diff --git a/bindings/c/CMakeLists.txt b/bindings/c/CMakeLists.txt
index 34c8993c..d825fde8 100644
--- a/bindings/c/CMakeLists.txt
+++ b/bindings/c/CMakeLists.txt
@@ -63,6 +63,12 @@ if(WITH_SHORTEN)
     ${CMAKE_CURRENT_SOURCE_DIR}/../../taglib/shorten
   )
 endif()
+if(WITH_MATROSKA)
+  set(tag_c_HDR_DIRS ${tag_c_HDR_DIRS}
+    ${CMAKE_CURRENT_SOURCE_DIR}/../../taglib/matroska
+    ${CMAKE_CURRENT_SOURCE_DIR}/../../taglib/matroska/ebml
+  )
+endif()
 include_directories(${tag_c_HDR_DIRS})
 
 set(tag_c_HDRS tag_c.h)
diff --git a/bindings/c/tag_c.cpp b/bindings/c/tag_c.cpp
index 35453a63..48afec7d 100644
--- a/bindings/c/tag_c.cpp
+++ b/bindings/c/tag_c.cpp
@@ -80,6 +80,9 @@
 #ifdef TAGLIB_WITH_SHORTEN
 #include "shortenfile.h"
 #endif
+#ifdef TAGLIB_WITH_MATROSKA
+#include "matroskafile.h"
+#endif
 
 using namespace TagLib;
 
@@ -241,6 +244,11 @@ TagLib_File *taglib_file_new_type_any_char(const T *filename, TagLib_File_Type t
   case TagLib_File_SHORTEN:
     file = new Shorten::File(filename);
     break;
+#endif
+#ifdef TAGLIB_WITH_MATROSKA
+  case TagLib_File_MATROSKA:
+    file = new Matroska::File(filename);
+    break;
 #endif
   default:
     break;
diff --git a/bindings/c/tag_c.h b/bindings/c/tag_c.h
index 88c8d67b..59f7163e 100644
--- a/bindings/c/tag_c.h
+++ b/bindings/c/tag_c.h
@@ -132,7 +132,8 @@ typedef enum {
   TagLib_File_Opus,
   TagLib_File_DSF,
   TagLib_File_DSDIFF,
-  TagLib_File_SHORTEN
+  TagLib_File_SHORTEN,
+  TagLib_File_MATROSKA
 } TagLib_File_Type;
 
 /*!
diff --git a/taglib/fileref.cpp b/taglib/fileref.cpp
index 701f30a7..a8c3404f 100644
--- a/taglib/fileref.cpp
+++ b/taglib/fileref.cpp
@@ -296,6 +296,10 @@ namespace
     else if(Shorten::File::isSupported(stream))
       file = new Shorten::File(stream, readAudioProperties, audioPropertiesStyle);
 #endif
+#ifdef TAGLIB_WITH_MATROSKA
+    else if(Matroska::File::isSupported(stream))
+      file = new Matroska::File(stream, readAudioProperties, audioPropertiesStyle);
+#endif
 
     // isSupported() only does a quick check, so double check the file here.
 
@@ -520,6 +524,11 @@ StringList FileRef::defaultFileExtensions()
 #ifdef TAGLIB_WITH_SHORTEN
   l.append("shn");
 #endif
+#ifdef TAGLIB_WITH_MATROSKA
+  l.append("mkv");
+  l.append("mka");
+  l.append("webm");
+#endif
 
   return l;
 }
diff --git a/taglib/matroska/ebml/ebmlmksegment.h b/taglib/matroska/ebml/ebmlmksegment.h
index 41f68983..f34df50c 100644
--- a/taglib/matroska/ebml/ebmlmksegment.h
+++ b/taglib/matroska/ebml/ebmlmksegment.h
@@ -51,11 +51,9 @@ namespace TagLib {
       Matroska::Segment* parseSegment();
 
