1748 Video Support in V1.0: part 1/3 : support MatroskaViedo

exiv2.md

@@ -117,8 +117,8 @@ and see if `enable_bmff=1`.
 - Naked codestream JXL files do not contain Exif, IPTC or XMP metadata.
 
 - Support of video files is limited. Currently **exiv2** only has some
-  rudimentary support to read metadata from quicktime based video files (e.g.
-  .MOV/.MP4).
+  rudimentary support to read metadata from quicktime and matroskavideo based video files (e.g.
+  .MOV/.MP4, MKV)
 
 
 [TOC](#TOC)

include/exiv2/image_types.hpp

@@ -35,6 +35,7 @@ enum class ImageType {
   webp,
   xmp,  ///< XMP sidecar files
   qtime,
+  mkv,
 };
 }  // namespace Exiv2
 

include/exiv2/matroskavideo.hpp

@@ -0,0 +1,196 @@
+// ***************************************************************** -*- C++ -*-
+/*
+ * Copyright (C) 2004-2021 Exiv2 authors
+ * This program is part of the Exiv2 distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef MATROSKAVIDEO_HPP_
+#define MATROSKAVIDEO_HPP_
+
+// *****************************************************************************
+#include "exiv2lib_export.h"
+
+// included header files
+#include "image.hpp"
+
+// *****************************************************************************
+// namespace extensions
+namespace Exiv2 {
+
+/*!
+  @brief Helper structure for the Matroska tags lookup table.
+ */
+
+// *****************************************************************************
+// class definitions
+namespace Internal {
+
+enum matroskaTypeEnum : char {
+  String = 's',
+  Integer = 'i',
+  UInteger = 'u',
+  Date = 'd',
+  InternalField = 'n',
+  Boolean = 'o',
+  Binary = 'b',
+  Master = 'm',
+  Float = 'f',
+  Utf8 = '8',
+  UndefinedType = 'z'
+
+};
+
+enum matroskaProcessEnum : char { Process = 'p', Skip = 's', Composite = 'c', Undefined = 'u' };
+
+struct MatroskaTag {
+  uint64_t _id;
+  std::string _label;
+  matroskaTypeEnum _type;
+  matroskaProcessEnum _process;
+
+  MatroskaTag(uint64_t id, const std::string& label, matroskaTypeEnum type, matroskaProcessEnum process) :
+      _id(id), _label(label), _type(type), _process(process) {
+  }
+
+  MatroskaTag(uint64_t id, const std::string& label) :
+      _id(id), _label(label), _type(matroskaTypeEnum::UndefinedType), _process(matroskaProcessEnum::Undefined) {
+  }
+
+  bool isSkipped() const {
+    return _process == Skip;
+  }
+  bool isComposite() const {
+    return _process == Composite;
+  }
+  void dump(std::ostream& os) const {
+    os << " MatroskaTag "
+       << " id: [0x" << std::hex << _id << "] label:[" << _label << "] type:[" << _type << "] process :[" << _process
+       << "]\n";
+  }
+};
+
+/// @brief  Utility function to search into std::array of pairs
+/// @return the searched pair if exist,else nullptr
+template <size_t N>
+[[nodiscard]] const MatroskaTag* findTag(const std::array<MatroskaTag, N>& src, const uint64_t& key) {
+  const auto rc = std::find_if(src.begin(), src.end(), [&key](const MatroskaTag& tag) { return tag._id == key; });
+  // the return value is of type "const MatroskaTag*", so we return the adress of the content of the input
+  // iterator return by find_if
+  return rc == std::end(src) ? nullptr : &(*rc);
+}
+
+}  // namespace Internal
+
+/*!
+  @brief Class to access Matroska video files.
+ */
+class EXIV2API MatroskaVideo : public Image {
+ public:
+  //! @name Creators
+  //@{
+  /*!
+    @brief Constructor for a Matroska video. Since the constructor
+        can not return a result, callers should check the good() method
+        after object construction to determine success or failure.
+    @param io An auto-pointer that owns a BasicIo instance used for
+        reading and writing image metadata. \b Important: The constructor
+        takes ownership of the passed in BasicIo instance through the
+        auto-pointer. Callers should not continue to use the BasicIo
+        instance after it is passed to this method. Use the Image::io()
+        method to get a temporary reference.
+   */
+  explicit MatroskaVideo(BasicIo::UniquePtr io);
+
+  //! Copy constructor
+  MatroskaVideo(const MatroskaVideo& rhs) = delete;
+  //! Assignment operator
+  MatroskaVideo& operator=(const MatroskaVideo& rhs) = delete;
+  //@}
+
+  //! @name Manipulators
+  //@{
+  void readMetadata() override;
+  void writeMetadata() override;
+  //@}
+
+  //! @name Accessors
+  //@{
+  [[nodiscard]] std::string mimeType() const override;
+  //@}
+
+ protected:
+  /*!
+    @brief Function used to calulate the size of a block.
+        This information is only stored in one byte.
+        The size of the block is calculated by counting
+        the number of leading zeros in the binary code of the byte.
+        Size = (No. of leading zeros + 1) bytes
+    @param b The byte, which stores the information to calculate the size
+    @return Return the size of the block.
+   */
+  [[nodiscard]] uint32_t findBlockSize(byte b);
+  /*!
+    @brief Check for a valid tag and decode the block at the current IO position.
+        Calls contentManagement() or skips to next tag, if required.
+   */
+  void decodeBlock();
+  /*!
+    @brief Interpret tag information, and save it in the respective XMP container.
+    @param mt Pointer to current tag,
+    @param buf Pointer to the memory area with the tag information.
+    @param size Size of \em buf.
+   */
+
+  void decodeInternalTags(const Internal::MatroskaTag* tag, const byte* buf, size_t size);
+  void decodeStringTags(const Internal::MatroskaTag* tag, const byte* buf);
+  void decodeIntegerTags(const Internal::MatroskaTag* tag, const byte* buf, size_t size);
+  void decodeBooleanTags(const Internal::MatroskaTag* tag, const byte* buf, size_t size);
+  void decodeDateTags(const Internal::MatroskaTag* tag, const byte* buf, size_t size);
+  void decodeFloatTags(const Internal::MatroskaTag* tag, const byte* buf, size_t size);
+  /*!Internal::
+    @brief Calculates Aspect Ratio of a video, and stores it in the
+        respective XMP container.
+   */
+  void aspectRatio();
+
+ private:
+  //! Variable to check the end of metadata traversing.
+  bool continueTraversing_;
+  //! Variable to store height and width of a video frame.
+  uint64_t height_;
+  uint64_t width_;
+  uint32_t track_count_;
+  double time_code_scale_ = 1.0;
+  uint64_t stream_ = 0;
+
+  static constexpr double bytesMB = 1048576;
+
+};  // class MatroskaVideo
+
+// *****************************************************************************
+/*!
+  @brief Create a new MatroskaVideo instance and return an auto-pointer to it.
+      Caller owns the returned object and the auto-pointer ensures that
+      it will be deleted.
+ */
+EXIV2API Image::UniquePtr newMkvInstance(BasicIo::UniquePtr io, bool create);
+
+//! Check if the file iIo is a Matroska Video.
+EXIV2API bool isMkvType(BasicIo& iIo, bool advance);
+
+}  // namespace Exiv2
+
+#endif  // #ifndef MATROSKAVIDEO_HPP_

