From a6aefce178e577373c527c1966209428b762d4a8 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Tue, 7 Dec 2021 21:24:27 +0100
Subject: [PATCH] WIP: Read display unit

---
 matroska/matroskatrack.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/matroska/matroskatrack.cpp b/matroska/matroskatrack.cpp
index 9e4c28d..56b56ff 100644
--- a/matroska/matroskatrack.cpp
+++ b/matroska/matroskatrack.cpp
@@ -296,6 +296,7 @@ void MatroskaTrack::internalParseHeader(Diagnostics &diag, AbortableProgressFeed
     }
     // read information about the track from the children of the track entry element
     auto hasIsoLanguage = false;
+    auto displayUnit = std::uint64_t(0);
     for (EbmlElement *trackInfoElement = m_trackElement->firstChild(), *subElement = nullptr; trackInfoElement;
          trackInfoElement = trackInfoElement->nextSibling()) {
         try {
@@ -342,6 +343,9 @@ void MatroskaTrack::internalParseHeader(Diagnostics &diag, AbortableProgressFeed
                 case MatroskaIds::DisplayHeight:
                     m_displaySize.setHeight(static_cast<std::uint32_t>(subElement->readUInteger()));
                     break;
+                case MatroskaIds::DisplayUnit:
+                    displayUnit = subElement->readUInteger();
+                    break;
                 case MatroskaIds::PixelWidth:
                     m_pixelSize.setWidth(static_cast<std::uint32_t>(subElement->readUInteger()));
                     break;
@@ -533,6 +537,16 @@ void MatroskaTrack::internalParseHeader(Diagnostics &diag, AbortableProgressFeed
         m_formatName.append(" (unknown)");
     }
 
+    // assign display unit
+    switch (displayUnit) {
+    case 0: // pixels
+    case 1: // centimeters
+    case 2: // inches
+    case 3: // display aspect ratio
+    default: // unknown
+        ;
+    }
+
     // use pixel size as display size if display size not specified
     if (!m_displaySize.width()) {
         m_displaySize.setWidth(m_pixelSize.width());