     private:
-      offset_t dataOffset = 0;
       MkTags *tags = nullptr;
       MkAttachments *attachments = nullptr;
       MkSeekHead *seekHead = nullptr;
-
     };
   }
 }
diff --git a/taglib/matroska/ebml/ebmlstringelement.cpp b/taglib/matroska/ebml/ebmlstringelement.cpp
index f7bb4430..7c272352 100644
--- a/taglib/matroska/ebml/ebmlstringelement.cpp
+++ b/taglib/matroska/ebml/ebmlstringelement.cpp
@@ -54,7 +54,7 @@ ByteVector EBML::StringElement<t>::render()
   std::string string = value.to8Bit(t == String::UTF8);
   dataSize = string.size();
   buffer.append(renderVINT(dataSize, 0));
-  buffer.append(ByteVector(string.data(), dataSize));
+  buffer.append(ByteVector(string.data(), static_cast<unsigned int>(dataSize)));
   return buffer;
 }
 template ByteVector EBML::StringElement<String::UTF8>::render();
diff --git a/taglib/matroska/ebml/ebmlutils.cpp b/taglib/matroska/ebml/ebmlutils.cpp
index cd41667c..5c288b8b 100644
--- a/taglib/matroska/ebml/ebmlutils.cpp
+++ b/taglib/matroska/ebml/ebmlutils.cpp
@@ -64,7 +64,7 @@ std::pair<int, T> EBML::readVINT(File &file)
 
   if(nb_bytes > 1)
     buffer.append(file.readBlock(nb_bytes - 1));
-  int bits_to_shift = (sizeof(T) * 8) - (7 * nb_bytes);
+  int bits_to_shift = static_cast<int>(sizeof(T) * 8) - (7 * nb_bytes);
   offset_t mask = 0xFFFFFFFFFFFFFFFF >> bits_to_shift;
   return { nb_bytes, static_cast<T>(buffer.toLongLong(true)) & mask };
 }
@@ -83,7 +83,7 @@ std::pair<int, T> EBML::parseVINT(const ByteVector &buffer)
   if(!numBytes)
     return {0, 0};
 
-  int bits_to_shift = (sizeof(T) * 8) - (7 * numBytes);
+  int bits_to_shift = static_cast<int>(sizeof(T) * 8) - (7 * numBytes);
   offset_t mask = 0xFFFFFFFFFFFFFFFF >> bits_to_shift;
   return { numBytes, static_cast<T>(buffer.toLongLong(true)) & mask };
 }
diff --git a/taglib/matroska/ebml/ebmlvoidelement.cpp b/taglib/matroska/ebml/ebmlvoidelement.cpp
index 2eae2fed..9cb54f23 100644
--- a/taglib/matroska/ebml/ebmlvoidelement.cpp
+++ b/taglib/matroska/ebml/ebmlvoidelement.cpp
@@ -32,12 +32,12 @@ ByteVector EBML::VoidElement::render()
   offset_t bytesNeeded = targetSize;
   ByteVector buffer = renderId();
   bytesNeeded -= buffer.size();
-  sizeLength = std::min(bytesNeeded, static_cast<offset_t>(8));
+  sizeLength = static_cast<int>(std::min(bytesNeeded, static_cast<offset_t>(8)));
   bytesNeeded -= sizeLength;
   dataSize = bytesNeeded;
   buffer.append(renderVINT(dataSize, sizeLength));
   if (dataSize)
-    buffer.append(ByteVector(dataSize, 0));
+    buffer.append(ByteVector(static_cast<unsigned int>(dataSize), 0));
 
   return buffer;
 }
diff --git a/taglib/matroska/matroskaattachedfile.h b/taglib/matroska/matroskaattachedfile.h
index acb62839..142196b3 100644
--- a/taglib/matroska/matroskaattachedfile.h
+++ b/taglib/matroska/matroskaattachedfile.h
@@ -48,10 +48,10 @@ namespace TagLib {
 
