diff --git a/Rakefile b/Rakefile
index 48484af8f..d652c414e 100755
--- a/Rakefile
+++ b/Rakefile
@@ -687,7 +687,7 @@ end
   { :name => 'rmff',        :dir => 'lib/librmff'                                                                                            },
   { :name => 'pugixml',     :dir => 'lib/pugixml/src'                                                                                        },
   { :name => 'mpegparser',  :dir => 'src/mpegparser'                                                                                         },
-  { :name => 'mtxcommon',   :dir => [ 'src/common' ] + %w{chapters checksums compression strings tags xml}.collect { |e| "src/common/#{e}" } },
+  { :name => 'mtxcommon',   :dir => [ 'src/common' ] + FileList['src/common/*'].select { |e| FileTest.directory? e } },
   { :name => 'mtxinput',    :dir => 'src/input'                                                                                              },
   { :name => 'mtxoutput',   :dir => 'src/output'                                                                                             },
   { :name => 'mtxmerge',    :dir => 'src/merge',    :except => [ 'mkvmerge.cpp' ],                                                           },
diff --git a/src/common/common.cpp b/src/common/common.cpp
index 05f0488f5..432cd5edd 100644
--- a/src/common/common.cpp
+++ b/src/common/common.cpp
@@ -135,7 +135,7 @@ set_process_priority(int priority) {
   // If the lowest priority should be used and we're on Vista or later
   // then use background priority. This also selects a lower I/O
   // priority.
-  if ((-2 == priority) && (get_windows_version() >= WINDOWS_VERSION_VISTA)) {
+  if ((-2 == priority) && (mtx::sys::get_windows_version() >= WINDOWS_VERSION_VISTA)) {
     SetPriorityClass(GetCurrentProcess(), PROCESS_MODE_BACKGROUND_BEGIN);
     SetThreadPriority(GetCurrentThread(), THREAD_MODE_BACKGROUND_BEGIN);
     return;
@@ -189,7 +189,7 @@ mtx_common_init(std::string const &program_name,
 
   stereo_mode_c::init();
 
-  mtx::determine_path_to_current_executable(argv0 ? std::string{argv0} : std::string{});
+  mtx::sys::determine_path_to_current_executable(argv0 ? std::string{argv0} : std::string{});
 }
 
 std::string const &
diff --git a/src/common/extern_data.cpp b/src/common/extern_data.cpp
index 8085a91e2..9c4cfce5a 100644
--- a/src/common/extern_data.cpp
+++ b/src/common/extern_data.cpp
@@ -2670,7 +2670,7 @@ guess_mime_type_internal(std::string ext,
 # endif  // MAGIC_MIME_TYPE
 
 # ifdef SYS_WINDOWS
-  auto magic_filename = (mtx::get_installation_path() / "data" / "magic").string();
+  auto magic_filename = (mtx::sys::get_installation_path() / "data" / "magic").string();
   if (!m || (-1 == magic_load(m, magic_filename.c_str())))
     return guess_mime_type_by_ext(ext);
 # else  // defined(SYS_WINDOWS)
diff --git a/src/common/fs_sys_helpers.h b/src/common/fs_sys_helpers.h
index 47fe2d797..ac72469a6 100644
--- a/src/common/fs_sys_helpers.h
+++ b/src/common/fs_sys_helpers.h
@@ -15,14 +15,22 @@
 
 #include "common/common_pch.h"
 
+namespace mtx { namespace sys {
+
 int64_t get_current_time_millis();
 
+int system(std::string const &command);
+
+void determine_path_to_current_executable(std::string const &argv0);
+bfs::path get_current_exe_path(std::string const &argv0);
+bfs::path get_application_data_folder();
+bfs::path get_installation_path();
+
 std::string get_environment_variable(const std::string &key);
 
 #if defined(SYS_WINDOWS)
 
 bool get_registry_key_value(const std::string &key, const std::string &value_name, std::string &value);
-
 void set_environment_variable(const std::string &key, const std::string &value);
 
 #define WINDOWS_VERSION_UNKNOWN      0x00000000
@@ -38,13 +46,6 @@ unsigned int get_windows_version();
 
 #endif
 
-namespace mtx {
-
-int system(std::string const &command);
-void determine_path_to_current_executable(std::string const &argv0);
-bfs::path get_application_data_folder();
-bfs::path get_installation_path();
-
-}
+}}
 
