diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7f7918d9..9e453306 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -52,6 +52,6 @@ jobs:
       # Upload the SDK
       - name: Upload SDK
         if: github.event_name == 'push'
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           path: SDK/*.zip
diff --git a/Source/C++/Core/Ap4Dac4Atom.cpp b/Source/C++/Core/Ap4Dac4Atom.cpp
index b9ed4060..942f753b 100644
--- a/Source/C++/Core/Ap4Dac4Atom.cpp
+++ b/Source/C++/Core/Ap4Dac4Atom.cpp
@@ -664,11 +664,12 @@ AP4_Dac4Atom::Ac4Dsi::SubStream::ParseSubStreamInfoAjoc(AP4_BitReader &bits,
         // oamd_common_data()
         ParseOamdCommonData(bits);
     }
-    n_umx_objects_minus1 = bits.ReadBits(4);
-    int nFullbandUpmixSignals = n_umx_objects_minus1 + 1;
+    int nFullbandUpmixSignalsMinus = bits.ReadBits(4);
+    int nFullbandUpmixSignals = nFullbandUpmixSignalsMinus + 1;
     if (nFullbandUpmixSignals == 16) {
         nFullbandUpmixSignals += AP4_Ac4VariableBits(bits, 3);
     }
+    n_umx_objects_minus1 = nFullbandUpmixSignals - 1;
 
     BedDynObjAssignment(bits, nFullbandUpmixSignals, true);
     ParseDsiSfMutiplier(bits, fs_idx);