     private:
       class AttachedFilePrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<AttachedFilePrivate> d;
-
     };
   }
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/taglib/matroska/matroskaattachments.h b/taglib/matroska/matroskaattachments.h
index dde699a0..7f75bb74 100644
--- a/taglib/matroska/matroskaattachments.h
+++ b/taglib/matroska/matroskaattachments.h
@@ -55,10 +55,10 @@ namespace TagLib {
       friend class EBML::MkAttachments;
       friend class Matroska::File;
       class AttachmentsPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<AttachmentsPrivate> d;
-
     };
   }
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/taglib/matroska/matroskaelement.cpp b/taglib/matroska/matroskaelement.cpp
index 5d406a38..76181429 100644
--- a/taglib/matroska/matroskaelement.cpp
+++ b/taglib/matroska/matroskaelement.cpp
@@ -141,7 +141,7 @@ bool Matroska::Element::sizeChanged(Element &caller, offset_t delta)
   return true;
 }
 
-bool Matroska::Element::offsetChanged(Element &caller, offset_t delta)
+bool Matroska::Element::offsetChanged(Element &, offset_t)
 {
   // Most elements don't need to handle this
   return true;
diff --git a/taglib/matroska/matroskaelement.h b/taglib/matroska/matroskaelement.h
index d8697931..ec3e7863 100644
--- a/taglib/matroska/matroskaelement.h
+++ b/taglib/matroska/matroskaelement.h
@@ -64,8 +64,8 @@ namespace TagLib {
 
     private:
       class ElementPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<ElementPrivate> e;
-
     };
     namespace ElementIDs {
       inline constexpr Element::ID MkTags        = 0x1254C367;
diff --git a/taglib/matroska/matroskafile.cpp b/taglib/matroska/matroskafile.cpp
index dc9f2f6a..eabc96e4 100644
--- a/taglib/matroska/matroskafile.cpp
+++ b/taglib/matroska/matroskafile.cpp
@@ -55,7 +55,22 @@ public:
   Segment *segment = nullptr;
 };
 
-Matroska::File::File(FileName file, bool readProperties)
+////////////////////////////////////////////////////////////////////////////////
+// static members
+////////////////////////////////////////////////////////////////////////////////
+
+bool Matroska::File::isSupported(IOStream *)
+{
+  // TODO implement
+  return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// public members
+////////////////////////////////////////////////////////////////////////////////
+
+Matroska::File::File(FileName file, bool readProperties,
+                     Properties::ReadStyle readStyle)
 : TagLib::File(file),
   d(std::make_unique<FilePrivate>())
 {
@@ -64,10 +79,11 @@ Matroska::File::File(FileName file, bool readProperties)
     setValid(false);
     return;
   }
-  read(readProperties);
+  read(readProperties, readStyle);
 }
 
-Matroska::File::File(IOStream *stream, bool readProperties)
+Matroska::File::File(IOStream *stream, bool readProperties,
+                     Properties::ReadStyle readStyle)
 : TagLib::File(stream),
   d(std::make_unique<FilePrivate>())
 {
@@ -76,7 +92,7 @@ Matroska::File::File(IOStream *stream, bool readProperties)
     setValid(false);
     return;
   }
-  read(readProperties);
+  read(readProperties, readStyle);
 }
 
 Matroska::File::~File() = default;
@@ -108,7 +124,7 @@ Matroska::Attachments* Matroska::File::attachments(bool create) const
   }
 }
 
-void Matroska::File::read(bool readProperties)
+void Matroska::File::read(bool, Properties::ReadStyle)
 {
   offset_t fileLength = length();
 
@@ -139,7 +155,7 @@ void Matroska::File::read(bool readProperties)
     setValid(false);
     return;
   }
-  
+
   // Parse the elements
   d->segment = segment->parseSegment();
   d->seekHead = segment->parseSeekHead();
diff --git a/taglib/matroska/matroskafile.h b/taglib/matroska/matroskafile.h
index a8e99e19..b368412c 100644
--- a/taglib/matroska/matroskafile.h
+++ b/taglib/matroska/matroskafile.h
@@ -24,6 +24,7 @@
 #include "taglib_export.h"
 #include "tfile.h"
 #include "tag.h"
+#include "matroskaproperties.h"
 