 #endif
diff --git a/src/common/fs_sys_helpers/common.cpp b/src/common/fs_sys_helpers/common.cpp
new file mode 100644
index 000000000..fa3f12249
--- /dev/null
+++ b/src/common/fs_sys_helpers/common.cpp
@@ -0,0 +1,32 @@
+/*
+   mkvmerge -- utility for splicing together matroska files
+   from component media subtypes
+
+   Distributed under the GPL v2
+   see the file COPYING for details
+   or visit http://www.gnu.org/copyleft/gpl.html
+
+   OS dependant file system & system helper functions
+
+   Written by Moritz Bunkus <moritz@bunkus.org>
+*/
+
+#include "common/common_pch.h"
+
+#include "common/fs_sys_helpers.h"
+
+namespace mtx { namespace sys {
+
+static bfs::path s_current_executable_path;
+
+bfs::path
+get_installation_path() {
+  return s_current_executable_path;
+}
+
+void
+determine_path_to_current_executable(std::string const &argv0) {
+  s_current_executable_path = get_current_exe_path(argv0);
+}
+
+}}
diff --git a/src/common/fs_sys_helpers/unix.cpp b/src/common/fs_sys_helpers/unix.cpp
new file mode 100644
index 000000000..c67a57106
--- /dev/null
+++ b/src/common/fs_sys_helpers/unix.cpp
@@ -0,0 +1,113 @@
+/*
+   mkvmerge -- utility for splicing together matroska files
+   from component media subtypes
+
+   Distributed under the GPL v2
+   see the file COPYING for details
+   or visit http://www.gnu.org/copyleft/gpl.html
+
+   OS dependant file system & system helper functions
+
+   Written by Moritz Bunkus <moritz@bunkus.org>
+*/
+
+#include "common/common_pch.h"
+
+#if !defined(SYS_WINDOWS)
+
+#include <stdlib.h>
+#include <sys/time.h>
+
+#if defined(SYS_APPLE)
+# include <mach-o/dyld.h>
+#endif
+
+#include "common/error.h"
+#include "common/fs_sys_helpers.h"
+#include "common/strings/editing.h"
+#include "common/strings/utf8.h"
+
+namespace mtx { namespace sys {
+
+int64_t
+get_current_time_millis() {
+  struct timeval tv;
+  if (0 != gettimeofday(&tv, nullptr))
+    return -1;
+
+  return (int64_t)tv.tv_sec * 1000 + (int64_t)tv.tv_usec / 1000;
+}
+
+bfs::path
+get_application_data_folder() {
+  auto home = getenv("HOME");
+  if (!home)
+    return bfs::path{};
+
+  // If $HOME/.mkvtoolnix exists already then keep using it to avoid
+  // losing existing user configuration.
+  auto old_default_folder = bfs::path{home} / ".mkvtoolnix";
+  if (boost::filesystem::exists(old_default_folder))
+    return old_default_folder;
+
+  // If XDG_CONFIG_HOME is set then use that folder.
+  auto xdg_config_home = getenv("XDG_CONFIG_HOME");
+  if (xdg_config_home)
+    return bfs::path{xdg_config_home} / "mkvtoolnix";
+
+  // If all fails then use the XDG fallback folder for config files.
+  return bfs::path{home} / ".config" / "mkvtoolnix";
+}
+
+std::string
+get_environment_variable(std::string const &key) {
+  auto var = getenv(key.c_str());
+  return var ? var : "";
+}
+
+int
+system(std::string const &command) {
+  return ::system(command.c_str());
+}
+
+bfs::path
+get_current_exe_path(std::string const &argv0) {
+#if defined(SYS_APPLE)
+  std::string file_name;
+  file_name.resize(4000);
+
+  while (true) {
+    memset(&file_name[0], 0, file_name.size());
+    uint32_t size = file_name.size();
+    auto result   = _NSGetExecutablePath(&file_name[0], &size);
+    file_name.resize(size);
+
+    if (0 == result)
+      break;
+  }
+
+  return bfs::absolute(bfs::path{file_name}).parent_path();
+
+#else // SYS_APPLE
+  auto exe = bfs::path{"/proc/self/exe"};
+  if (bfs::exists(exe)) {
+    auto exe_path = bfs::read_symlink(exe);
+
+    // only make absolute if needed, to avoid crash in case the current dir is deleted (as bfs::absolute calls bfs::current_path here)
+    return (exe_path.is_absolute() ? exe_path : bfs::absolute(exe_path)).parent_path();
+  }
+
+  if (argv0.empty())
+    return bfs::current_path();
+
+  exe = bfs::absolute(argv0);
+  if (bfs::exists(exe))
+    return exe.parent_path();
+
+  return bfs::current_path();
+#endif
+}
+
+}}
+
+#endif  // !SYS_WINDOWS
diff --git a/src/common/fs_sys_helpers.cpp b/src/common/fs_sys_helpers/windows.cpp
similarity index 59%
rename from src/common/fs_sys_helpers.cpp
rename to src/common/fs_sys_helpers/windows.cpp
index 9c1a87a7b..9b06ee641 100644
--- a/src/common/fs_sys_helpers.cpp
+++ b/src/common/fs_sys_helpers/windows.cpp
@@ -13,50 +13,21 @@
 
 #include "common/common_pch.h"
 
+#if defined(SYS_WINDOWS)
+
+#include <io.h>
+#include <windows.h>
+#include <winreg.h>
+#include <direct.h>
+#include <shlobj.h>
+#include <sys/timeb.h>
+
 #include "common/error.h"
 #include "common/fs_sys_helpers.h"
 #include "common/strings/editing.h"
 #include "common/strings/utf8.h"
 
