[FragmentedSampleReader] Create senc when saio/saiz/senc are missing

src/samplereader/FragmentedSampleReader.cpp

@@ -22,6 +22,8 @@
 #include "utils/Utils.h"
 #include "utils/log.h"
 
+#include <bento4/Ap4SencAtom.h>
+
 using namespace UTILS;
 
 namespace
@@ -386,6 +388,14 @@ AP4_Result CFragmentedSampleReader::ProcessMoof(AP4_ContainerAtom* moof,
       if (!m_protectedDesc || !traf)
         return AP4_ERROR_INVALID_FORMAT;
 
+      // If the boxes saiz, saio, senc are missing, the stream does not conform to the specs and
+      // may not be decrypted, so try create an empty senc where all samples will use the same default IV
+      if (!traf->GetChild(AP4_ATOM_TYPE_SAIO) && !traf->GetChild(AP4_ATOM_TYPE_SAIZ) &&
+          !traf->GetChild(AP4_ATOM_TYPE_SENC))
+      {
+        traf->AddChild(new AP4_SencAtom());
+      }
+
       bool reset_iv(false);
       if (AP4_FAILED(result = AP4_CencSampleInfoTable::Create(m_protectedDesc, traf, algorithm_id,
                                                               reset_iv, *m_FragmentStream,