 
 namespace TagLib {
@@ -34,8 +35,10 @@ namespace TagLib {
     class TAGLIB_EXPORT File : public TagLib::File
     {
     public:
-      File(FileName file, bool readProperties = true);
-      File(IOStream *stream, bool readProperties = true);
+      File(FileName file, bool readProperties = true,
+           Properties::ReadStyle readStyle = Properties::Average);
+      File(IOStream *stream, bool readProperties = true,
+           Properties::ReadStyle readStyle = Properties::Average);
       ~File() override;
       File(const File &) = delete;
       File &operator=(const File &) = delete;
@@ -46,19 +49,23 @@ namespace TagLib {
       bool save() override;
       //PropertyMap properties() const override { return PropertyMap(); }
       //void removeUnsupportedProperties(const StringList &properties) override { }
-    private:
-      void read(bool readProperties);
-      class FilePrivate;
-      std::unique_ptr<FilePrivate> d;
 
+      /*!
+       * Returns whether or not the given \a stream can be opened as a Matroska
+       * file.
+       *
+       * \note This method is designed to do a quick check.  The result may
+       * not necessarily be correct.
+       */
+      static bool isSupported(IOStream *stream);
+
+    private:
+      void read(bool readProperties, Properties::ReadStyle readStyle);
+      class FilePrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
+      std::unique_ptr<FilePrivate> d;
     };
   }
 }
 
-
-
-
-
-
-
- #endif
\ No newline at end of file
+ #endif
diff --git a/taglib/matroska/matroskaproperties.cpp b/taglib/matroska/matroskaproperties.cpp
new file mode 100644
index 00000000..3712856e
--- /dev/null
+++ b/taglib/matroska/matroskaproperties.cpp
@@ -0,0 +1,76 @@
+/***************************************************************************
+    copyright            : (C) 2025 by Urs Fleisch
+    email                : ufleisch@users.sourceforge.net
+ ***************************************************************************/
+
+/***************************************************************************
+ *   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.                     *
+ *                                                                         *
+ *   This library 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     *
+ *   Lesser General Public License for more details.                       *
+ *                                                                         *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with this library; if not, write to the Free Software   *
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA         *
+ *   02110-1301  USA                                                       *
+ *                                                                         *
+ *   Alternatively, this file is available under the Mozilla Public        *
+ *   License Version 1.1.  You may obtain a copy of the License at         *
+ *   http://www.mozilla.org/MPL/                                           *
+ ***************************************************************************/
+
+#include "matroskaproperties.h"
+
+using namespace TagLib;
+
+class Matroska::Properties::PropertiesPrivate
+{
+public:
+  int length { 0 };
+  int bitrate { 0 };
+  int sampleRate { 0 };
+  int bitsPerSample { 0 };
+  int channels { 0 };
+};
+
+Matroska::Properties::Properties(File *file, ReadStyle style) :
+  AudioProperties(style),
+  d(std::make_unique<PropertiesPrivate>())
+{
+  read(file);
+}
+
+Matroska::Properties::~Properties() = default;
+
+int Matroska::Properties::lengthInMilliseconds() const
+{
+  return d->length;
+}
+
+int Matroska::Properties::bitrate() const
+{
+  return d->bitrate;
+}
+
+int Matroska::Properties::sampleRate() const
+{
+  return d->sampleRate;
+}
+
+int Matroska::Properties::channels() const
+{
+  return d->channels;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// private members
+////////////////////////////////////////////////////////////////////////////////
+
+void Matroska::Properties::read(File *file)
+{
+  // TODO implement.
+}
diff --git a/taglib/matroska/matroskaproperties.h b/taglib/matroska/matroskaproperties.h
index a3a735f3..33340be6 100644
--- a/taglib/matroska/matroskaproperties.h
+++ b/taglib/matroska/matroskaproperties.h
@@ -27,25 +27,17 @@
 
 namespace TagLib {
 
-  namespace MPEG {
+  namespace Matroska {
 
     class File;
 