-#if defined(SYS_APPLE)
-# include <mach-o/dyld.h>
-#endif
-
-#if defined(SYS_WINDOWS)
-
-# include <io.h>
-# include <windows.h>
-# include <winreg.h>
-# include <direct.h>
-# include <shlobj.h>
-# include <sys/timeb.h>
-
-#else
-
-# include <stdlib.h>
-# include <sys/time.h>
-
-#endif
-
-static bfs::path s_current_executable_path;
-
-#if defined(SYS_WINDOWS)
-
-HANDLE
-CreateFileUtf8(LPCSTR lpFileName,
-               DWORD dwDesiredAccess,
-               DWORD dwShareMode,
-               LPSECURITY_ATTRIBUTES lpSecurityAttributes,
-               DWORD dwCreationDisposition,
-               DWORD dwFlagsAndAttributes,
-               HANDLE hTemplateFile) {
-  // convert the name to wide chars
-  wchar_t *wbuffer = win32_utf8_to_utf16(lpFileName);
-  HANDLE ret       = CreateFileW(wbuffer, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile);
-  delete []wbuffer;
-
-  return ret;
-}
+namespace mtx { namespace sys {
 
 int64_t
 get_current_time_millis() {
@@ -138,7 +109,7 @@ get_windows_version() {
 }
 
 bfs::path
-mtx::get_application_data_folder() {
+get_application_data_folder() {
   wchar_t szPath[MAX_PATH];
 
   if (SUCCEEDED(SHGetFolderPathW(nullptr, CSIDL_APPDATA | CSIDL_FLAG_CREATE, nullptr, 0, szPath)))
@@ -147,51 +118,8 @@ mtx::get_application_data_folder() {
   return bfs::path{};
 }
 
-#else // SYS_WINDOWS
-
-int64_t
-get_current_time_millis() {
-  struct timeval tv;
-  if (0 != gettimeofday(&tv, nullptr))
-    return -1;
-
-  return (int64_t)tv.tv_sec * 1000 + (int64_t)tv.tv_usec / 1000;
-}
-
-bfs::path
-mtx::get_application_data_folder() {
-  const char *home = getenv("HOME");
-  if (!home)
-    return bfs::path{};
-
-  // If $HOME/.mkvtoolnix exists already then keep using it to avoid
-  // losing existing user configuration.
-  auto old_default_folder = bfs::path{home} / ".mkvtoolnix";
-  if (boost::filesystem::exists(old_default_folder))
-    return old_default_folder;
-
-  // If XDG_CONFIG_HOME is set then use that folder.
-  auto xdg_config_home = getenv("XDG_CONFIG_HOME");
-  if (xdg_config_home)
-    return bfs::path{xdg_config_home} / "mkvtoolnix";
-
-  // If all fails then use the XDG fallback folder for config files.
-  return bfs::path{home} / ".config" / "mkvtoolnix";
-}
-
-std::string
-get_environment_variable(std::string const &key) {
-  auto var = getenv(key.c_str());
-  return var ? var : "";
-}
-
-#endif // SYS_WINDOWS
-
-namespace mtx {
-
 int
 system(std::string const &command) {
-#ifdef SYS_WINDOWS
   std::wstring wcommand = to_wide(command);
   auto mem              = memory_c::clone(wcommand.c_str(), (wcommand.length() + 1) * sizeof(wchar_t));
 
@@ -221,13 +149,9 @@ system(std::string const &command) {
 
   return !result ? -1 : 0;
 
-#else  // SYS_WINDOWS
-  return ::system(command.c_str());
-#endif  // SYS_WINDOWS
 }
 
-#if defined(SYS_WINDOWS)
-static bfs::path
+bfs::path
 get_current_exe_path(std::string const &) {
   std::wstring file_name;
   file_name.resize(4000);
@@ -246,59 +170,6 @@ get_current_exe_path(std::string const &) {
   return bfs::absolute(bfs::path{to_utf8(file_name)}).parent_path();
 }
 
