qtdemux: Add 'aavd' and related fourcc codes for AAX encrypted audio

The 'aavd' box is contained in the 'stsd' sample description. The 'aavd'
box follows the layout of an 'mp4a' entry, i.e. it contains a single
standard 'esds' extension box, and the two proprietary 'adrm' and 'aabd'
extension boxes.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/577>

gst/isomp4/fourcc.h

@@ -403,6 +403,10 @@ G_BEGIN_DECLS
 #define FOURCC_tenc     GST_MAKE_FOURCC('t','e','n','c')
 #define FOURCC_cenc     GST_MAKE_FOURCC('c','e','n','c')
 
+/* Audible AAX encrypted audio */
+#define FOURCC_aavd     GST_MAKE_FOURCC('a','a','v','d')
+#define FOURCC_adrm     GST_MAKE_FOURCC('a','d','r','m')
+
 G_END_DECLS
 
 #endif /* __FOURCC_H__ */

gst/isomp4/qtdemux.c

@@ -7856,6 +7856,7 @@ qtdemux_parse_node (GstQTDemux * qtdemux, GNode * node, const guint8 * buffer,
       case FOURCC_mp4a:
       case FOURCC_alac:
       case FOURCC_fLaC:
+      case FOURCC_aavd:
       {
         guint32 version;
         guint32 offset;

gst/isomp4/qtdemux_types.c

@@ -225,6 +225,8 @@ static const QtNodeType qt_node_types[] = {
   {FOURCC_av1m, "AV1 Multi-Frame sample group entry", 0},
   {FOURCC_av1s, "AV1 S-Frame sample group entry", 0},
   {FOURCC_av1M, "AV1 Metadata sample group entry", 0},
+  {FOURCC_aavd, "AAX encrypted audio", 0},
+  {FOURCC_adrm, "AAX DRM key data", 0},
   {0, "unknown", 0,},
 };