-    //! An implementation of audio property reading for MP3
-
-    /*!
-     * This reads the data from an MPEG Layer III stream found in the
-     * AudioProperties API.
-     */
-
+    //! An implementation of Matroska audio properties
     class TAGLIB_EXPORT Properties : public AudioProperties
     {
     public:
 
-      /*!
-       * Destroys this MPEG Properties instance.
-       */
-      ~Properties() override {}
+      Properties(File *file, ReadStyle style = Average);
+      ~Properties() override;
 
       Properties(const Properties &) = delete;
       Properties &operator=(const Properties &) = delete;
@@ -55,29 +47,31 @@ namespace TagLib {
        *
        * \see lengthInSeconds()
        */
-      int lengthInMilliseconds() const override {}
+      int lengthInMilliseconds() const override;
 
       /*!
        * Returns the average bit rate of the file in kb/s.
        */
-      int bitrate() const override {}
+      int bitrate() const override;
 
       /*!
        * Returns the sample rate in Hz.
        */
-      int sampleRate() const override {}
+      int sampleRate() const override;
 
       /*!
        * Returns the number of audio channels.
        */
-      int channels() const override {}
+      int channels() const override;
 
     private:
+      void read(File *file);
 
       class PropertiesPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<PropertiesPrivate> d;
     };
-  }  // namespace MPEG
+  }  // namespace Matroska
 }  // namespace TagLib
 
 #endif
diff --git a/taglib/matroska/matroskasegment.cpp b/taglib/matroska/matroskasegment.cpp
index f047e1b9..6afcac71 100644
--- a/taglib/matroska/matroskasegment.cpp
+++ b/taglib/matroska/matroskasegment.cpp
@@ -25,12 +25,12 @@ using namespace TagLib;
 
 bool Matroska::Segment::render()
 {
-  auto data = EBML::renderVINT(dataSize, sizeLength);
+  auto data = EBML::renderVINT(dataSize, static_cast<int>(sizeLength));
   if (data.size() != sizeLength) {
     sizeLength = 8;
     if (!emitSizeChanged(sizeLength - data.size()))
       return false;
-    data = EBML::renderVINT(dataSize, sizeLength);
+    data = EBML::renderVINT(dataSize, static_cast<int>(sizeLength));
     if (data.size() != sizeLength)
       return false;
   }
@@ -38,8 +38,8 @@ bool Matroska::Segment::render()
   return true;
 }
 
-bool Matroska::Segment::sizeChanged(Element &caller, offset_t delta)
+bool Matroska::Segment::sizeChanged(Element &, offset_t delta)
 {
   dataSize += delta;
   return true;
-} 
\ No newline at end of file
+}
diff --git a/taglib/matroska/matroskasimpletag.h b/taglib/matroska/matroskasimpletag.h
index 74553a97..484decd5 100644
--- a/taglib/matroska/matroskasimpletag.h
+++ b/taglib/matroska/matroskasimpletag.h
@@ -54,6 +54,7 @@ namespace TagLib {
 
     private:
       class SimpleTagPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<SimpleTagPrivate> d;
 
     protected:
@@ -70,6 +71,7 @@ namespace TagLib {
 
     private:
       class SimpleTagStringPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<SimpleTagStringPrivate> dd;
     };
 
@@ -83,6 +85,7 @@ namespace TagLib {
 
     private:
       class SimpleTagBinaryPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<SimpleTagBinaryPrivate> dd;
     };
 
diff --git a/taglib/matroska/matroskatag.h b/taglib/matroska/matroskatag.h
index 2370faec..5424010e 100644
--- a/taglib/matroska/matroskatag.h
+++ b/taglib/matroska/matroskatag.h
@@ -125,6 +125,7 @@ namespace TagLib {
       bool setTag(const String &key, const String &value);
       const String* getTag(const String &key) const;
       class TagPrivate;
+      TAGLIB_MSVC_SUPPRESS_WARNING_NEEDS_TO_HAVE_DLL_INTERFACE
       std::unique_ptr<TagPrivate> d;
     };
   }
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 25c6e1da..2d4a0c5d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -65,6 +65,11 @@ IF(WITH_SHORTEN)
     ${CMAKE_CURRENT_SOURCE_DIR}/../taglib/shorten
   )
 ENDIF()
+IF(WITH_MATROSKA)
+  SET(test_HDR_DIRS ${test_HDR_DIRS}
+    ${CMAKE_CURRENT_SOURCE_DIR}/../taglib/matroska
+  )
+ENDIF()
 INCLUDE_DIRECTORIES(${test_HDR_DIRS})
 