-#elif defined(SYS_APPLE)
+}}
 
-static bfs::path
-get_current_exe_path(std::string const &) {
-  std::string file_name;
-  file_name.resize(4000);
-
-  while (true) {
-    memset(&file_name[0], 0, file_name.size());
-    uint32_t size = file_name.size();
-    auto result   = _NSGetExecutablePath(&file_name[0], &size);
-    file_name.resize(size);
-
-    if (0 == result)
-      break;
-  }
-
-  return bfs::absolute(bfs::path{file_name}).parent_path();
-}
-
-#else // Neither Windows nor Mac OS
-
-static bfs::path
-get_current_exe_path(std::string const &argv0) {
-  // Linux
-  auto exe = bfs::path{"/proc/self/exe"};
-  if (bfs::exists(exe)) {
-    auto exe_path = bfs::read_symlink(exe);
-
-    // only make absolute if needed, to avoid crash in case the current dir is deleted (as bfs::absolute calls bfs::current_path here)
-    return (exe_path.is_absolute() ? exe_path : bfs::absolute(exe_path)).parent_path();
-  }
-
-  if (argv0.empty())
-    return bfs::current_path();
-
-  exe = bfs::absolute(argv0);
-  if (bfs::exists(exe))
-    return exe.parent_path();
-
-  return bfs::current_path();
-}
-
-#endif
-
-bfs::path
-get_installation_path() {
-  return s_current_executable_path;
-}
-
-void
-determine_path_to_current_executable(std::string const &argv0) {
-  s_current_executable_path = get_current_exe_path(argv0);
-}
-
-}
+#endif  // SYS_WINDOWS
diff --git a/src/common/kax_file.cpp b/src/common/kax_file.cpp
index 9f9fa95b1..5b70ef11f 100644
--- a/src/common/kax_file.cpp
+++ b/src/common/kax_file.cpp
@@ -196,7 +196,7 @@ kax_file_c::resync_to_level1_element_internal(uint32_t wanted_id) {
   m_resync_start_pos = m_in->getFilePointer();
 
   uint32_t actual_id = m_in->read_uint32_be();
-  int64_t start_time = get_current_time_millis();
+  int64_t start_time = mtx::sys::get_current_time_millis();
   bool is_cluster_id = !wanted_id || (EBML_ID_VALUE(EBML_ID(KaxCluster)) == wanted_id); // 0 means: any level 1 element will do
 
   mxinfo(boost::format(Y("%1%: Error in the Matroska file structure at position %2%. Resyncing to the next level 1 element.\n"))
@@ -211,7 +211,7 @@ kax_file_c::resync_to_level1_element_internal(uint32_t wanted_id) {
     mxinfo(boost::format("kax_file::resync_to_level1_element(): starting at %1% potential ID %|2$08x|\n") % m_resync_start_pos % actual_id);
 
   while (m_in->getFilePointer() < m_file_size) {
-    int64_t now = get_current_time_millis();
+    int64_t now = mtx::sys::get_current_time_millis();
     if ((now - start_time) >= 10000) {
       mxinfo(boost::format("Still resyncing at position %1%.\n") % m_in->getFilePointer());
       start_time = now;
diff --git a/src/common/locale.cpp b/src/common/locale.cpp
index 28de7d1da..f0eecd747 100644
--- a/src/common/locale.cpp
+++ b/src/common/locale.cpp
@@ -317,7 +317,7 @@ get_local_charset() {
 std::string
 get_local_console_charset() {
 #if defined(SYS_WINDOWS)
-  if (get_windows_version() >= WINDOWS_VERSION_VISTA)
+  if (mtx::sys::get_windows_version() >= WINDOWS_VERSION_VISTA)
     return std::string("CP") + to_string(GetACP());
   return std::string("CP") + to_string(GetOEMCP());
 #else
diff --git a/src/common/logger.cpp b/src/common/logger.cpp
index b6fb1aebe..e982bccd0 100644
--- a/src/common/logger.cpp
+++ b/src/common/logger.cpp
@@ -24,7 +24,7 @@ static auto s_program_start_time = std::chrono::system_clock::now();
 
 logger_c::logger_c(bfs::path const &file_name)
   : m_file_name(file_name)
-  , m_log_start(get_current_time_millis())
+  , m_log_start(mtx::sys::get_current_time_millis())
 {
   if (!m_file_name.is_absolute())
     m_file_name = bfs::temp_directory_path() / m_file_name;
diff --git a/src/common/mm_io_win.cpp b/src/common/mm_io_win.cpp
index 707335cb6..6cd9bdc6b 100644
--- a/src/common/mm_io_win.cpp
+++ b/src/common/mm_io_win.cpp
@@ -34,14 +34,21 @@
 #include "common/strings/parsing.h"
 #include "common/strings/utf8.h"
 
-HANDLE
-CreateFileUtf8(LPCSTR lpFileName,
-               DWORD dwDesiredAccess,
-               DWORD dwShareMode,
-               LPSECURITY_ATTRIBUTES lpSecurityAttributes,
-               DWORD dwCreationDisposition,
-               DWORD dwFlagsAndAttributes,
-               HANDLE hTemplateFile);
+static HANDLE
+create_file_utf8(LPCSTR lpFileName,
+                 DWORD dwDesiredAccess,
+                 DWORD dwShareMode,
+                 LPSECURITY_ATTRIBUTES lpSecurityAttributes,
+                 DWORD dwCreationDisposition,
+                 DWORD dwFlagsAndAttributes,
+                 HANDLE hTemplateFile) {
+  // convert the name to wide chars
+  wchar_t *wbuffer = win32_utf8_to_utf16(lpFileName);
+  HANDLE ret       = CreateFileW(wbuffer, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile);
+  delete []wbuffer;
+
+  return ret;
+}
 
 mm_file_io_c::mm_file_io_c(const std::string &path,
                            const open_mode mode)
@@ -79,7 +86,7 @@ mm_file_io_c::mm_file_io_c(const std::string &path,
   if ((MODE_WRITE == mode) || (MODE_CREATE == mode))
     prepare_path(path);
 
