Size in bytes of current frame.
     */
    virtual bool getNextPacket(unsigned char** data, size_t* size) = 0;

    /** @brief Returns true if the last packet contained a key frame.
     */
    virtual bool lastPacketContainsKeyFrame() const { return false; }

    /** @brief Returns information about video file format.
    */
    virtual FormatInfo format() const = 0;

    /** @brief Updates the coded width and height inside format.
    */
    virtual void updateFormat(const FormatInfo& videoFormat) = 0;

    /** @brief Returns any extra data associated with the video source.

    @param extraData 1D cv::Mat containing the extra data if it exists.
     */
    virtual void getExtraData(cv::Mat& extraData) const = 0;

    /** @brief Retrieves the specified property used by the VideoSource.

    @param propertyId Property identifier from cv::VideoCaptureProperties (eg. cv::CAP_PROP_POS_MSEC, cv::CAP_PROP_POS_FRAMES, ...)
    or one from @ref videoio_flags_others.
    @param propertyVal Value for the specified property.

    @return `true` unless the property is unset set or not supported.
     */
    virtual bool get(const int propertyId, double& propertyVal) const = 0;

    /** @brief Retrieve the index of the first frame that will returned after construction.

    @return index of the index of the first frame that will returned after construction.

    @note To reduce the decoding overhead when initializing VideoReader to start its decoding from frame N, RawVideoSource should seek to the first valid key frame less than or equal to N and return that index here.
     */
    virtual int getFirstFrameIdx() const = 0;
};

/** @brief VideoReader initialization parameters
@param udpSource Remove validation which can cause VideoReader() to throw exceptions when reading from a UDP source.
@param allowFrameDrop Allow frames to be dropped when ingesting from a live capture source to prevent delay and eventual disconnection
when calls to nextFrame()/grab() cannot keep up with the source's fps.  Only use if delay and disconnection are a problem, i.e. not when decoding from
video files where setting this flag will cause frames to be unnecessarily discarded.
@param minNumDecodeSurfaces Minimum number of internal decode surfaces used by the hardware decoder.  NVDEC will automatically determine the minimum number of
surfaces it requires for correct functionality and optimal video memory usage but not necessarily for best performance, which depends on the design of the
overall application. The optimal number of decode surfaces (in terms of performance and memory utilization) should be decided by experimentation for each application,
but it cannot go below the number determined by NVDEC.
@param rawMode Allow the raw encoded data which has been read up until the last call to grab() to be retrieved by calling retrieve(rawData,RAW_DATA_IDX).
@param targetSz Post-processed size (width/height should be multiples of 2) of the output frame, defaults to the size of the encoded video source.
@param srcRoi Region of interest (x/width should be multiples of 4 and y/height multiples of 2) decoded from video source, defaults to the full frame.
@param targetRoi Region of interest (x/width should be multiples of 4 and y/height multiples of 2) within the output frame to copy and resize the decoded frame to,
defaults to the full frame.
@param enableHistogram Request output of decoded luma histogram \a hist from VideoReader::nextFrame(GpuMat& frame, GpuMat& hist, Stream& stream), if hardware supported.
@param firstFrameIdx Index of the first frame to seek to on initialization of the VideoReader.
*/
struct CV_EXPORTS_W_SIMPLE VideoReaderInitParams {
    CV_WRAP VideoReaderInitParams() : udpSource(false), allowFrameDrop(false), minNumDecodeSurfaces(0), rawMode(0), enableHistogram(false), firstFrameIdx(0){};
    CV_PROP_RW bool udpSource;
    CV_PROP_RW bool allowFrameDrop;
    CV_PROP_RW int minNumDecodeSurfaces;
    CV_PROP_RW bool rawMode;
    CV_PROP_RW cv::Size targetSz;
    CV_PROP_RW cv::Rect srcRoi;
    CV_PROP_RW cv::Rect targetRoi;
    CV_PROP_RW bool enableHistogram;
    CV_PROP_RW int firstFrameIdx;
};

/** @brief Creates video reader.

@param filename Name of the input video file.
@param sourceParams Pass through parameters for VideoCapure.  VideoCapture with the FFMpeg back end (CAP_FFMPEG) is used to parse the video input.
The `sourceParams` parameter allows to specify extra parameters encoded as pairs `(paramId_1, paramValue_1, paramId_2, paramValue_2, ...)`.
    See cv::VideoCaptureProperties
e.g. when streaming from an RTSP source CAP_PROP_OPEN_TIMEOUT_MSEC may need to be set.
@param params Initializaton parameters. See cv::cudacodec::VideoReaderInitParams.

FFMPEG is used to read videos. User can implement own demultiplexing with cudacodec::RawVideoSource
 */
CV_EXPORTS_W Ptr<VideoReader> createVideoReader(const String& filename, const std::vector<int>& sourceParams = {}, const VideoReaderInitParams params = VideoReaderInitParams());

/** @overload
@param source RAW video source implemented by user.
@param params Initializaton parameters. See cv::cudacodec::VideoReaderInitParams.
*/
CV_EXPORTS_W Ptr<VideoReader> createVideoReader(const Ptr<RawVideoSource>& source, const VideoReaderInitParams params = VideoReaderInitParams());

//! @}

}} // namespace cv { namespace cudacodec {

#endif /* OPENCV_CUDACODEC_HPP */
