KaxSemantic.cpp: make KaxVideoAlphaMode mandatory

See https://github.com/ietf-wg-cellar/matroska-specification/commit/5aa6c928caac5300b0ab1a65522e9be31710b2b0

diff --git a/src/KaxSemantic.cpp b/src/KaxSemantic.cpp
index e7c6c4ee1fa08edda043f6c0d2a23e9bc737a7c8..c28438fc5f2e2299b6da200d0f6950ebc5a15a39 100644 (file)
--- a/src/KaxSemantic.cpp
+++ b/src/KaxSemantic.cpp
@@ -322,7 +322,7 @@ DEFINE_START_SEMANTIC(KaxTrackVideo)
 DEFINE_SEMANTIC_ITEM(true, true, KaxVideoFlagInterlaced)
 DEFINE_SEMANTIC_ITEM(true, true, KaxVideoFieldOrder)
 DEFINE_SEMANTIC_ITEM(true, true, KaxVideoStereoMode)
-DEFINE_SEMANTIC_ITEM(false, true, KaxVideoAlphaMode)
+DEFINE_SEMANTIC_ITEM(true, true, KaxVideoAlphaMode)
 DEFINE_SEMANTIC_ITEM(false, true, KaxOldStereoMode) // not supported
 DEFINE_SEMANTIC_ITEM(true, true, KaxVideoPixelWidth)
 DEFINE_SEMANTIC_ITEM(true, true, KaxVideoPixelHeight)