-  m_file = (void *)CreateFileUtf8(path.c_str(), access_mode, share_mode, nullptr, disposition, 0, nullptr);
+  m_file = (void *)create_file_utf8(path.c_str(), access_mode, share_mode, nullptr, disposition, 0, nullptr);
   if (static_cast<HANDLE>(m_file) == INVALID_HANDLE_VALUE)
     throw mtx::mm_io::open_x{mtx::mm_io::make_error_code()};
 
diff --git a/src/common/translation.cpp b/src/common/translation.cpp
index aa270a56f..c87494081 100644
--- a/src/common/translation.cpp
+++ b/src/common/translation.cpp
@@ -131,11 +131,11 @@ translation_c::get_default_ui_locale() {
 
 #if defined(HAVE_LIBINTL_H)
 # if defined(SYS_WINDOWS)
-  std::string env_var = get_environment_variable("LC_MESSAGES");
+  std::string env_var = mtx::sys::get_environment_variable("LC_MESSAGES");
   if (!env_var.empty() && (-1 != look_up_translation(env_var)))
     return env_var;
 
-  env_var = get_environment_variable("LANG");
+  env_var = mtx::sys::get_environment_variable("LANG");
   if (!env_var.empty() && (-1 != look_up_translation(env_var)))
     return env_var;
 
@@ -250,7 +250,7 @@ init_locales(std::string locale) {
   }
 
 # if defined(SYS_WINDOWS)
-  set_environment_variable("LANGUAGE", "");
+  mtx::sys::set_environment_variable("LANGUAGE", "");
 
   if (!locale.empty()) {
     // The Windows system headers define LC_MESSAGES but
@@ -261,8 +261,8 @@ init_locales(std::string locale) {
     // modified by SetEnvironmentVariable() and the C library's cache
     // of said environment which is modified via _putenv().
 
-    set_environment_variable("LANG",        locale);
-    set_environment_variable("LC_MESSAGES", locale);
+    mtx::sys::set_environment_variable("LANG",        locale);
+    mtx::sys::set_environment_variable("LC_MESSAGES", locale);
 
     translation_c::set_active_translation(locale);
   }
@@ -273,7 +273,7 @@ init_locales(std::string locale) {
   std::locale::global(utf8_locale);
   boost::filesystem::path::imbue(utf8_locale);
 
-  locale_dir = g_cc_local_utf8->native((mtx::get_installation_path() / "locale").string());
+  locale_dir = g_cc_local_utf8->native((mtx::sys::get_installation_path() / "locale").string());
 
 # else  // SYS_WINDOWS
   std::string chosen_locale;
diff --git a/src/merge/cues.cpp b/src/merge/cues.cpp
index 6bc45660c..a81dcfc09 100644
--- a/src/merge/cues.cpp
+++ b/src/merge/cues.cpp
@@ -78,9 +78,9 @@ cues_c::write(mm_io_c &out,
   if (!m_points.size() || !g_cue_writing_requested)
     return;
 
-  // auto start = get_current_time_millis();
+  // auto start = mtx::sys::get_current_time_millis();
   sort();
-  // auto end_sort = get_current_time_millis();
+  // auto end_sort = mtx::sys::get_current_time_millis();
 
   // Need to write the (empty) cues element so that its position will
   // be set for indexing in g_kax_sh_main. Necessary because there's
@@ -126,7 +126,7 @@ cues_c::write(mm_io_c &out,
   m_codec_state_position_map.clear();
   m_num_cue_points_postprocessed = 0;
 
-  // auto end_all = get_current_time_millis();
+  // auto end_all = mtx::sys::get_current_time_millis();
   // mxinfo(boost::format("dur sort %1% write %2% total %3%\n") % (end_sort - start) % (end_all - end_sort) % (end_all - start));
 }
 
diff --git a/src/merge/mkvmerge.cpp b/src/merge/mkvmerge.cpp
index baddde39c..a781ae181 100644
--- a/src/merge/mkvmerge.cpp
+++ b/src/merge/mkvmerge.cpp
@@ -2511,7 +2511,7 @@ main(int argc,
 
   parse_args(args);
 
-  int64_t start = get_current_time_millis();
+  int64_t start = mtx::sys::get_current_time_millis();
 
   add_filelists_for_playlists();
   create_readers();
@@ -2545,7 +2545,7 @@ main(int argc,
             % ex.what() % ex.error());
   }
 
