1 files changed, 18 insertions, 0 deletions
diff --git a/taglib/mp4/mp4file.cpp b/taglib/mp4/mp4file.cpp
index 3733fb40..5ad8396d 100644
--- a/taglib/mp4/mp4file.cpp
+++ b/taglib/mp4/mp4file.cpp
@@ -26,6 +26,8 @@
 #include <tdebug.h>
 #include <tstring.h>
 #include <tpropertymap.h>
+#include <tagutils.h>
+
 #include "mp4atom.h"
 #include "mp4tag.h"
 #include "mp4file.h"
@@ -69,6 +71,22 @@ public:
   MP4::Properties *properties;
 };
 
+////////////////////////////////////////////////////////////////////////////////
+// static members
+////////////////////////////////////////////////////////////////////////////////
+
+bool MP4::File::isSupported(IOStream *stream)
+{
+  // An MP4 file has to have an "ftyp" box first.
+
+  const ByteVector id = Utils::readHeader(stream, 8, false);
+  return id.containsAt("ftyp", 4);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// public members
+////////////////////////////////////////////////////////////////////////////////
+
 MP4::File::File(FileName file, bool readProperties, AudioProperties::ReadStyle) :
   TagLib::File(file),
   d(new FilePrivate())