OCCT

// Created on: 2016-04-01
// Created by: Anastasia BORISOVA
// Copyright (c) 2016 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef Image_VideoRecorder_HeaderFile_
#define Image_VideoRecorder_HeaderFile_

#include <Image_PixMap.hxx>
#include <TCollection_AsciiString.hxx>
#include <NCollection_DataMap.hxx>
#include <Standard_Transient.hxx>

// forward declarations
struct AVFormatContext;
struct AVCodecContext;
struct AVStream;
struct AVCodec;
struct AVFrame;
struct SwsContext;

// Undefine macro that clashes with name used by field of Image_VideoParams;
// this macro is defined in headers of older versions of libavutil
// (see definition of macro FF_API_PIX_FMT in version.h)
#ifdef PixelFormat
  #undef PixelFormat
#endif

//! Auxiliary structure defining video parameters.
//! Please refer to FFmpeg documentation for defining text values.
struct Image_VideoParams
{
  // clang-format off
  TCollection_AsciiString Format;           //!< [optional]  video format (container), if empty - will be determined from the file name
  TCollection_AsciiString VideoCodec;       //!< [optional]  codec identifier, if empty - default codec from file format will be used
  TCollection_AsciiString PixelFormat;      //!< [optional]  pixel format, if empty - default codec pixel format will be used
  // clang-format on
  int Width;  //!< [mandatory] video frame width
  int Height; //!< [mandatory] video frame height
  int FpsNum; //!< [mandatory] framerate numerator
  int FpsDen; //!< [mandatory] framerate denumerator
  NCollection_DataMap<TCollection_AsciiString, TCollection_AsciiString>
    VideoCodecParams; //!< map of advanced video codec parameters

  //! Empty constructor.
  Image_VideoParams()
      : Width(0),
        Height(0),
        FpsNum(0),
        FpsDen(1)
  {
  }

  //! Setup playback FPS.
  void SetFramerate(const int theNumerator, const int theDenominator)
  {
    FpsNum = theNumerator;
    FpsDen = theDenominator;
  }

  //! Setup playback FPS.
  //! For fixed-fps content, timebase should be 1/framerate and timestamp increments should be
  //! identical to 1.
  void SetFramerate(const int theValue)
  {
    FpsNum = theValue;
    FpsDen = 1;
  }
};

//! Video recording tool based on FFmpeg framework.
class Image_VideoRecorder : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Image_VideoRecorder, Standard_Transient)
public:
  //! Empty constructor.
  Standard_EXPORT Image_VideoRecorder();

  //! Destructor.
  Standard_EXPORT ~Image_VideoRecorder() override;

  //! Close the stream - stop recorder.
  Standard_EXPORT void Close();

  //! Open output stream - initialize recorder.
  //! @param[in] theFileName  video filename
  //! @param[in] theParams    video parameters
  Standard_EXPORT bool Open(const char* theFileName, const Image_VideoParams& theParams);

  //! Access RGBA frame, should NOT be re-initialized outside.
  //! Note that image is expected to have upper-left origin.
  Image_PixMap& ChangeFrame() { return myImgSrcRgba; }

  //! Return current frame index.
  int64_t FrameCount() const { return myFrameCount; }

  //! Push new frame, should be called after Open().
  bool PushFrame() { return writeVideoFrame(false); }

protected:
  //! Wrapper for av_strerror().
  Standard_EXPORT TCollection_AsciiString formatAvError(const int theError) const;

  //! Get codec context compatible with both old and new FFmpeg API.
  Standard_EXPORT AVCodecContext* getCodecContext() const;

  //! Append video stream.
  //! theParams[in]      video parameters
  //! theDefCodecId[in]  identifier of codec managed by FFmpeg library (AVCodecID enum)
  Standard_EXPORT bool addVideoStream(const Image_VideoParams& theParams, const int theDefCodecId);

  //! Open video codec.
  Standard_EXPORT bool openVideoCodec(const Image_VideoParams& theParams);

  //! Write new video frame.
  Standard_EXPORT bool writeVideoFrame(const bool theToFlush);

protected:
  //! AVRational alias.
  struct VideoRational
  {
    int num; //!< numerator
    int den; //!< denominator
  };

protected:
  AVFormatContext* myAVContext;   //!< video context
  AVStream*        myVideoStream; //!< video stream
  AVCodec*         myVideoCodec;  //!< video codec
  AVCodecContext*  myCodecCtx;    //!< codec context (for FFmpeg 5.0+)
  AVFrame*         myFrame;       //!< frame to record
  SwsContext*      myScaleCtx;    //!< scale context for conversion from RGBA to YUV

  Image_PixMap  myImgSrcRgba; //!< input RGBA image
  VideoRational myFrameRate;  //!< video framerate
  int64_t       myFrameCount; //!< current frame index
};

#endif // Image_VideoRecorder_HeaderFile_