-  mxinfo(boost::format(Y("Muxing took %1%.\n")) % create_minutes_seconds_time_string((get_current_time_millis() - start + 500) / 1000, true));
+  mxinfo(boost::format(Y("Muxing took %1%.\n")) % create_minutes_seconds_time_string((mtx::sys::get_current_time_millis() - start + 500) / 1000, true));
 
   cleanup();
 
diff --git a/src/merge/output_control.cpp b/src/merge/output_control.cpp
index 663570d42..f57fff824 100644
--- a/src/merge/output_control.cpp
+++ b/src/merge/output_control.cpp
@@ -304,7 +304,7 @@ display_progress(bool is_100percent = false) {
 
   bool display_progress  = false;
   int current_percentage = (s_display_reader->get_progress() + s_display_files_done * 100) / s_display_path_length;
-  int64_t current_time   = get_current_time_millis();
+  int64_t current_time   = mtx::sys::get_current_time_millis();
 
   if (   (-1 == s_previous_percentage)
       || ((100 == current_percentage) && (100 > s_previous_percentage))
diff --git a/src/mkvtoolnix-gui/main_window/main_window.cpp b/src/mkvtoolnix-gui/main_window/main_window.cpp
index e665cc3ef..5739d969e 100644
--- a/src/mkvtoolnix-gui/main_window/main_window.cpp
+++ b/src/mkvtoolnix-gui/main_window/main_window.cpp
@@ -246,7 +246,7 @@ MainWindow::checkForUpdates() {
 
 void
 MainWindow::silentlyCheckForUpdates() {
-  auto forceUpdateCheck = get_environment_variable("FORCE_UPDATE_CHECK") == "1";
+  auto forceUpdateCheck = mtx::sys::get_environment_variable("FORCE_UPDATE_CHECK") == "1";
 
   if (!forceUpdateCheck && !Util::Settings::get().m_checkForUpdates)
     return;
@@ -275,7 +275,7 @@ MainWindow::updateCheckFinished(UpdateCheckStatus status,
 
   auto &settings             = Util::Settings::get();
   settings.m_lastUpdateCheck = QDateTime::currentDateTime();
-  auto forceUpdateCheck      = get_environment_variable("FORCE_UPDATE_CHECK") == "1";
+  auto forceUpdateCheck      = mtx::sys::get_environment_variable("FORCE_UPDATE_CHECK") == "1";
 
   if (!forceUpdateCheck && !(release.current_version < release.latest_source))
     return;
diff --git a/src/mkvtoolnix-gui/mkvtoolnix_gui.cpp b/src/mkvtoolnix-gui/mkvtoolnix_gui.cpp
index c19539a1b..ac5fbe44c 100644
--- a/src/mkvtoolnix-gui/mkvtoolnix_gui.cpp
+++ b/src/mkvtoolnix-gui/mkvtoolnix_gui.cpp
@@ -30,7 +30,7 @@ registerMetaTypes() {
 
 static void
 showPreviewWarning(QWidget *parent) {
-  if (get_environment_variable("NO_WARNING") == "1")
+  if (mtx::sys::get_environment_variable("NO_WARNING") == "1")
     return;
 
   auto dlg = std::make_unique<PreviewWarningDialog>(parent);
diff --git a/src/mkvtoolnix-gui/util/settings.cpp b/src/mkvtoolnix-gui/util/settings.cpp
index d94a37b6a..b8202b56e 100644
--- a/src/mkvtoolnix-gui/util/settings.cpp
+++ b/src/mkvtoolnix-gui/util/settings.cpp
@@ -112,7 +112,7 @@ Settings::exeWithPath(QString const &exe) {
   if (path.is_absolute())
     return exe;
 
-  return to_qs((mtx::get_installation_path() / path).native());
+  return to_qs((mtx::sys::get_installation_path() / path).native());
 #else  // defined(SYS_WINDOWS)
   return exe;
 #endif // defined(SYS_WINDOWS)
diff --git a/src/mmg/helpers.cpp b/src/mmg/helpers.cpp
index e6f341a1b..9c1784d36 100644
--- a/src/mmg/helpers.cpp
+++ b/src/mmg/helpers.cpp
@@ -277,7 +277,7 @@ format_tooltip(const wxString &s) {
 
 wxString
 get_temp_settings_file_name() {
-  return wxU((bfs::temp_directory_path() / (boost::format("mmg-mkvmerge-options-%1%-%2%") % wxGetProcessId() % get_current_time_millis()).str()).string());
+  return wxU((bfs::temp_directory_path() / (boost::format("mmg-mkvmerge-options-%1%-%2%") % wxGetProcessId() % mtx::sys::get_current_time_millis()).str()).string());
 }
 
 wxString
diff --git a/src/mmg/jobs.cpp b/src/mmg/jobs.cpp
index 605b969b1..3c558b75a 100644
--- a/src/mmg/jobs.cpp
+++ b/src/mmg/jobs.cpp
@@ -112,11 +112,11 @@ job_run_dialog::job_run_dialog(wxWindow *,
   m_geometry_saver.set_default_size(700, 700, true).restore();
 
