diff --git a/mp4/mp4container.cpp b/mp4/mp4container.cpp
index 4511fbd..2e80913 100644
--- a/mp4/mp4container.cpp
+++ b/mp4/mp4container.cpp
@@ -28,6 +28,11 @@ namespace TagParser {
  * \brief Implementation of GenericContainer<MediaFileInfo, Mp4Tag, Mp4Track, Mp4Atom>.
  */
 
+/*!
+ * \brief Dates within MP4 tracks are expressed as the number of seconds since this date.
+ */
+const CppUtilities::DateTime Mp4Container::epoch = DateTime::fromDate(1904, 1, 1);
+
 /*!
  * \brief Constructs a new container for the specified \a fileInfo at the specified \a startOffset.
  */
@@ -132,19 +137,15 @@ void Mp4Container::internalParseTracks(Diagnostics &diag, AbortableProgressFeedb
                         stream().seekg(3, ios_base::cur); // skip flags
                         switch (version) {
                         case 0:
-                            m_creationTime
-                                = DateTime::fromDate(1904, 1, 1) + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt32BE()));
-                            m_modificationTime
-                                = DateTime::fromDate(1904, 1, 1) + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt32BE()));
+                            m_creationTime = epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt32BE()));
+                            m_modificationTime = epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt32BE()));
                             m_timeScale = reader().readUInt32BE();
                             m_duration = TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt32BE()))
                                 / static_cast<TimeSpan::TickType>(m_timeScale);
                             break;
                         case 1:
-                            m_creationTime
-                                = DateTime::fromDate(1904, 1, 1) + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt64BE()));
-                            m_modificationTime
-                                = DateTime::fromDate(1904, 1, 1) + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt64BE()));
+                            m_creationTime = epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt64BE()));
+                            m_modificationTime = epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt64BE()));
                             m_timeScale = reader().readUInt32BE();
                             m_duration = TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(reader().readUInt64BE()))
                                 / static_cast<TimeSpan::TickType>(m_timeScale);
diff --git a/mp4/mp4container.h b/mp4/mp4container.h
index e26f931..c636947 100644
--- a/mp4/mp4container.h
+++ b/mp4/mp4container.h
@@ -26,6 +26,8 @@ public:
     ElementPosition determineTagPosition(Diagnostics &diag) const override;
     ElementPosition determineIndexPosition(Diagnostics &diag) const override;
 
+    static const CppUtilities::DateTime epoch;
+
 protected:
     void internalParseHeader(Diagnostics &diag, AbortableProgressFeedback &progress) override;
     void internalParseTags(Diagnostics &diag, AbortableProgressFeedback &progress) override;
diff --git a/mp4/mp4track.cpp b/mp4/mp4track.cpp
index 947197c..01372e9 100644
--- a/mp4/mp4track.cpp
+++ b/mp4/mp4track.cpp
@@ -89,9 +89,6 @@ constexpr std::uint8_t Mp4Timings::requiredMdhdVersion() const
         : 0;
 }
 
-/// \brief Dates within MP4 tracks are expressed as the number of seconds since this date.
-static const auto startDate = DateTime::fromDate(1904, 1, 1);
-
 /*!
  * \class Mpeg4AudioSpecificConfig
  * \brief The Mpeg4AudioSpecificConfig class holds MPEG-4 audio specific config parsed using Mp4Track::parseAudioSpecificConfig().
@@ -499,8 +496,9 @@ Mp4Timings Mp4Track::computeTimings() const
         timings.mdhdModificationTime = m_rawMdhdModificationTime;
         timings.mdhdDuration = m_rawMdhdDuration;
     } else {
-        timings.tkhdCreationTime = timings.mdhdCreationTime = static_cast<std::uint64_t>((m_creationTime - startDate).totalSeconds());
-        timings.tkhdModificationTime = timings.mdhdModificationTime = static_cast<std::uint64_t>((m_modificationTime - startDate).totalSeconds());
+        timings.tkhdCreationTime = timings.mdhdCreationTime = static_cast<std::uint64_t>((m_creationTime - Mp4Container::epoch).totalSeconds());
+        timings.tkhdModificationTime = timings.mdhdModificationTime
+            = static_cast<std::uint64_t>((m_modificationTime - Mp4Container::epoch).totalSeconds());
         timings.tkhdDuration = timings.mdhdDuration = static_cast<std::uint64_t>(m_duration.totalTicks() * m_timeScale / TimeSpan::ticksPerSecond);
     }
     return timings;
@@ -1634,8 +1632,8 @@ void Mp4Track::internalParseHeader(Diagnostics &diag, AbortableProgressFeedback
         m_timeScale = 0;
         m_duration = TimeSpan();
     }
-    m_creationTime = startDate + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(m_rawMdhdCreationTime));
-    m_modificationTime = startDate + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(m_rawMdhdModificationTime));
+    m_creationTime = Mp4Container::epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(m_rawMdhdCreationTime));
+    m_modificationTime = Mp4Container::epoch + TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(m_rawMdhdModificationTime));
     m_duration = TimeSpan::fromSeconds(static_cast<TimeSpan::TickType>(m_rawMdhdDuration)) / static_cast<TimeSpan::TickType>(m_timeScale);
 
     std::uint16_t tmp = reader.readUInt16BE();