diff --git a/src/common/compression.cpp b/src/common/compression.cpp
index 38fe2867a..299b4d443 100644
--- a/src/common/compression.cpp
+++ b/src/common/compression.cpp
@@ -20,6 +20,7 @@
 
 #include "commonebml.h"
 #include "compression.h"
+#include "hacks.h"
 
 using namespace libmatroska;
 
@@ -314,6 +315,17 @@ header_removal_compressor_c::set_track_headers(KaxContentEncoding
     SetBuffer(m_bytes->get(), m_bytes->get_size());
 }
 
+mpeg4_p2_compressor_c::mpeg4_p2_compressor_c() {
+  if (!hack_engaged(ENGAGE_NATIVE_MPEG4))
+    mxerror("The MPEG-4 part 2 compression only works with native MPEG-4. "
+            "However, native MPEG-4 mode has not been selected with "
+            "'--engage native_mpeg4'.\n");
+
+  memory_cptr bytes(new memory_c((unsigned char *)safemalloc(4), 4, true));
+  put_uint32_be(bytes->get(), 0x000001b6);
+  set_bytes(bytes);
+}
+
 // ---------------------------------------------------------------------
 
 compressor_c::~compressor_c() {
diff --git a/src/common/compression.h b/src/common/compression.h
index 35cc5f092..4fd4ace61 100644
--- a/src/common/compression.h
+++ b/src/common/compression.h
@@ -142,11 +142,7 @@ public:
 
 class MTX_DLL_API mpeg4_p2_compressor_c: public header_removal_compressor_c {
 public:
-  mpeg4_p2_compressor_c() {
-    memory_cptr bytes(new memory_c((unsigned char *)safemalloc(4), 4, true));
-    put_uint32_be(bytes->get(), 0x000001b6);
-    set_bytes(bytes);
-  }
+  mpeg4_p2_compressor_c();
 };
 
 // ------------------------------------------------------------------