 #if defined(SYS_WINDOWS)
-  if (get_windows_version() >= WINDOWS_VERSION_7)
+  if (mtx::sys::get_windows_version() >= WINDOWS_VERSION_7)
     m_taskbar_progress = new taskbar_progress_c(this);
 #endif
 
-  m_start_time_total                 = get_current_time_millis();
+  m_start_time_total                 = mtx::sys::get_current_time_millis();
   m_next_remaining_time_update_total = m_start_time_total + 8000;
 
   start_next_job();
@@ -155,7 +155,7 @@ job_run_dialog::start_next_job() {
     return;
   }
 
-  m_start_time                 = get_current_time_millis();
+  m_start_time                 = mtx::sys::get_current_time_millis();
   m_next_remaining_time_update = m_start_time + 8000;
   st_remaining_time->SetLabel(Z("is being estimated"));
 
@@ -251,7 +251,7 @@ job_run_dialog::process_input() {
       else if (wx_line.Find(wxT("#GUI#end_scanning_playlists")) == 0) {
         m_scanning_playlists         = false;
 
-        m_start_time                 = get_current_time_millis();
+        m_start_time                 = mtx::sys::get_current_time_millis();
         m_next_remaining_time_update = m_start_time + 8000;
 
         if (!current_job) {
@@ -300,7 +300,7 @@ job_run_dialog::update_remaining_time() {
   if (m_scanning_playlists || !m_progress)
     return;
 
-  int64_t now = get_current_time_millis();
+  int64_t now = mtx::sys::get_current_time_millis();
 
   if ((0 != (m_progress % 100)) && (now >= m_next_remaining_time_update)) {
     int64_t total_time           = (now - m_start_time) * 100 / (m_progress % 100);
diff --git a/src/mmg/mmg.cpp b/src/mmg/mmg.cpp
index fa6e9e928..44ab68750 100644
--- a/src/mmg/mmg.cpp
+++ b/src/mmg/mmg.cpp
@@ -112,7 +112,7 @@ mmg_app::init_ui_locale() {
   m_ui_locale = locale;
 
   if (s_first_init) {
-    auto installation_path = mtx::get_installation_path();
+    auto installation_path = mtx::sys::get_installation_path();
     if (!installation_path.empty())
       wxLocale::AddCatalogLookupPathPrefix(wxU((installation_path / "locale").string()));
 
@@ -139,9 +139,9 @@ wxString
 mmg_app::get_config_file_name()
   const {
 #ifdef SYS_WINDOWS
-  return wxU((mtx::get_installation_path() / "mkvtoolnix.ini").string());
+  return wxU((mtx::sys::get_installation_path() / "mkvtoolnix.ini").string());
 #else
-  return wxU((mtx::get_application_data_folder() / "config").string());
+  return wxU((mtx::sys::get_application_data_folder() / "config").string());
 #endif
 }
 
@@ -149,9 +149,9 @@ wxString
 mmg_app::get_jobs_folder()
   const {
 #if defined(SYS_WINDOWS)
-  return m_is_installed ? wxU(mtx::get_application_data_folder().string()) : wxU((mtx::get_installation_path() / "jobs").string());
+  return m_is_installed ? wxU(mtx::sys::get_application_data_folder().string()) : wxU((mtx::sys::get_installation_path() / "jobs").string());
 #else
-  return wxU((mtx::get_application_data_folder() / "jobs").string());
+  return wxU((mtx::sys::get_application_data_folder() / "jobs").string());
 #endif
 }
 
diff --git a/src/mmg/mmg_dialog.cpp b/src/mmg/mmg_dialog.cpp
index 43757b5bc..c6d4c643b 100644
--- a/src/mmg/mmg_dialog.cpp
+++ b/src/mmg/mmg_dialog.cpp
@@ -665,7 +665,7 @@ mmg_dialog::display_help(int id) {
     wxDirDialog dlg(this, Z("Choose the location of the mkvmerge GUI help files"));
     std::vector<wxString> potential_help_paths;
 
-    wxString installation_path = wxU(mtx::get_installation_path().string());
+    wxString installation_path = wxU(mtx::sys::get_installation_path().string());
     if (!installation_path.IsEmpty())
       potential_help_paths.push_back(installation_path + wxT("/doc"));
 
diff --git a/src/mmg/mmg_options.cpp b/src/mmg/mmg_options.cpp
index 75642b1f0..61bae4d12 100644
--- a/src/mmg/mmg_options.cpp
+++ b/src/mmg/mmg_options.cpp
@@ -81,7 +81,7 @@ mmg_options_t::mkvmerge_exe() {
     exe = bfs::path{};
 
   if (exe.empty()) {
-    exe = mtx::get_installation_path();
+    exe = mtx::sys::get_installation_path();
     if (!exe.empty() && bfs::exists(exe) && bfs::exists(exe / exe_with_ext))
       exe = exe / exe_with_ext;
     else
@@ -91,7 +91,7 @@ mmg_options_t::mkvmerge_exe() {
   if (exe.empty())
     exe = exe_with_ext;
 
