diff --git a/Source/C++/Codecs/Ap4Ac4Parser.cpp b/Source/C++/Codecs/Ap4Ac4Parser.cpp
index 7d0386dc..7fc7f835 100644
--- a/Source/C++/Codecs/Ap4Ac4Parser.cpp
+++ b/Source/C++/Codecs/Ap4Ac4Parser.cpp
@@ -503,7 +503,35 @@ AP4_Ac4Parser::FindFrame(AP4_Ac4Frame& frame)
     frame.m_Info.m_Ac4Dsi.d.v1.ac4_bitrate_dsi.bit_rate = 0;                    // unknown, fixed value now
     frame.m_Info.m_Ac4Dsi.d.v1.ac4_bitrate_dsi.bit_rate_precision = 0xffffffff; // unknown, fixed value now
     frame.m_Info.m_Ac4Dsi.d.v1.n_presentations = ac4_header.m_NPresentations;
-    frame.m_Info.m_Ac4Dsi.d.v1.presentations   = ac4_header.m_PresentationV1;
+
+    if (ac4_header.m_PresentationV1) {
+        assert(ac4_header.m_PresentationV1 != NULL);
+        frame.m_Info.m_Ac4Dsi.d.v1.presentations = new AP4_Dac4Atom::Ac4Dsi::PresentationV1[ac4_header.m_NPresentations];
+        AP4_CopyMemory(frame.m_Info.m_Ac4Dsi.d.v1.presentations,
+                       ac4_header.m_PresentationV1,
+                       sizeof(AP4_Dac4Atom::Ac4Dsi::PresentationV1) * ac4_header.m_NPresentations);
+        for (unsigned int pres_idx = 0; pres_idx < ac4_header.m_NPresentations; pres_idx++) {
+            assert(ac4_header.m_PresentationV1[pres_idx].d.v1.substream_groups != NULL);
+            int n_substream_group = ac4_header.m_PresentationV1[pres_idx].d.v1.n_substream_groups;
+            frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_groups = new AP4_Dac4Atom::Ac4Dsi::SubStreamGroupV1[n_substream_group];
+            frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_group_indexs = new AP4_UI32[n_substream_group];
+            AP4_CopyMemory(frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_group_indexs,
+                           ac4_header.m_PresentationV1[pres_idx].d.v1.substream_group_indexs,
+                           sizeof(AP4_UI32)*n_substream_group);
+            AP4_CopyMemory(frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_groups,
+                           ac4_header.m_PresentationV1[pres_idx].d.v1.substream_groups,
+                           sizeof(AP4_Dac4Atom::Ac4Dsi::SubStreamGroupV1)*n_substream_group);
+            for (unsigned int sg_idx = 0; sg_idx < n_substream_group; sg_idx++) {
+                assert(ac4_header.m_PresentationV1[pres_idx].d.v1.substream_groups[sg_idx].d.v1.substreams != NULL);
+                int n_substreams = ac4_header.m_PresentationV1[pres_idx].d.v1.substream_groups[sg_idx].d.v1.n_substreams;
+                frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_groups[sg_idx].d.v1.substreams
+                    = new AP4_Dac4Atom::Ac4Dsi::SubStream[n_substreams];
+                AP4_CopyMemory(frame.m_Info.m_Ac4Dsi.d.v1.presentations[pres_idx].d.v1.substream_groups[sg_idx].d.v1.substreams,
+                               ac4_header.m_PresentationV1[pres_idx].d.v1.substream_groups[sg_idx].d.v1.substreams,
+                               sizeof(AP4_Dac4Atom::Ac4Dsi::SubStream) * n_substreams);
+            }
+        }
+    }
 
     /* set the frame source */
     frame.m_Source = &m_Bits;
diff --git a/Source/C++/Core/Ap4Dac4Atom.cpp b/Source/C++/Core/Ap4Dac4Atom.cpp
index 942f753b..07315f79 100644
--- a/Source/C++/Core/Ap4Dac4Atom.cpp
+++ b/Source/C++/Core/Ap4Dac4Atom.cpp
@@ -967,7 +967,7 @@ AP4_Dac4Atom::Ac4Dsi::SubStream::ParseSubstreamIdxInfo(AP4_BitReader &bits, unsi
 {
     if (b_substreams_present == 1) {
         if (bits.ReadBits(2) == 3) {    // substream_index
-            AP4_Ac4VariableBits(bits, 2);
+            ss_idx = AP4_Ac4VariableBits(bits, 2);
         }
     }
     return AP4_SUCCESS;
diff --git a/Source/C++/Core/Ap4Dac4Atom.h b/Source/C++/Core/Ap4Dac4Atom.h
index 227c50a8..f39f6446 100644
--- a/Source/C++/Core/Ap4Dac4Atom.h
+++ b/Source/C++/Core/Ap4Dac4Atom.h
@@ -81,6 +81,7 @@ class AP4_Dac4Atom : public AP4_Atom
             AP4_UI08 b_substream_contains_bed_objects;
             AP4_UI08 b_substream_contains_dynamic_objects;
             AP4_UI08 b_substream_contains_ISF_objects;
+            AP4_UI08 ss_idx;
 
             // methods
             AP4_Result ParseSubstreamInfoChan(AP4_BitReader &bits,