 SET(test_runner_SRCS
@@ -152,6 +157,11 @@ IF(WITH_SHORTEN)
     test_shorten.cpp
   )
 ENDIF()
+IF(WITH_MATROSKA)
+  SET(test_runner_SRCS ${test_runner_SRCS}
+    test_matroska.cpp
+  )
+ENDIF()
 IF(BUILD_BINDINGS)
   SET(test_runner_SRCS ${test_runner_SRCS}
     test_tag_c.cpp
diff --git a/tests/test_fileref.cpp b/tests/test_fileref.cpp
index 5c3e4e0d..34adfd78 100644
--- a/tests/test_fileref.cpp
+++ b/tests/test_fileref.cpp
@@ -472,6 +472,11 @@ public:
 #endif
 #ifdef TAGLIB_WITH_SHORTEN
     CPPUNIT_ASSERT(extensions.contains("shn"));
+#endif
+#ifdef TAGLIB_WITH_MATROSKA
+    CPPUNIT_ASSERT(extensions.contains("mkv"));
+    CPPUNIT_ASSERT(extensions.contains("mka"));
+    CPPUNIT_ASSERT(extensions.contains("webm"));
 #endif
   }
 
diff --git a/tests/test_matroska.cpp b/tests/test_matroska.cpp
new file mode 100644
index 00000000..d1fc3c0a
--- /dev/null
+++ b/tests/test_matroska.cpp
@@ -0,0 +1,28 @@
+#include <string>
+#include <cstdio>
+
+#include "tbytevectorlist.h"
+#include "tpropertymap.h"
+#include "tag.h"
+#include "matroskafile.h"
+#include "plainfile.h"
+#include <cppunit/extensions/HelperMacros.h>
+#include "utils.h"
+
+using namespace std;
+using namespace TagLib;
+
+class TestMatroska : public CppUnit::TestFixture
+{
+  CPPUNIT_TEST_SUITE(TestMatroska);
+  CPPUNIT_TEST(testTags);
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  void testTags()
+  {
+    // TODO implement
+  }
+};
+
+CPPUNIT_TEST_SUITE_REGISTRATION(TestMatroska);
diff --git a/tests/test_sizes.cpp b/tests/test_sizes.cpp
index 0bf03cce..9bf0ee93 100644
--- a/tests/test_sizes.cpp
+++ b/tests/test_sizes.cpp
@@ -148,6 +148,11 @@
 #include "trueaudiofile.h"
 #include "trueaudioproperties.h"
 #endif
+#ifdef TAGLIB_WITH_MATROSKA
+#include "matroskafile.h"
+#include "matroskaproperties.h"
+#include "matroskatag.h"
+#endif
 
 #include <cppunit/extensions/HelperMacros.h>
 
@@ -297,6 +302,12 @@ public:
 #ifdef TAGLIB_WITH_TRUEAUDIO
         CPPUNIT_ASSERT_EQUAL(classSize(1, true), sizeof(TagLib::TrueAudio::File));
         CPPUNIT_ASSERT_EQUAL(classSize(1, true), sizeof(TagLib::TrueAudio::Properties));
+#endif
+#ifdef TAGLIB_WITH_MATROSKA
+        CPPUNIT_ASSERT_EQUAL(classSize(1, true), sizeof(TagLib::Matroska::File));
+        CPPUNIT_ASSERT_EQUAL(classSize(1, true), sizeof(TagLib::Matroska::Properties));
+        // TODO move non pimpl fields into private class.
+        // CPPUNIT_ASSERT_EQUAL(classSize(1, true), sizeof(TagLib::Matroska::Tag));
 #endif
     }