-  wxLogMessage(wxT("mkvmerge_exe %s installation_path %s\n"), wxU(exe.string()).c_str(), wxU(mtx::get_installation_path().string()).c_str());
+  wxLogMessage(wxT("mkvmerge_exe %s installation_path %s\n"), wxU(exe.string()).c_str(), wxU(mtx::sys::get_installation_path().string()).c_str());
 
   return wxU(exe.string());
 }
diff --git a/src/mmg/mux_dialog.cpp b/src/mmg/mux_dialog.cpp
index c2a41e6cc..dda691054 100644
--- a/src/mmg/mux_dialog.cpp
+++ b/src/mmg/mux_dialog.cpp
@@ -123,7 +123,7 @@ mux_dialog::run() {
   }
 
 #if defined(SYS_WINDOWS)
-  if (get_windows_version() >= WINDOWS_VERSION_7) {
+  if (mtx::sys::get_windows_version() >= WINDOWS_VERSION_7) {
     m_taskbar_progress = new taskbar_progress_c(mdlg);
     m_taskbar_progress->set_state(TBPF_NORMAL);
     m_taskbar_progress->set_value(0, 100);
@@ -132,7 +132,7 @@ mux_dialog::run() {
 
   update_label(Z("Muxing in progress."));
 
-  m_start_time                 = get_current_time_millis();
+  m_start_time                 = mtx::sys::get_current_time_millis();
   m_next_remaining_time_update = m_start_time + 8000;
 
   m_process                    = new mux_process{this};
@@ -187,7 +187,7 @@ mux_dialog::update_remaining_time() {
   if (m_scanning_playlists)
     return;
 
-  int64_t now = get_current_time_millis();
+  int64_t now = mtx::sys::get_current_time_millis();
 
   if ((0 == m_progress) || (now < m_next_remaining_time_update))
     return;
@@ -289,7 +289,7 @@ mux_dialog::on_output_available(wxCommandEvent &evt) {
   else if (line.Find(wxT("#GUI#end_scanning_playlists")) == 0) {
     m_scanning_playlists         = false;
 
-    m_start_time                 = get_current_time_millis();
+    m_start_time                 = mtx::sys::get_current_time_millis();
     m_next_remaining_time_update = m_start_time + 8000;
 
   } else if (line.Find(Z("Progress")) == 0) {
diff --git a/src/mmg/tabs/scan_directory_thread.cpp b/src/mmg/tabs/scan_directory_thread.cpp
index 43ad2a3fe..5fb4d3656 100644
--- a/src/mmg/tabs/scan_directory_thread.cpp
+++ b/src/mmg/tabs/scan_directory_thread.cpp
@@ -89,7 +89,7 @@ scan_directory_thread_c::identify_file(wxString const &file_name)
 
   // log_it(boost::format("command: %1%\n") % to_utf8(command));
 
-  int result = mtx::system(to_utf8(command));
+  int result = mtx::sys::system(to_utf8(command));
 
   try {
     mm_text_io_c in{new mm_file_io_c{to_utf8(opt_file_name + wxT("-out")), MODE_READ}};
diff --git a/src/mmg/tabs/scanning_for_playlists_dlg.cpp b/src/mmg/tabs/scanning_for_playlists_dlg.cpp
index 35c7811b0..c05710a1f 100644
--- a/src/mmg/tabs/scanning_for_playlists_dlg.cpp
+++ b/src/mmg/tabs/scanning_for_playlists_dlg.cpp
@@ -45,7 +45,7 @@ scanning_for_playlists_dlg::scanning_for_playlists_dlg(wxWindow *parent,
 	m_b_abort               = new wxButton(    this, wxID_CANCEL, Z("&Abort"));
 
 #if defined(SYS_WINDOWS)
-  if (get_windows_version() >= WINDOWS_VERSION_7) {
+  if (mtx::sys::get_windows_version() >= WINDOWS_VERSION_7) {
     m_taskbar_progress = new taskbar_progress_c(mdlg);
     m_taskbar_progress->set_state(TBPF_NORMAL);
     m_taskbar_progress->set_value(0, other_file_names.size());
@@ -91,7 +91,7 @@ scanning_for_playlists_dlg::~scanning_for_playlists_dlg()
 
 int
 scanning_for_playlists_dlg::scan() {
-  m_start_time                 = get_current_time_millis();
+  m_start_time                 = mtx::sys::get_current_time_millis();
   m_next_remaining_time_update = m_start_time + 8000;
 
   m_scanner->Create();
@@ -129,7 +129,7 @@ void
 scanning_for_playlists_dlg::on_progress_changed(wxCommandEvent &evt) {
   update_gauge(evt.GetInt());
 
-  uint64_t now = get_current_time_millis();
+  uint64_t now = mtx::sys::get_current_time_millis();
 
   if ((0 == m_progress) || (now < m_next_remaining_time_update))
     return;