src/CMakeLists.txt

@@ -61,6 +61,7 @@ set(PUBLIC_HEADERS
     ../include/exiv2/iptc.hpp
     ../include/exiv2/jp2image.hpp
     ../include/exiv2/jpgimage.hpp
+    ../include/exiv2/matroskavideo.hpp
     ../include/exiv2/metadatum.hpp
     ../include/exiv2/mrwimage.hpp
     ../include/exiv2/orfimage.hpp
@@ -105,6 +106,7 @@ add_library( exiv2lib
     iptc.cpp
     jp2image.cpp
     jpgimage.cpp
+    matroskavideo.cpp
     metadatum.cpp
     mrwimage.cpp
     orfimage.cpp

src/image.cpp

@@ -25,6 +25,7 @@
 #include "bmpimage.hpp"
 #include "gifimage.hpp"
 #include "jp2image.hpp"
+#include "matroskavideo.hpp"
 #include "nikonmn_int.hpp"
 #include "orfimage.hpp"
 #include "pgfimage.hpp"
@@ -100,6 +101,8 @@ constexpr auto registry = std::array{
     // needs to be before bmff because some ftyp files are handled as qt and
     // the rest should fall through to bmff
     Registry{ImageType::qtime, newQTimeInstance, isQTimeType, amRead, amNone, amRead, amNone},
+    Registry{ImageType::mkv, newMkvInstance, isMkvType, amRead, amNone, amRead, amNone},
+
 #ifdef EXV_ENABLE_BMFF
     Registry{ImageType::bmff, newBmffInstance, isBmffType, amRead, amRead, amRead, amNone},
 #endif  // EXV_ENABLE_BMFF