Remove void elements from masters recursively when overwriting elements

src/common/ebml.cpp

@@ -27,6 +27,7 @@
 #include <ebml/EbmlString.h>
 #include <ebml/EbmlUInteger.h>
 #include <ebml/EbmlUnicodeString.h>
+#include <ebml/EbmlVoid.h>
 
 #include <matroska/KaxChapters.h>
 #include <matroska/KaxTags.h>
@@ -593,3 +594,22 @@ fix_mandatory_elements(EbmlElement *master) {
   else if (NULL != dynamic_cast<KaxChapters *>(master))
     fix_mandatory_chapter_elements(master);
 }
+
+void
+remove_voids_from_master(EbmlElement *element) {
+  EbmlMaster *master = dynamic_cast<EbmlMaster *>(element);
+  if (NULL == master)
+    return;
+
+  size_t idx = 0;
+  while (master->ListSize() > idx) {
+    element = (*master)[idx];
+    if (NULL != dynamic_cast<EbmlVoid *>(element))
+      master->Remove(idx);
+
+    else {
+      remove_voids_from_master(element);
+      ++idx;
+    }
+  }
+}

src/common/ebml.h

@@ -183,6 +183,7 @@ GetFirstOrNextChild(EbmlMaster *master,
 EbmlElement *MTX_DLL_API empty_ebml_master(EbmlElement *e);
 EbmlElement *MTX_DLL_API create_ebml_element(const EbmlCallbacks &callbacks, const EbmlId &id);
 EbmlMaster *MTX_DLL_API sort_ebml_master(EbmlMaster *e);
+void MTX_DLL_API remove_voids_from_master(EbmlElement *element);
 
 const EbmlCallbacks *MTX_DLL_API find_ebml_callbacks(const EbmlCallbacks &base, const EbmlId &id);
 const EbmlCallbacks *MTX_DLL_API find_ebml_callbacks(const EbmlCallbacks &base, const char *debug_name);

src/common/kax_analyzer.cpp

@@ -326,6 +326,7 @@ kax_analyzer_c::update_element(EbmlElement *e,
   reopen_file();
 
   fix_mandatory_elements(e);
+  remove_voids_from_master(e);
 
   placement_strategy_e strategy = get_placement_strategy_for(e);